In this guide, I’ll walk you through everything you need to know about the best dynamo lights. We’ll start with the technical basics – lumens, lux, and beam shapes. Then I’ll cover features like adjustable beam modes, USB charging, and how to choose the right light for your bike.

Once you have a solid understanding of how they work, I’ll share my top picks for the best dynamo lights currently available, both for on-road and off-road riding. We’ll compare them side by side, focusing on their beam shapes to highlight how each performs in real-world conditions.

Keep in mind: there’s no one-size-fits-all solution. The ideal light for you will depend on your riding conditions, the beam shape you prefer, how much brightness you need, and whether USB charging is a priority.

This article was originally published in April 2017 but has been updated in May 2025.

Lumens and Lux

The light output at the source is measured in lumens (lm), which is a helpful unit for comparing the raw output of different LED bulbs.

Lux measures the brightness at a specific distance – that is, the amount of light falling on a surface. In Germany, regulations define lux by measuring the illumination cast on a white wall from 10 metres away.

For most everyday, non-technical riding, a light rated at 80 lux or roughly 200 lm is more than sufficient. But if you’re tackling more demanding terrain, look for lights with at least 100 lux or 300 lm for improved visibility and safety.

Keep in mind that lumens and lux reflect different aspects of performance. Two lights with the same lumen rating can deliver dramatically different results depending on how their beams are shaped. For instance, a wide-beam, high-lumen light may result in low lux, while a low-lumen light with a tightly focused beam can achieve a much higher lux value (as illustrated in the diagram above).

That’s why evaluating beam shape is crucial when choosing a dynamo light.

Beam Shape

The beam shape is arguably the most important aspect of a dynamo light.

A light might boast a high lumen output, but if it doesn’t project light where you actually need it, it’s not much use. By combining a well-designed reflector with a moderately bright LED, you can achieve highly effective illumination using a fraction of the lumens.

The most reliable way to compare beam shapes on different dynamo lights is by using a camera setup and a test rig. Don’t worry, you’ll be able to compare photos of all the different dynamo light beam shapes at the end of this article.

Here are some websites that compare dynamo light beam shapes:
Fahrrad Zukunft
Fahrrad Beleuchtung
PeterWhiteCycles
Busch & Muller

Off-Road and On-Road Lights

Dynamo lights are generally categorised as off-road or on-road, based on how they distribute light. However, many modern cut-off beam models now offer high beam modes that make them powerful enough for off-road riding as well.

Off-road lights usually feature a round beam, much like a handheld flashlight. This design is ideal for lighting objects above your line of sight, such as low-hanging branches or trail markers. Because the beam is round, these lights can also be mounted upside down without altering the beam shape.

On-road lights feature a cut-off beam designed to light up the road efficiently and safely. The beam usually begins about 50 cm in front of the front wheel and expands in both width and distance the farther it projects.

Much like a car headlight, a reflector inside the light is engineered to limit glare at eye level, reducing the risk of blinding oncoming traffic or pedestrians. High-end reflectors can also layer the light, dimming the area closest to the rider and intensifying the brightness further out where it’s most needed.

Lights with cut-off beam shapes are often labelled as StVZO-compliant, referring to Germany’s road safety regulations. These are widely regarded as the international standard for road-legal dynamo lights and hubs.

Adjustable Beam Modes

Some dynamo lights come with adjustable beam modes, allowing you to switch between brightness levels to suit different environments. A high, long-range beam is ideal for dark rural roads, while a lower, cut-off beam works better in well-lit urban areas.

This flexibility allows you to optimise visibility for changing conditions, with high-beam modes also improving illumination while cornering. Switching between modes is typically done via a handlebar-mounted control.

Light Sensors

Some lights come with integrated light sensors that automatically switch between day and night modes. These sensors typically include a slight delay to avoid reacting to temporary changes, like oncoming car headlights, ensuring smooth transitions without unnecessary flickering.

Dynamo Lights With USB Charging

Some dynamo lights include a built-in switch that diverts power from the light to a USB charging port, providing a neat and cost-effective way to charge your devices with fewer cables.

Typically, hub dynamo USB chargers perform best when the light is off, but many newer models now allow you to charge your devices and keep your lights on simultaneously. When paired with a powerful hub like the Shimano DH-UR700 or SON 29 S (which deliver up to 50% more power than standard hubs), you’ll have more than enough power for all your needs.

For a detailed overview of the best hub dynamo USB chargers, check out my resource HERE.

What Speeds Are Required For Dynamo Lights?

Most dynamo lights begin producing usable light at speeds around 8 to 10 km/h (5–6 mph) and reach full brightness between 15 and 30 km/h (9–13 mph). Below 5 km/h, illumination drops off significantly – unless you’re using a high-output hub like the Shimano DH-UR700 or SON 29 S.

At very low speeds, many lights still provide some illumination thanks to built-in standlights. These are typically powered by small capacitors that charge during your ride.

Top-tier dynamo lights often include a small internal battery or supercapacitor. These storage cells help maintain consistent brightness and reduce flicker at lower speeds, making them ideal for slow climbs or technical terrain. They also keep the light shining brightly for a short time after you stop.

I’ve listed all the best dynamo lights with built-in batteries or supercapacitors at the end of this article.

Mounting Your Dynamo Lights

Dynamo light beam patterns are generally designed for mounting at fork crown height, just above the front wheel. However, this isn’t always feasible. Alternative mounting options include placing the light higher on the handlebars, on aero bars, or atop a front rack with a tray.

Lower mounting positions, like on a rack deck or fork blade, tend to emphasise the foreground, which can lead to shadows from obstacles such as rocks or leaves. This setup may also limit your long-range vision, as the bright foreground causes your pupils to constrict, making it harder to see further ahead.

My Full Dynamo Setup Series

If you want to learn it all, it could be worth digging into my full series on dynamo setups:

Dynamo Hubs
Dynamo USB Chargers
Dynamo Wiring
Buffer Batteries
Rim Dynamos

Best Dynamo Lights: Cut-Off Beam

SON Ladelux (800+ Lm)

The SON Ladelux is one of the most impressive dynamo lights I’ve come across. It features a powerful 150-lux low beam and an even brighter 200-lux high beam, delivering excellent visibility in all riding conditions.

A built-in 1200 mAh buffer battery ensures that the high beam remains available regardless of your speed, and also keeps your USB-powered devices charged when you’re stationary.

The beam shape is notably wide and square, with consistent brightness across the entire spread. There’s a concentrated patch of illumination near the top centre, ideally positioned to reach the farthest point on the road.

One potential downside is the stark contrast between the brightly lit area and the dark periphery. With little transition at the beam edges, the intense light could make the surrounding darkness feel even darker, creating a tunnel-like effect while riding.

A standout feature is the magnetic USB connector, located on the handlebar, along with the high and low beam switch. This clever design helps prevent water ingress and makes it easy to keep your phone or bike computer topped up during long rides.

SON Ladelux

Lumens at 20kph: 762 (high beam)
Maximum Illuminance: 200 lux
Battery For Low Speed: 1200 mAh
USB Charging: Yes
Price: €479

B&M IQ-XL (600+ Lm)

The B&M IQ-XL is one of the brightest dynamo lights available, delivering the highest lux rating of any light between 25 and 30 km/h (around 260 lux) and peaking at 300 lux.

Its beam shape is impressively wide, extending several metres beyond the reach of the Ladelux on either side. Like the Ladelux, it features a focused patch of light near the top centre of the beam, aimed to illuminate the farthest point on the road, while also offering slightly more low-level illumination around the main beam.

A handlebar-mounted button allows you to activate high beam mode. At 250 lux, the high beam projects even farther and is available from speeds as low as 10 km/h, reaching full brightness just under 50 km/h.

However, the IQ-XL lacks an internal battery, so brightness does drop at lower speeds. Still, it manages to produce around 40 lux at just 8 km/h (more than virtually all dynamo lights), so you’ll have plenty of illumination even when climbing hills.

B&M IQ-XL

Lumens at 20kph: 481 (high beam)
Maximum Illuminance: 300 lux
Battery For Low Speed: No
USB Charging: No
Price: €299

Supernova M99 DY PRO (600+ Lm)

The Supernova M99 DY PRO is a high-powered dynamo light known for its exceptionally wide beam shape. Compared to models like the Ladelux and IQ-XL, the M99 offers much more low-level illumination directly in front of the wheel and to the sides, enhancing peripheral visibility and making it easier to read the terrain around you.

With 11 LEDs and advanced control electronics, the M99 DY PRO delivers up to 1,000 lumens and 200 lux. However, the light takes some time to reach its full potential – you’ll need to be riding above 20 km/h to notice a clear advantage over most 200-lumen lights, and it only reaches peak brightness at speeds over 30 km/h.

The M99 DY Pro includes both high and low beam modes, making it versatile for city commuting and off-road use. However, it lacks a battery assist, so light output at low speeds is limited and can flicker. Additionally, the beam shape isn’t very uniform – several bright spots appear in the centre, which some riders may find distracting.

Supernova M99 DY PRO

Lumens at 20kph: 419 (high beam)
Maximum Illuminance: 200 lux
Battery For Low Speed: No
USB Charging: No
Price: US $319 on Amazon

Igaro C1 (550+ Lm)

The Igaro C1 is another ultra-bright dynamo light that excels at fast device charging. At speeds above 23 km/h (14 mph), it delivers more USB power output than any other dynamo light charger on the market.

While its beam isn’t as bright or wide as some of the other models, it offers a concentrated central hotspot and a fairly broad spread. There’s also a generous amount of low-level illumination directly in front of the wheel and to the sides, making it especially useful for low-speed riding.

What really sets the C1 apart is its high level of configurability. Using a companion app, you can fine-tune how power is distributed between lighting, charging, and storage. These settings automatically adapt based on your speed, battery level, and ambient light.

Additionally, the built-in supercapacitors supply power when you’re riding at low speeds, helping to eliminate flickering and maintain a consistent, high-lumen output.

The light is housed in a single-piece CNC-machined aluminium shell, sealed for an IP69 waterproof rating. USB-C ports and sockets come with rain covers, and the toughened front glass and vibration-resistant internals make it highly durable for demanding rides.

Igaro C1

Lumens at 20kph: 575 (both beams)
Maximum Illuminance: 80+ lux
Battery For Low Speed: Supercaps
USB Charging: Yes
Price: £317

Purple Dog Companion (300+ Lm)

The Purple Dog Companion, designed and built by Nicola Banishki, combines a light and a USB charger in one unit. A handlebar-mounted remote allows you to switch between powering external devices or illuminating your path, with adjustable power levels for each mode. Impressively, it even lets you charge devices and light your way simultaneously.

The Companion has a narrower beam compared to the other lights here, focusing more light farther down the road. This makes it better suited for higher speeds rather than slower riding. It’ll be best used on tarmac roads.

Thanks to its internal battery, it can maintain full brightness at any speed, and there’s the option to dim it down to about 20% brightness when you don’t need maximum illumination. The light is available with two LED colour options: warmer or cooler.

Purple Dog Companion

Lumens at 20kph: 225
Maximum Illuminance: 40 lux
Battery For Low Speed: 1600 mAh
USB Charging: Yes
Price: €395

B&M IQ-X (300+ Lm)

The B&M IQ-X is a popular dynamo front light known for its excellent foreground illumination, making it especially useful for slower-speed riding and cornering.

With a 300-lumen output, it excels at illuminating the road ahead over longer distances, outperforming the next three lights I’ll cover. However, this combination of strong near-field and long-range lighting creates a trade-off: a noticeable dark band between the two areas.

The IQ-X also provides good side visibility, thanks to a separate LED positioned behind side openings in the light’s housing. These LEDs remain faintly illuminated even when stationary.

Overall, the light is sturdy and well-constructed with a durable metal housing. The only minor drawback is the on/off button, which has a slightly spongy feel when pressed.

B&M IQ-X

Lumens at 20kph: 300
Maximum Illuminance: 100 lux
Battery For Low Speed: No
USB Charging: No
Price: US $129 on Amazon

B&M Lumotec IQ Cyo Premium (250+ Lm)

The Cyo Premium (80 lux version) is easily one of my top recommendations in the mid-range dynamo light category. It delivers a relatively high light output with a wide and evenly distributed beam.

While it doesn’t quite pack the punch of the B&M IQ-X, the tapering beam shape results in a more even distribution of light, which will be especially nice for road use.

B&M Lumotec IQ Cyo Premium T Senso Plus

Lumens at 20kph: 260
Maximum Illuminance: 80 lux
Battery For Low Speed: No
USB Charging: No
Price: US $102 on Amazon

SON Edelux II (200+ Lm)

The SON Edelux II dynamo light is renowned for its reliability and excellent beam shape for road use. It’s the dynamo light I’ve personally used for nearly a decade without a single issue.

It shares the same reflector as the B&M Cyo Premium, so the beam shape should look almost identical. The main differences lie in the materials and construction.

The Edelux II features an anti-reflective glass lens, unlike the plastic front panel of the Cyo Premium. This allows slightly more light to pass through and significantly reduces side-scatter, which some riders find distracting (though others appreciate the additional peripheral visibility). It also boasts a durable metal housing that’s highly waterproof, offering better long-term protection than the plastic casing of the Cyo.

In terms of beam colour, the Edelux II has a slightly warmer tone, while the Cyo Premium appears a bit cooler.

At around twice the price of the Cyo Premium, the SON Edelux II is worth the extra cost only if you value its warmer beam colour, reduced side glare, and premium build quality. For added versatility, SON also offers an upside-down lens option, allowing for under-bar or low front-rack mounting.

SON Edelux II

Lumens at 20kph: 210
Maximum Illuminance: 95 lux
Battery For Low Speed: No
USB Charging: No
Price: US $220

B&M IQ-XS (200+ Lm)

The best value dynamo light I can recommend is the B&M IQ-XS. This compact light actually offers a wider beam than the SON Edelux II and Cyo Premium, making it slightly better suited for off-road use and cornering.

Its beam shape is broad and evenly distributed at moderate speeds, starting just in front of the wheel and extending up to 15 to 20 metres. However, the wider spread means it may not provide enough illuminance for high-speed descents or demanding terrain.

The IQ-XS offers reliable everyday performance and solid build quality (including a metal housing), especially impressive given that it costs half as much as the Cyo Premium and just a quarter of the price of the Edelux II!

B&M IQ-XS

Lumens at 20kph: 210
Maximum Illuminance: 80 lux
Battery For Low Speed: No
USB Charging: No
Price: US $54 on Amazon

Best Dynamo Lights: Round Beam Shape

kLite Bikepacker Ultra V2 (1300+ Lm)

The kLite Bikepacker Ultra V2 is one of the brightest dynamo lights on this list and is designed with durability in mind. It’s fully waterproof, vibration-resistant, and built to withstand the demands of off-road riding.

Renowned for its outstanding off-road brightness, the Bikepacker Ultra is a favourite among ultra-distance racers. It provides significantly more illumination ahead and to the sides than most dynamo lights, making it ideal for slow-speed riding and tight turns. Its three horizontally mounted LEDs each contribute different characteristics, resulting in a beam that’s more oval than round.

There are two beam configurations. The ‘Race’ version (two spotlights and one floodlight) is designed to project light far down the trail, making it ideal for descending rough terrain at high speeds. In contrast, the ‘Adventure’ version (two floodlights and one spotlight) features a wider beam shape with strong foreground illumination, better suited for tackling technical terrain at slower speeds.

kLite Bikepacker Ultra V2

Lumens at 20kph: ±1000
Maximum Illuminance: -
Battery For Low Speed: Supercapacitor
USB Charging: Yes (comes in kit)
Price: US $500 (full kit)

Sinewave Beacon 2 (750+ Lm)

The Sinewave Beacon 2 is a powerful dynamo light with a round beam shape. While the light is undoubtedly bright, the beam shape is more like a narrow torch beam, so it’d actually be better for higher speed riding on tarmac roads where you don’t need to see through corners.

A key highlight is this light’s versatile power options – you can run it via a dynamo hub, an external USB battery pack, or both simultaneously. When connected to a battery pack, it also supports a blinking mode for added visibility.

It provides reliable smartphone charging at speeds of around 17 km/h, but can also power small USB devices at speeds as slow as 5 km/h.

Sinewave Beacon 2

Lumens at 20kph: 451
Maximum Illuminance: -
Battery For Low Speed: No
USB Charging: Yes
Price: US $350

Exposure Revo (800+ Lm)

The Exposure Revo is a high-quality, ultra-bright dynamo light featuring four LEDs. It reaches its maximum 800-lumen output at around 27 km/h, making it ideal for fast-paced riding.

When you come to a stop, the Revo’s supercapacitors provide up to ten minutes of light at 400 lumens. It can also continue running for up to an hour at a gradually decreasing brightness. These supercapacitors will recharge fully after just 15 minutes of riding, and help the light return to full output quickly when you’re regularly stopping and starting.

A neat feature on the back of the light is the dedicated output port for powering the Exposure RedEye rear light.

Exposure Revo

Lumens at 20kph: ±500
Maximum Illuminance: -
Battery For Low Speed: Supercapacitor
USB Charging: No
Price: US $300 on Amazon

Note: If you make a dynamo light purchase through the Amazon links, a small cut goes to supporting CYCLINGABOUT. It’s no cost to you, and the money goes a long way to creating more great resources.

My Full Dynamo Setup Series

If you want to learn it all, it could be worth digging into my full series on dynamo setups:

Dynamo Hubs
Dynamo USB Chargers
Dynamo Wiring
Buffer Batteries
Rim Dynamos

The post A Guide To The Best Dynamo Lights For Bicycle Touring and Bikepacking appeared first on CYCLINGABOUT.com.

Personally, I use the Cinq Plug6 Plus to charge a range of devices, including my iPhone, AirPods, speaker, eReader, headlamp, Insta360 camera, Garmin InReach, and a battery pack.

This article was originally published in March 2012 but has been updated in May 2025.

If you’re bikepacking off-road or tackling steep mountain trails, you might want to consider using a power bank or solar panel instead of relying solely on a dynamo charger. Dynamo systems aren’t very efficient for charging high-power devices like smartphones unless you’re maintaining an average speed of 12 to 15 kph (7.5 to 9 mph).

That said, hub dynamos are still capable of charging low-power devices such as GPS trackers, navigation units, or small battery packs – even at speeds as low as 5 kph (3 mph). This makes them a reliable option for off-road ultra-endurance racing.

If your route involves a mix of riding speeds, especially stretches where you’re often below 12 km/h, it’s a good idea to include a buffer battery in your setup. This helps keep your devices powered during slow climbs or stops, like waiting at traffic lights. Thankfully, many modern hub dynamo USB chargers now come with integrated buffer batteries.

The above is a very brief introduction – if you want to learn it all, it could be worth digging into my full series:
Dynamo Hubs
Dynamo Lights
Dynamo USB Chargers
Dynamo Wiring
Buffer Batteries
Rim Dynamos

Key Stats For Benchmarking Hub Dynamo USB Chargers

To make comparison easier, I’ve detailed the key specifications of each hub dynamo USB charger in this guide and grouped them into three distinct design categories:

• Steerer Integrated – These chargers are built to fit cleanly inside your fork’s steerer tube for a sleek setup.

• Front Light – These are dynamo-powered front lights that also function as USB chargers.

• Inline – Typically compact boxes or tubes, these chargers need to be mounted externally or carried in a bag.

The main specifications used for comparison are:

• Speed at 2.5W – The speed required to generate 2.5 watts, the baseline requirement for charging a smartphone.
• Power at 20 kph – The maximum USB output power when riding at 20 kph.
• Power Output Graph – A graph showing the charger’s power output curve, if available.
• Buffer Battery – If the charging system includes a built-in buffer battery, its capacity is noted here.
• Price – The retail price of the hub dynamo USB charger.

Within each design category, chargers are also ranked by their power output at a steady cycling speed of 20 km/h.

Integrated Hub Dynamo USB Chargers

Cinq Plug6 Plus

The Cinq Plug6 Plus is the hub dynamo USB charger I currently use, chosen for its sleek integration and strong power output at speeds below 18 kph. It includes a 1100 mAh buffer battery hidden within the steerer tube, which kicks in when your speed drops below 12 kph. The unit allows you to power lights and charge a device simultaneously, although with both running together, it’s better at maintaining a phone’s charge than fully recharging it. The USB-C port is neatly concealed beneath a rotating, ratcheting top cap.

One drawback is its limited waterproofing – water can collect inside during heavy rain. Because of this, I avoid using it in downpours and always cover it with the included waterproof cap. Also, if you’re looking for a short USB-C-to-iPhone cable, there’s a 15 cm option available on Amazon, and for USB-C to USB-C, there are 15cm options and 10 cm options.

Speed at 2.5W: 12 kph
Power at 20kph: 4.6 watts
Power Output Graph: HERE
Buffer Battery: 1100mAh
Price: US $359

Forumslader V6 Ahead

The Forumslader Ahead V6 ranks among the most powerful dynamo USB chargers at higher speeds, featuring built-in buffer batteries that ensure a stable charge even when stopped. The bigger battery requires more length inside the steerer tube (290 mm) than the smaller battery (190 mm).

A key advantage of Forumslader products is their continual updates, incorporating the latest technology and circuitry, made possible by their small-scale production. For extra protection of the USB port, an aftermarket dust- and water-resistant cap is available HERE.

Speed at 2.5W: 14 kph
Power at 20kph: 4.6 watts
Power Output Graph: HERE
Buffer Battery: 2100 or 7350 mAh
Price: €255

Cycle2Charge V3+

The Cycle2Charge V3+ dynamo USB charger provides great value for its price. It generates the minimum power required to charge a smartphone at 15 kph (2.5W), with the majority of its output occurring between 20 and 25 kph. Like the Plug6 Plus, it includes a rotating dome that protects the USB port when not in use.

Speed at 2.5W: 15 kph
Power at 20kph: 4.3 watts
Power Output Graph: HERE
Buffer Battery: No
Price: €80

Sinewave Reactor

The Sinewave Reactor is known for its solid reliability and decent performance. Its electronics are cleanly integrated into the fork steerer, giving it a sleek look and making it more resistant to theft. Made in the USA, it has earned high praise from numerous users. It’s also available in eight different anodised colours!

Speed at 2.5W: 17.5 kph
Power at 20kph: 3 watts
Power Output Graph: HERE
Buffer Battery: No
Price: US $220

Cinq Plug5 Pure

The Cinq Plug5 Pure is a more affordable option compared to the Plug6 Plus, as it doesn’t include an integrated buffer battery. Since its maximum output is only 3.1 watts, it’s better suited for low-power devices like a Garmin GPS or Spot Tracker, rather than charging a smartphone.

Speed at 2.5W: 14 kph
Power at 20kph: 3.1-watts
Power Output Graph: HERE
Buffer Battery: No, but it is designed to be used seamlessly with the Smart Power Pack II
Price: €159

Gunzel Charge Elite

The Gunzel Charge Elite is an unusual hub dynamo USB charger. Its performance from dynamo input is relatively weak, but it stands out for its ability to be externally charged at 30W and to deliver power just as quickly to a compatible device. It’s better to think of this as a fast battery bank that’s conveniently located inside the steerer tube of your bike.

Speed at 2.5W: 40 kph
Power at 20kph: 1.7 watts
Power Output Graph: HERE
Buffer Battery: 7000 mAh
Price: €170

Lights With Hub Dynamo USB Chargers

Purple Dog Companion

The Purple Dog Companion is a combined light and USB charger, designed and built by Nicola Banishki. A handlebar-mounted remote allows you to toggle between charging the internal battery and powering external devices like a phone, with adjustable power levels for each mode.

Optimised for road use, the Companion features a soft-colored LED, a cut-off beam pattern for oncoming traffic, and the ability to dim the light down to around 20% brightness, regardless of your speed. When extra brightness is needed, it can draw from its internal battery to maintain full output.

Speed at 2.5W: 15 kph
Power at 20kph: 5 watts (manufacturer claim)
Power Output Graph: No
Battery: 1600 mAh
Price: €395

Purple Dog Stalker

The Purple Dog Stalker is an even brighter light than the Companion, equipped with a high beam and automatic power management that intelligently switches between charging its internal battery and powering a USB device. It uses the same USB circuitry as the Companion.

Instead of a single LED, the Stalker features an LED matrix that emits a brighter white light and supports both road and high beam modes. In high beam mode, it delivers significantly more light above the horizon, though road-level illumination is slightly reduced compared to the Companion. A remote control lets you dim the light at any speed (~20% brightness), and the internal battery ensures maximum brightness is maintained even when you slow down or stop.

Speed at 2.5W: 15 kph
Power at 20kph: 5 watts (manufacturer claim)
Power Output Graph: No
Battery: 1600 mAh
Price: €425

SON Ladelux

The SON Ladelux is not only one of the brightest dynamo front lights on the market, but it also delivers some of the best USB charging speeds. It’s integrated USB charger enables easy charging of external devices via a magnetic port, with a status indicator conveniently located on the handlebar switch.

As for lighting performance, it boasts a powerful 150-lux low beam and an even brighter 200-lux high beam, providing outstanding visibility in all conditions. The built-in 1200 mAh buffer battery ensures the high beam remains available regardless of your riding speed, as well as power to your devices when you stop.

Speed at 2.5W: 12 kph
Power at 20kph: 4.7 watts
Power Output Graph: HERE
Battery: 1200 mAh
Price: €479

Igaro C1

The Igaro C1 is another ultra-bright dynamo light that delivers fast device charging. Above 23 km/h (14 mph), it outperforms all other dynamo lights in terms of USB power output.

What sets it apart is its exceptional configurability. Through an app, you can control how the generated power is allocated between storage, lighting, and USB output. These preferences are then automatically adjusted based on your speed, battery charge, and surrounding light conditions.

Speed at 2.5W: 13 kph
Power at 20kph: 4.5 watts
Power Output Graph: HERE
Battery: Supercapacitor
Price: £317

Spanninga Nomad

The Spanninga Nomad is by far the most budget-friendly light and USB charger combo on the market. Its compact design includes a discreetly placed USB port on the side of the lamp. Although its light output is lower at 40 lux, compared to 90 lux from B&M and 70 lux from AXA, it provides higher USB power at 20 kph than both competitors.

Speed at 2.5W: 18 kph
Power at 20kph: 3.4 watts
Power Output Graph: HERE
Battery: No
Price: US $50

Sinewave Beacon 2

The Sinewave Beacon 2 is a powerful dynamo light with a round beam pattern and an integrated USB charger. It uses the same internal electronics as the Sinewave Revolution and Reactor, providing reliable smartphone charging from around 17 kph.

A key highlight is its versatile power options – you can run it via a dynamo hub, an external USB battery pack, or both simultaneously. When connected to a battery pack, it also supports a blinking mode for added visibility.

Speed at 2.5W: 17 kph
Power at 20kph: 2.9 watts
Power Output Graph: HERE
Battery: No
Price: US $350

B&M Lumotec IQ2 Luxos

Originally launched in 2012 (so it’s a bit dated now), this 90-lux dynamo light features a built-in handlebar switch and USB charger. Its sleek, integrated design is a strong point, though its charging performance has received mixed feedback. Nonetheless, it’s a reliable dynamo light with a well-shaped beam that’s ideal for on-road use.

Speed at 2.5W: No data
Power at 20kph: No data
Battery: No
Price: US $260

AXA Luxx70 Plus

The AXA Luxx70 Plus is comparable to the Lumotec IQ2 light, featuring a handlebar switch that lets you toggle between the LED light and USB charging. Its standout advantage is the excellent price, and by all reports, it performs reliably as well.

Speed at 2.5W: No data
Power at 20kph: No data
Battery: No
Price: US $150

In-line Hub Dynamo USB Chargers

Igaro S1 Pro

The Igaro S1 Pro is a notably high-performing dynamo hub charger, especially at low speeds. It has dual USB-C ports, status indicators, and super-capacitors that add power to your device when you’re cycling at slower speeds. The S1 Pro is IP69 waterproof and mounts directly to your handlebar near the stem.

Speed at 2.5W: 14 kph (manufacturer claim)
Power at 20kph: 6.8 watts (manufacturer claim)
Power Output Graph: HERE (manufacturer claim)
Buffer Battery: Internal super-capacitors with four minutes of stationary power
Price: £260

Lumi-Con Bike Harvester PM

The Lumi-Con PM offers amazing specs for the price. It integrates up to 3500 mAh worth of batteries that can kick in when you drop to low speeds, or store any excess power for when you’ve finished your ride.

Speed at 2.5W: 15 kph (manufacturer claim)
Power at 20kph: 5.5 watts (manufacturer claim)
Power Output Graph: HERE (manufacturer claim)
Buffer Battery: 3500mAh
Price: €161

Busch and Müller K-Werk

The B&M K-Werk is a new dynamo-powered USB charger from the renowned dynamo lighting specialists at Busch & Müller. It’s one of the most powerful options available, reaching maximum output at around 20 kph. A strap mount allows it to be attached to your top tube, and its large internal battery keeps your devices charged even when you slow down or stop. At a steady 15 kph, it takes roughly 10 hours of riding to fully charge the battery.

Speed at 2.5W: 14 kph
Power at 20kph: 4.6 watts
Power Output Graph: HERE
Buffer Battery: 4900 mAh
Price: €180

Forumslader Pro V6

The Forumslader Pro V6 comes in a more budget-friendly inline version than the Ahead V6 (mentioned earlier), designed to fit neatly inside a handlebar bag. It’s one of the most powerful dynamo USB chargers at higher speeds, with built-in buffer batteries that maintain a stable output even when stationary.

A standout feature of Forumslader products is their ongoing evolution – thanks to small-scale production, they’re frequently updated with the latest technology and circuitry.

Speed at 2.5W: 14 kph
Power at 20kph: 4.6 watts
Power Output Graph: HERE
Buffer Battery: 7500 mAh
Price: €122

Fahrradlader V3.1

The Fahrradlader V3.1 is a small open-hardware project by an electrical engineering student in Germany. The Fahrradlader V3.1 delivers big power at 20kph for very little money, plus it has four supercapacitors that keep the power flowing temporarily when you ride at low speeds. This model is not waterproof and appears to only be made in small numbers (you might need to get your name on a list).

Speed at 2.5W: 16.5 kph (manufacturer claim)
Power at 20kph: 5 watts (manufacturer claim)
Power Output Graph: HERE (manufacturer claim)
Buffer Battery: Four super-capacitors with stationary power
Price: €35

Igaro D2 Pro R3

The Igaro D2 Pro R3 charger features dual USB-C ports, status indicators, and a metal casing. It’s compact, IP69 waterproof, and hand-assembled in the UK. The charger comes with a five-year warranty, and Igaro will ship warranty replacements anywhere in the world for free.

Speed at 2.5W: 14 kph (R2 model)
Power at 20kph: 4.1 watts (R2 model)
Power Output Graph: HERE
Buffer Battery: No
Price: £160

Lumi-Con Bike Harvester P5

The Lumi-Con P5 offers excellent specs for the price. It integrates up to 7000mAh worth of batteries that can store any excess power for when you’ve finished your ride.

Speed at 2.5W: 14 kph
Power at 20kph: 4 watts
Power Output Graph: HERE
Buffer Battery: 2x 3500mAh
Price: €159

Velotor Sport E2 Base

The Velotor is a compact dynamo charger that performs reasonably well at lower speeds, but really comes into its own above 30 kph. At higher speeds, like descending a mountain at 55 kph, it can deliver up to 10W of power, making it one of the highest-output USB chargers available.

Speed at 2.5W: 16 kph
Power at 20kph: 3.6 watts
Power Output Graph: HERE
Buffer Battery: No
Price: €197

Sinewave Revolution

Weighing just 38 grams and fully waterproof, this compact charger connects directly to phones or power banks. It’s a popular choice thanks to its known reliability and Sinewave Reactor-matching performance at a lower price. Expect around 2.5W at 17 kph, 3W at 20 kph, and up to 4.5W at 30 kph. Like all Sinewave products, it’s proudly made in the USA.

Speed at 2.5W: 17 kph
Power at 20kph: 3 watts
Power Output Graph: HERE
Buffer Battery: No
Price: US $120

kLite Micro

kLite, the small Australian company known for rugged lighting and dynamo systems built for remote backcountry adventures, now offers the kLite Micro – a compact, waterproof USB charger. While its power output is modest, it’s ideal for smaller devices like GPS units or trackers.

Speed at 2.5W: 18 kph (manufacturer claim)
Power at 20kph: 3 watts (manufacturer claim)
Power Output Graph: HERE (manufacturer claim)
Buffer Battery: No
Price: US $100

kLite Dual USB Charger

The kLite Dual USB charger is built with reliability in mind. It uses thicker internal cabling and smoothing capacitors to deliver ultra-consistent power, ideal for direct charging of sensitive devices (according to kLite, these components take up nearly half the unit’s volume). It also features dual USB output ports and an input for a solar panel, making it one of the most versatile options available.

Speed at 2.5W: 18 kph
Power at 20kph: 2.8 watts
Power Output Graph: HERE
Buffer Battery: Available separately
Price: US $170

Busch and Müller E-Werk

Though somewhat dated, the E-Werk is notable for letting you adjust both voltage (2.8 to 13.3V) and current (0.1 to 1.5A) to suit the charging needs of various devices. While this flexibility sounds promising in theory, it can make the charger more complex than necessary. This feature is only beneficial if you frequently ride at very high speeds (over 40 kph). In terms of performance, the E-Werk delivers smartphone-level charging at around 17.5 kph and exceeds 7 watts by the time you reach 45 kph.

Speed at 2.5W: 17.5 kph
Power at 20kph: 2.8 watts
Power Output Graph: HERE
Buffer Battery: Available separately for €105
Price: €179

Busch and Müller USB-Werk

The USB Werk is Busch and Müller’s newer model, though it’s becoming a bit dated itself. It’s a simplified version of the E-Werk, featuring a small built-in buffer battery. It can deliver smartphone-level charging (around 2.5 watts) at 20 kph.

Speed at 2.5W: 20 kph
Power at 20kph: 2.5 watts
Power Output Graph: HERE
Buffer Battery: 300mAh
Price: €110

USB2BYK

Speed at 2.5W: 20 kph (manufacturer claim)
Power at 20kph: 2.5 watts (manufacturer claim)
Buffer Battery: No
Price: €39

Kemo M172N

The Kemo M172N is a dynamo USB charger featuring a built-in switch that lets you toggle power between your lights and USB devices. It’s a great value and reportedly performs very well when your average speed stays above 25 kph.

Speed at 2.5W: 22 kph
Power at 20kph: 2.3-watts
Power Output Graph: HERE
Buffer Battery: No
Price: £40

PowerBUG

Another affordable charger from Poland is the PowerBUG. Although it requires relatively high speeds to reach smartphone-level charging, it’s definitely budget-friendly.

Speed at 2.5W: 25 kph
Power at 20kph: 2.3 watts
Power Output Graph: HERE
Buffer Battery: No
Price: €38 (169 zł)

Ullmann Power Station 4

Speed at 2.5W: No data
Power at 20kph: No data
Buffer Battery: No
Price: €130

VeloCharger MK2

Speed at 2.5W: No data
Power at 20kph: No data
Buffer Battery: No
Price: £105

BioLogic ReeCharge Dynamo Kit

Speed at 2.5W: No data
Power at 20kph: No data
Buffer Battery: No
Price: US $39

Learn About:
Hub Dynamo USB Chargers HERE
Dynamo Wiring Systems HERE
Buffer Batteries HERE
Dynamo Lights HERE

The post List of Hub Dynamo USB Chargers That Power Your Electronics While You Ride appeared first on CYCLINGABOUT.com.

This new test paired four dynamo hubs with various lights and USB chargers, measuring performance across speeds from 0 to 30 km/h. The results were surprising, revealing just how much performance can vary, even among hubs all rated at 6 volts and 3 watts.

The SON 28 Classic dynamo hub, which has long been used for the majority of all dynamo light and USB charger benchmark tests over the years, now lags behind the performance of newer SON hub models. And that performance gap has real-world implications, especially when it comes to charging your devices or lighting your way.

Let’s dive into the details.

Hub Dynamo Lab Test

Andreas Oehler tested four different SON hub dynamo models for FahrradZukunft:

• SON 28 Classic: Standard 6V 3W dynamo hub
• SONdelux 12: Dynamo hub for high-speed use
• SON 28 12: Most powerful current SON hub
• SON 29 S: New 40 magnetic pole dynamo hub

These four hubs were connected to three different dynamo lights and USB chargers:

• SON Ladelux: All-new light and USB charger from SON
• B&M E-Werk USB Charger: Powerful new charger from Busch & Müller
• Supernova M99 DY Pro: Super bright dynamo light from Supernova

Method

The various SON dynamo hubs were mounted in the FahrradZukunft test rig and spun at different speeds.

The setup assumed a 28″ wheel with a 700 mm diameter. Electrical output from the hub, along with the charge and discharge power of the charging adapter’s buffer battery, was measured using a GMC Metrahit 29S. A programmable electronic load (Array 3711A) simulated the USB power draw.

Once everything was in place, drive power was calculated based on the measurements.

You can see the full test over at FahrradZukunft.

Results: SON Dynamo Hub Output Power

The graph above compares the four SON hubs when paired with various lights and USB chargers. Speed (in km/h) is shown along the horizontal axis, while power output (in watts) is displayed on the vertical axis.

For context, the minimum power required to charge a smartphone is around 2.5 watts. And most smartphones need between 3 and 4 watts to keep the screen fully lit during navigation.

While the graph offers valuable insights, I’ve broken down the power differences in percentage terms in the tables below, using the SON 28 Classic as the baseline. This makes it easier to see just how much more (or less) powerful each hub is in comparison.

SON Ladelux Light & USB Charger

Whether you’re charging devices or powering lights, the SON 29 S consistently outperforms the SON Classic across all speeds, delivering 40 to 57% more power, with the most significant gains at lower speeds. This translates into a noticeable improvement in real-world use: you’ll reach the 2.5 W minimum charging specification for a smartphone by just 5 km/h, and over 6 watts by 15 km/h!

The SON 28 12 is slightly less powerful than the SON 29 S but still offers a substantial upgrade, with a 27 to 39% power increase over the Classic. As a result, it reaches the minimum charging threshold for a smartphone (2.5 watts) about 4 km/h sooner than the Classic.

As expected, the SONdelux produces less power across all speeds, but it remains close behind the SON Classic throughout the range.

B&M K-Werk USB Charger

When charging with the K-Werk at 10 km/h, the new SON 29 S delivered its strongest performance, producing 125% more power than the SON Classic. That’s right, 11 km/h is all the speed you need to achieve 4 watts of power, which provides a decent charge for most smartphones. While the hub’s power output remains impressive at 15 km/h, it has fully plateaued by 20 km/h.

The SON 28 12 also shows a solid improvement at lower speeds, offering 28 to 38% more power than the Classic. However, like the SON 29 S, its output levels off around 20 km/h.

Interestingly, while the SONdelux produces about 12% less power than the SON Classic at lower speeds, it overtakes all other hubs by the time you reach 30 km/h – delivering the highest USB charging output in the test.

Supernova M99 DY Pro Light

Shifting focus from USB charging to lighting, let’s look at the Supernova M99 DY Pro dynamo headlight.

At 10 km/h, the SON 29 S delivers 75% more power than the SON 28 Classic, and this results in a significantly brighter beam and reduced flickering. Even at 20 km/h, the 29 S still provides nearly 50% more power than the Classic.

The SON 28 12 offers more modest gains, delivering between 10% and 44% more power than the SON Classic, or roughly half the improvement seen with the SON 29 S.

As expected, the SONdelux lags behind in output. It produces less power than the SON Classic across the board, resulting in a dimmer beam (especially at lower speeds). At 10 km/h, it delivers only about half the power of the SON 29 S, making the difference in brightness quite noticeable.

SON Dynamo Hub Comparison

Recent dynamo hub testing indicated that the new Shimano hub could produce more power (especially between 5 and 15 km/h), but I hadn’t realised how much variation there is among SON hubs too.

Running an average across all tests and speeds:

• The new SON 29 S delivered 45% more power than the SON 28 Classic
• The SON 28 12 was 24% more powerful than the SON 28 Classic
• The SONdelux was 6.3% less powerful than the SON 28 Classic

More power means brighter lights or stronger device charging at a given speed. But keep in mind, it also results in increased drag, which can slow you down.

Or to put it another way: the power the SON Classic generates at 15 km/h can be matched by the SON 28 12 at just 12 km/h, and by the SON 29 S at only 10 km/h. In contrast, the SONdelux would require you to travel at 16 km/h to achieve the same output.

Which SON Hub Dynamo Is The Best?

The best SON dynamo hub for you depends on how and where you ride.

For off-road adventures and bicycle touring, where strong lighting and USB charging at low speeds are essential, the SON 29 S or SON 28 12 are your top choices.

The new, high-output SON 29 S is especially impressive, generating 4 watts at just 11 km/h when paired with either the SON Ladelux or K-Werk USB chargers. At the same speed, it can also power the M99 DY Pro’s high beam mode without flickering.

For road and gravel riding, where average speeds tend to be higher, the SON 28 Classic or SONdelux will be more than adequate.

With either the Ladelux or K-Werk USB chargers, both hubs hit the minimum charging specification for a smartphone at approximately 11 to 13 km/h. And by 15 to 16 km/h, they’re producing around 4 watts, which is enough power to keep a smartphone screen continuously powered for navigation.

How Do SON Dynamo Hubs Compare To Other Hubs?

Previous testing has revealed significant differences in dynamo hub power output.

When paired with a kLite USB charger, Shimano hubs produced 30 to 60% more power than the SON Classic at speeds between 15 and 20 km/h. In contrast, the SP dynamo hub delivered 6 to 47% less power than the SON Classic under the same test conditions.

While the current testing uses a different protocol and equipment (making direct comparisons difficult), we can reasonably expect the SON 28 12 to match or outperform the Shimano 3D32, and the SON 29 S to exceed the output of the Shimano UR700.

Summary

This test highlights the significant differences in power output between various SON dynamo hubs.

On average, the new SON 29 S delivers 45% more power than the SON 28 Classic, while the thru-axle versions of the SON 28 offer a 24% boost.

For cyclists who typically ride below 15 km/h, especially on long-distance tours or bikepacking trips, a higher-output dynamo hub is well worth considering if consistent USB charging or bright lighting is a priority.

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The post The New SON 29 S Dynamo Hub Generates 45% MORE Power (Lab Test) appeared first on CYCLINGABOUT.com.

I will be explaining how different USB chargers and dynamo hubs will affect the charge rate. We will look at the charge rates both at constant speeds (easy to predict), as well as at varying speeds (hard to predict).

I will also be describing the complexity of predicting charge times on a smartphone (super hard to predict) using some newly available data.

This article is very graph and data-heavy, so hats off if you can digest it all the first time around. Please remember, you can always skip through to the summary at the end if you just want to extract the key points.

Terminology: Volts, Amps, Watts, mAh

To understand this article well, let me briefly explain a few terms.

The voltage (in volts or ‘V’) and current (in amps, or ‘A’) make up the total electrical system power.

I won’t go into too much detail about what these are, but here’s what you should know: the output voltage (V) of a dynamo is fixed (mostly). Almost all dynamo hubs are designed to put out 6-volts in AC power, and once we convert this to the DC power necessary for charging things – we end up with around 5-volts.

It’s the current (A) that fluctuates most in a dynamo charging system. At low speeds, the current will be less than 0.1-amps, and at high speeds, it can be more than 2-amps.

If you didn’t understand that, don’t worry. The most important term to remember is watts, which is the total output power. I will be using watts to benchmark different chargers and hubs throughout this resource.

We get watts simply by multiplying the volts and the amps together. For example, a dynamo hub putting out 5-volts at 1.1-amps will provide 5.5-watts at the USB plug (5V x 1.1A = 5.5W).

And lastly, I’m using milliamp hours, or mAh, when I’m referring to both battery energy capacity and charging rates. You will always find the total energy capacity (in mAh) written on the battery.

Calculating Dynamo Charging Rates

The simplest way to calculate how quickly a dynamo hub can charge devices is to look at a power curve graph. By picking a speed that you often find yourself cycling, you can determine the amount of power available at the USB plug, and the associated charging rate.

Example: 15kph with the Forumslader V5 Ahead Charger
When we follow the light blue Forumslader V5 graph line up to 15kph, we can see it’s producing 3-watts of power. As the voltage is fixed at 5-volts on a dynamo, we can calculate the current to 0.6A, which for an hour of riding is 600mAh. This would mean that when charging my Petzl CORE 1250mAh headlamp battery, it would fill from empty in 2 hours and 5 minutes.

Example: 15kph with the PedalCell Rim Dynamo Charger
The PedalCell (dark blue) is producing over 5-watts (5V and 1.04A) at 15kph, which for an hour of cycling translates to 1040mAh. It would fill my Petzl CORE 1250mAh headlamp battery from empty in 1 hour and 12 minutes.

Note: the data here has been recorded in 5kph intervals. To get a more accurate power output prediction, you should round up or down to the nearest 5kph of what you ride. This is because, in reality, USB chargers offer power in ‘steps’ – you’ll soon visualise this in the section Battery Charging With Varying Speeds.

Battery Storage Losses

The calculations we’ve just made have assumed that all power is going directly to your device. But what if you’re charging into a battery so that you can save the power for later?

When power is stored in a battery, it experiences a storage loss of around 15-20%. This essentially means that you will need to cycle for 15-20% more time to get the same amount of energy to your device.

Using the same examples as previously: if I stored the energy in a battery first, my Petzl battery would require 2 hours and 30 minutes of cycling to fill (Forumslader V5 charger @ 15kph). And I’d need to ride for 1 hour and 26 minutes to fill my Petzl battery, using a PedalCell rim dynamo charger.

Charging Differences Between Dynamo Hubs and USB Chargers

The power curve we previously looked at showed the differences in power available between different USB chargers. But how do dynamo hubs differ in power output?

It turns out, quite a bit…

Example: 15KPH with the Shimano UR700 hub
When we pair the UR700 with the kLite USB charger, the power available is 3-watts (5V and 0.6A), which translates to 600mAh. It would take 2 hours and 5 minutes to charge my Petzl headlamp battery with this combination.

Example: 15KPH with the Schmidt SON28 hub
If we instead use a Schmidt hub with the kLite USB charger, we’d get 1.9-watts (5V and 0.38A), which translates to 380mAh. This means that the charge time on my 1250mAh Petzl battery would be over three hours… or a 36% time difference between hubs.

When we look at the Shimano UR700 data across four different USB chargers, we can see 20-50% more power available at any given speed. While the data is limited to only four chargers, it’s quite likely that this hub will bring a significant boost in power to any dynamo charging setup.

But there is a downside to the UR700 hub – it’s more inefficient than other hubs. The amount of drag it experiences at the wheel is often 2-3x higher than the Schmidt hub, which can really add up to slow you down.

You can read more about dynamo hub drag HERE.

USB Charger Testing With Varying Speeds

While the graphs in the previous sections have given us an idea of the power output at very specific speeds, on undulating terrain, it’s unusual to cycle at a constant speed for long periods of time.

To help simulate undulating riding conditions, Fahrrad Zukunft created a dynamic test with varied cycling speeds to see which dynamo USB chargers could generate the most power.

The test is a little over the top in speed variation, but it’s still pretty interesting to see that some USB chargers are able to adapt to changes in speed better than others.

The test protocol had the cycling speed in 2-second steps from 10kph up to 30kph and then back down to 10kph again. The accelerations between steps took 3-seconds. This 20-minute test essentially exposes the responsiveness of the USB chargers, which are constantly trying to optimise the charging rate.

Output power at the USB port after 20 minutes:
1. Forumslader V5 (1200mWh or 240mAh)
2. Lumi Con P5 (1000mWh or 200mAh)
3. Plug5 Plus (1000mWh or 200mAh)
4. NC-17 Appcon 3000 (900mWh or 180mAh)
5. USB Werk (600mWh or 120mAh)
6. Zjego (400mWh or 80mAh)

Expectedly, the USB chargers with the highest power outputs did the best in this test, although the Lumi Con P5 is a standout because it offers less output power than the other chargers in the top-four, yet still manages to extract a decent charge thanks to how well it handles changes in speed.

Battery Charging With Varying Speeds

PedalCell has recently conducted a lab test (with CyclingAbout contributions ) to see how their rim dynamo deals with changes in cycling speed. You can read a copy of their white paper HERE.

This data is interesting because it shows how the charger constantly optimises the amount of power available at the USB port at different speeds. This is important to understand because it shows that power is delivered to your battery/device in ‘steps’ – not in the way it is depicted in the FahrradZukunft graphs above.

For the PedalCell, at least, the data suggest that around 2mph/3kph is enough to trigger a change in charge rate.

By extracting the power and time information from this graph, we can roughly calculate how much charge the PedalCell can put into a battery pack if you were cycling on undulating terrain (50-second descent followed by a 10-second climb x 60).

If you were riding the same course as the lab test, you could expect 1583mAh per hour. Those are really big numbers for a bicycle dynamo on lumpy terrain!

The Complexity of Calculating Smartphone Charging Rates

One of the most common devices that people charge on bike trips is a smartphone, but here’s the deal: it’s hard to predict charge times on a smartphone because the charging software chooses the charging rate, and there is a lot of variation between software.

The battery percentage is one factor that affects the charge rate of a smartphone – most will allow quick charging when a battery is empty, but will reduce the charge rate as you get closer to 100%.

Another factor is whether the screen is on or off. When the screen is on, a smartphone will usually accept more power than when your phone is on standby.

The apps that you’re using on your smartphone can also affect the charging rate.

And lastly, the dynamo USB charger that you’re using should also support the appropriate USB charging protocols for your smartphone. There are dozens of protocols that have been created by governing bodies and private companies to safely draw the maximum amount of power. If your charger is not using the suitable charging protocol for your smartphone, it may not achieve its full charging rate.

In some cases, smartphones do not charge well from a dynamo because the charging software thinks it is receiving power from a faulty wall charger, resulting in a significant throttling of the charge rate.

One reader has informed me that their Motorola smartphone charges at just 0.3A (1.5-watts) no matter the cycling speed, even though their B&M USB Werk charger should be putting out 0.7A (3.5-watts).

The work-around for this software limitation is to simply charge into a power bank first, before sending the power to your smartphone. Unfortunately, this reader will now have the abovementioned battery storage losses, but they will also get twice as much charge going into their smartphone!

Smartphone Charging With Varying Speeds

Ok, onto the smartphone charging data.

PedalCell conducted a lab test with three different smartphones to see how well their charger would negotiate with the smartphone software to optimise charge speeds. They tested the charging rates of these smartphones with the screen both on and off – I’m using the screen-on data for this resource.

The batteries were all at 40-50% charge – keep in mind that a smartphone tends to charge quickly here, so you will not get the same test results at 80% charge.

To get a sense of an iPhone XR’s charging speed using the PedalCell on hilly terrain, we can extrapolate the data from the graph (30-second descent followed by a 15-second climb x 80).

I’ve calculated that the charging rate is 1666mAh per hour (57% of the battery capacity) on this specific riding course.

The PedalCell has very little negotiation time when charging the One Plus 8 Pro, showing this smartphone to charge in a similar manner to the 10400mAh battery.

So, does that mean it will be getting more charge when compared to the iPhone XR?

When we run the numbers here, the One Plus is getting around 1578mAh per hour into its battery, which is about 35% of its battery capacity. While the negotiation times are quick, the peak charge rate is a little lower than the iPhone, which means that it’s not quite picking up the same amount of charge at higher speeds.

Riding course: 50-second descent followed by a 20-second climb x 51

The Google Pixel (2016) had the lowest charge rate of the smartphones tested.

Interestingly, the Pixel’s software chose to fluctuate the current quite a bit compared to the other phones. PedalCell has suggested it could be because the battery was 4-5 years old, but when we look at the charging rate of the Pixel 2 XL from a wall charger, the phone’s charging rate likely fluctuated out of the box.

Despite a lower peak charging rate of around 8.5-watts, the Google Pixel was still able to charge at 1362mAh per hour, which is 49% of the battery capacity.

Riding course: 38-second descent followed by a 22-second climb x 60

Summary

This topic is a bit of a minefield, so if you’ve read the whole thing – congratulations!

At constant speeds, it’s relatively easy to predict how quickly a dynamo USB charger will fill a regular battery. We can simply look at the FahrradZukunft power output graphs to calculate how much charge per hour is possible. The graphs also indicate that some dynamo USB chargers offer substantially more power than others at different speeds.

Dynamo hubs also seem to offer a surprisingly large difference in charging performance. We can see that the Shimano UR700 has 20-50% more power available than other hubs at any given speed, although, the Skjegg data suggest that this hub has a high amount of drag for the power it offers.

Calculating charge times gets much more complicated when you’re riding in hilly terrain, as some USB chargers are more effective at varying speeds than others. As a general rule, however, the most powerful chargers will extract the most charge from your dynamo.

And finally, charging smartphones.

I wish I could give you a charge time on smartphones, but there are just too many factors to account for.

As we’ve seen with the three smartphones in the PedalCell test, the charging software plays a large role in determining the charging rate. The battery percentage is another factor, where lower percentages usually have the highest charging rates. Whether your screen is on or off, and what app you’re using will affect the charge rate too.

Thanks to PedalCell for collecting the data on charging batteries and smartphones at different speeds so that we can better understand dynamo charging! You can check out how the PedalCell rim dynamo produces more power than a hub dynamo, and at a higher efficiency HERE.

Learn About Dynamo USB Chargers HERE, Dynamo Hubs HERE, Dynamo Wiring Systems HERE, Pass-Through Batteries HERE and Dynamo Lights HERE

The post Lab Test: How Quickly Can You Charge A Battery or Smartphone With A Dynamo? appeared first on CYCLINGABOUT.com.

You will often hear remarks like ‘my dynamo hub doesn’t slow me down at all’. While it may not feel that way, there is always a cost when it comes to bicycle power production, and today, I’ll tell you how much dynamo drag will likely slow you down.

Finding the exact number is surprisingly tricky. It depends on dozens of factors including (but not limited to) rider weight, fitness level, bike weight, wheel size, tyre width, road surfaces, cycling speed – and the specific hub, charger and lights that are fitted to your bike.

To get a sense of the drag, I will be creating two different rider scenarios and running them on both flat and 5% road gradients. We will then calculate the speed differences of both the highest and lowest-drag hubs when paired with different USB chargers and dynamo lights.

Let’s start with a quick overview of the dynamo components.

The Components That Make A Dynamo Setup

Hub Dynamo
Hub dynamos generate power by passing magnets over a copper coil, and it is here where the physical drag occurs. Hubs actually vary a surprising amount in terms of both power output and efficiency, you’ll be able to see the lowest-drag hubs on some graphs below.

USB Chargers
USB chargers convert the power from your hub into a useable form at the USB plug. Depending on how the electronics have been designed, there are power output and efficiency differences here too. But importantly, the resistance at the wheel is based on how much power your plugged-in device is drawing from the hub, and this can vary quite a bit. For example, a Garmin GPS at 25KPH would likely have 6 or 7x less resistance than a big smartphone.

Dynamo Lights
When it comes to lighting, brighter lights will typically slow you down more than dimmer lights. Most dynamo lights achieve their maximum brightness (and therefore drag) between 15 and 20KPH. Personally, I think lighting is the number one reason someone should use a dynamo setup – they’re just so convenient.

My Two Cyclists

For today’s estimations, we will look at two different rider scenarios.

The smaller rider weighs 60kg and their bike plus gear is 25kg. As the average cyclist pedals at around two watts-per-kilogram on a long ride, this rider will be pushing 120-watts for the simulation.

The bigger rider is 90kg and their bike plus gear is also 25kg. They will pedal their bike at 180-watts.

Dynamo Drag Data And Calculations

I am using dynamo power and drag data collected on Skjegg Blogspot. You can find links to the original test HERE and my interpretation of the results HERE.

I have then used Bike Calculator to determine the speed differences at different power outputs. Through my own real-world testing, I have found this tool to work with very high accuracy.

Hub Dynamo With Nothing Connected

Let’s start with the hub drag with nothing connected. This graph shows the drag of four different dynamo hubs at speeds between 5 and 30KPH. You will notice that most hubs increase in resistance the faster you go; the exception is the Schmidt SON28 which has some black magic going on to achieve a somewhat steady drag at different riding speeds.

Speed difference on the flat:
Smaller cyclist with no dynamo hub – 21.70KPH
Smaller cyclist with the lowest-drag hub – 21.61KPH – 0:14 behind per hour (0.4% slower)
Smaller cyclist with the highest-drag hub – 21.37KPH –  0:54 behind per hour (1.5% slower)
Bigger cyclist with no dynamo hub – 24.62KPH
Bigger cyclist with the lowest-drag hub – 24.56KPH – 0:07 behind per hour (0.2% slower)
Bigger cyclist with the highest-drag hub – 24.32KPH – 0:43 behind per hour (1.2% slower)

Speed difference on a 5% climb:
Smaller cyclist with no dynamo hub – 7.77KPH
Smaller cyclist with the lowest-drag hub – 7.71KPH – 0:29 behind per hour (0.8% slower)
Smaller cyclist with the highest-drag hub – 7.68KPH – 0:43 behind per hour (1.2% slower)
Bigger cyclist with no dynamo hub – 8.64KPH
Bigger cyclist with the lowest-drag hub – 8.59KPH – 0:22 behind per hour (0.6% slower)
Bigger cyclist with the highest-drag hub – 8.56KPH – 0:32 behind per hour (0.9% slower)

Note: for my comparisons, I am subtracting the expected drag of a high-quality hub from all rider scenarios – that’s 0.25-watts at low speeds, 0.5-watts at high speeds.

Hub Dynamo With A Light Connected

For this scenario, we’ll be looking at how much a very bright 100lux dynamo light will slow you down. I have selected the data from the B&M IQ-X, which is one of the brightest options available and one that I personally recommend.

Speed difference on the flat:
Smaller cyclist with no dynamo hub – 21.70KPH
Smaller cyclist with the lowest-drag hub – 20.75KPH – 2:38 behind per hour (4.4% slower)
Smaller cyclist with the highest-drag hub – 20.39KPH – 3:36 behind per hour (6.0% slower)
Bigger cyclist with no dynamo hub – 24.62KPH
Bigger cyclist with the lowest-drag hub – 23.89KPH – 1:48 behind per hour (3.0% slower)
Bigger cyclist with the highest-drag hub – 23.64KPH – 2:24 behind per hour (4.0% slower)

Speed difference on a 5% climb:
Smaller cyclist with no dynamo hub – 7.77KPH
Smaller cyclist with the lowest-drag hub – 7.53KPH – 1:52 behind per hour (3.1% slower)
Smaller cyclist with the highest-drag hub – 7.28KPH – 3:47 behind per hour (6.3% slower)
Bigger cyclist with no dynamo hub – 8.64KPH
Bigger cyclist with the lowest-drag hub – 8.40KPH – 1:41 behind per hour (2.8% slower)
Bigger cyclist with the highest-drag hub – 8.16KPH – 3:22 behind per hour (5.6% slower)

Note: for my comparisons, I am subtracting the expected drag of a high-quality hub from all rider scenarios – that’s 0.25-watts at low speeds, 0.5-watts at high speeds.

Hub Dynamo With A USB Charger Connected

We will be using a kLite USB charger for this example, and we will be assuming that your device is consuming all power available at the USB port. Keep in mind that hub dynamos also vary in power output at the same speed – more power results in more drag. As the Shimano UR700 provides 25% more power at the USB plug than the SON hub, this is not a perfectly fair comparison.

On the 5% climb, I cannot simulate the SON28 as it’s not yet making good power with the kLite charger, so we will compare the two Shimano hubs instead.

Speed difference on the flat (UR700 vs SON28):
Smaller cyclist with no dynamo hub – 21.70KPH
Smaller cyclist with the lowest-drag hub – 21.15KPH – 1:30 behind per hour (2.5% slower)
Smaller cyclist with the highest-drag hub – 20.66KPH – 2:53 behind per hour (4.8% slower)
Bigger cyclist with no dynamo hub – 24.62KPH
Bigger cyclist with the lowest-drag hub – 24.13KPH – 1:12 behind per hour (2.0% slower)
Bigger cyclist with the highest-drag hub – 23.66KPH – 2:20 behind per hour (3.9% slower)

Speed difference on a 5% climb (UR700 vs 3D32):
Smaller cyclist with no dynamo hub – 7.77KPH
Smaller cyclist with the Shimano 3D30 hub – 7.76KPH – 0:04 behind per hour (0.1% slower)
Smaller cyclist with the Shimano UR700 hub – 7.46KPH – 2:24 behind per hour (4.0% slower)
Bigger cyclist with no dynamo hub – 8.64KPH
Bigger cyclist with the Shimano 3D30 hub – 8.61KPH – 0:11 behind per hour (0.3% slower)
Bigger cyclist with the Shimano UR700 hub – 8.38KPH – 1:48 behind per hour (3.0% slower)

Note: for my comparisons, I am subtracting the expected drag of a high-quality hub from all rider scenarios – that’s 0.25-watts at low speeds, 0.5-watts at high speeds.

Bonus: Predicting Time Loss With A More Powerful USB Charger

I personally use a Cinq Plug5 Plus USB charger and Schmidt SON28 hub dynamo on my bike, so I’m running these predictions more for my own curiosity than anything else.

Using the Schmidt hub charging efficiencies from the kLite graph above and the power output figures of the Plug5 Plus from some other independent testing, I can crunch the numbers to try to predict what my more powerful USB charger will likely cost our two simulated riders.

Speed difference on the flat:
Smaller cyclist with no dynamo hub – 21.70KPH
Smaller cyclist with the Schmidt SON28 hub – 20.89KPH – 2:13 behind per hour (3.7% slower)
Bigger cyclist with no dynamo hub – 24.62KPH
Bigger cyclist with the Schmidt SON28 hub – 23.98KPH – 1:34 behind per hour (2.6% slower)

Speed difference on a 5% climb:
Smaller cyclist with no dynamo hub – 7.77KPH
Smaller cyclist with the Schmidt SON28 hub – 7.57KPH – 1:34 behind per hour (2.6% slower)
Bigger cyclist with no dynamo hub – 8.64KPH
Bigger cyclist with the Schmidt SON28 hub – 8.48KPH – 1:08 behind per hour (1.9% slower)

Drag/efficiency figures for these calculations:
kLite efficiency @ 24.6KPH = 59.7% —–> Cinq Plug5 Plus @ 24.62KPH = 5.2-watts —–> Drag is 8.7-watts
kLite efficiency @ 21.7KPH = 57.4% —–> Cinq Plug5 Plus @ 21.70KPH = 4.8-watts —–> Drag is 8.4-watts
kLite efficiency @ 8.64KPH = 28.6% —–> Cinq Plug5 Plus @ 8.64KPH = 0.95-watts —–> Drag is 3.3-watts
kLite efficiency @ 7.77KPH = 28.6% —–> Cinq Plug5 Plus @ 7.77KPH = 0.95-watts —–> Drag is 3.3-watts

How Much Does Dynamo Drag Slow You Down?

The most-efficient hub will slow you down:
10-30 seconds per hour with no lights or chargers attached
1-2 minutes per hour with a USB charger
1.5-2.5 minutes per hour with a bright light

The least-efficient hub will slow you down:
0.5-1 minute per hour with no lights or chargers attached
2.5-3 minutes per hour with a USB charger
2.5-4 minutes per hour with a bright light

Hub dynamos run well with nothing connected. On the flat, my Schmidt hub is probably slowing me down only 7-seconds per hour.

When charging a smartphone, I am likely losing around 1.5 minutes per hour, which I think is very reasonable given how convenient it is to always have power on tap. A low-power device like a Garmin GPS would likely cost me around 20 seconds per hour in comparison.

That said, dynamo lights are my number one reason for using a dynamo setup, and I’m happy to lose a couple of minutes per hour at night for sheer convenience. But if I was ultra racing at the pointy end of the field, this data would make me consider whether I can get by with battery-powered lights, as I could potentially save 25-40 minutes in an overnight push – which is a decent nap!

When an ultra course allows for it, less bright dynamo lights could be a better option. The B&M Cyo, which is half the brightness of the light we simulated (B&M IQ-X), would probably cost around a minute per hour when paired with the Schmidt SON28 hub.

You Can See All Of My Dynamo Resources Listed HERE

The post How Much Do Hub Dynamos Really Slow You Down? appeared first on CYCLINGABOUT.com.

It’s fair to say those were the dark ages of bike-powered electricity. But things have come a long way. As of 2020, if you’re looking to generate power from your bike, the most efficient and powerful option available is actually a modern rim dynamo.

In this guide, we’ll explore the advantages and drawbacks of today’s rim dynamos—and take a close look at the latest performance data to see how they really stack up.

How Do Rim Dynamos Compare to Hub Dynamos?

Advantages

• You can fully disengage a rim dynamo when it’s not in use, unlike hub dynamos, which still create 1–5 watts of drag even when disconnected.

• If the dynamo fails, there’s no need to rebuild a wheel; just remove or replace the unit.

• Installation is quick and easy, and you can remove it when not needed or swap it between bikes.

• The most powerful rim dynamos can generate 40 to 70% more power than hub dynamos.

• They’re also 10 to 20% more efficient than the best hub-based charging systems.

• And when it comes to weight, the lightest rim dynamos come in over 200 grams lighter than a typical hub dynamo setup.

Disadvantages

• Potential for slippage at speeds above 25 km/h, mainly if your device is drawing a lot of power.

• Rim dynamos are generally noisier than hub dynamos (hear for yourself HERE).

• O-rings need regular replacement, typically every 3,000 to 7,000 km.

• Performance may suffer in harsh conditions, especially with heavy rim contamination like thick mud.

• The most powerful and efficient models tend to sacrifice elegance in design.

• Compatibility is limited; only a few dynamo lights and two USB chargers currently work with these systems.

• At higher speeds, drag can increase significantly if your connected device is drawing substantial power (more details on this below).

Rim Dynamo Products

PedalCell Rim Dynamo and Charger Kit

US $299 and 450 grams

This three-phase rim dynamo is a dedicated charging system that includes everything you need to turn your bike into a mobile power station.

At the heart of the kit is the “Smart Power Hub,” which mounts neatly to your stem and features two USB-C ports: a “safety” port capped at 3 watts, and a “high-power” port capable of delivering over 10 watts.

Inside, a bank of supercapacitors ensures a stable power output—and even keeps your device powered for up to 30 seconds after you come to a stop.

Update: As of January 2024, PedalCell ceased operations, and their rim dynamo kits were no longer available on the market. The company cited declining demand and supply chain challenges as reasons for the closure. While some units may still be found through secondhand channels, official support and warranty services are no longer provided.

Velogical Special 3-Phase Rim Dynamo and Charger

€365 and 180 grams

Velogical’s new three-phase rim dynamo is purpose-built for low-speed riding and charging, offering greater versatility than the PedalCell.

Unlike the PedalCell, it supports both charging and powering dynamo lights simultaneously. There are two compatible charging options: the Velogical Universal Power Source and the aftermarket Forumslader for Velogical, both of which include buffer batteries to ensure a steady power supply, even when you stop at traffic lights.

In addition to its functionality, the system stands out for its sleek design, ultra-compact size, and impressively low weight, less than half that of a comparable PedalCell setup.

You can see the Velogical Rim Dynamo and Charger on the Velogical website.

The Test

Olaf Schultz and Andreas Oehler from FahrradZukunft have done the hard work to make this data available. Using their custom rear triangle test rig, they’re able to accurately measure torque, speed, and all key electrical metrics—voltage, current, power output, and more.

If you’d like to know more, the test rig is described in detail in the article, “Current rim rotor dynamos in the laboratory test”.

How Much Power Can A Rim Dynamo Generate?

The PedalCell delivers substantially more power than any other USB charging system tested, producing 42–70% more output than the top-performing hub dynamo setup (the Schmidt SON28 paired with the Forumslader V5).

What really sets the PedalCell apart is its low-speed performance: it starts delivering 2.5 watts at under 9 km/h, making it ideal for slower riding conditions.

Meanwhile, the Velogical rim dynamo combined with the Forumslader USB charger is slower to ramp up, but once you reach 15 km/h, it begins to outperform the best hub dynamo setup, though with a more modest 10% power gain.

You can see the full FahrradZukunft results HERE.

The Best Hub Dynamo Charging System:
1.7-watts @ 10 km/h
3.4-watts @ 15 km/h
4.8-watts @ 20 km/h
7.0-watts @ 25 km/h

PedalCell Rim Dynamo:
2.9-watts @ 10 km/h – 70% more power
5.2-watts @ 15 km/h – 53% more power
7.3-watts @ 20 km/h – 52% more power
10-watts @ 25 km/h – 42% more power

Note: The PedalCell and Velogical rim dynamos used in this test were pre-production units provided by the manufacturers. I’ve been in contact with both companies, and each claims performance improvements over the already impressive results seen here. Velogical, for example, states that their Universal SQ charger is expected to deliver around 4 watts at 15 km/h and up to 7 watts at 20 km/h. You can see the Velogical power curve HERE.

Are Rim Dynamos Efficient?

Dynamo efficiency measures how much power you get relative to the drag it creates while you pedal. There’s no such thing as a free ride when generating power (some effort is always required), but higher efficiency means more of your pedalling energy goes toward charging your devices.

Testing shows the PedalCell achieves an impressive 68% efficiency, outperforming the best dynamo hubs. The Velogical rim dynamo comes in slightly ahead of a lower-performing hub at around 35% efficiency. For comparison, top-tier dynamo hubs typically average between 50–60% efficiency during charging, while lower-performing hubs hover around 30–35%.

You can read my full hub dynamo efficiency analysis HERE.

Note: These efficiency figures come from a different test setup and protocol, and the hub dynamos were tested under lower power draw conditions. So, please consider these numbers as rough benchmarks rather than exact comparisons.

I’ve calculated the following numbers based on the dynamo drag at the wheel vs. how much output power is offered at the USB port:

PedalCell Rim Dynamo USB Charger
71% @ 10 km/h
71% @ 15 km/h
66% @ 20 km/h
68% @ 25 km/h
68% average efficiency between 15-25 km/h

Velogical Rim Dynamo with Forumslader USB Charger
7% @ 10 km/h
29% @ 15 km/h
37% @ 20 km/h
41% @ 25 km/h
36% average efficiency between 15-25 km/h

Velogical Rim Dynamo with Velogical USB Charger
21% @ 10 km/h
31% @ 15 km/h
35% @ 20 km/h
39% @ 25 km/h
35% average efficiency between 15-25 km/h

Charging A Battery Pack With The PedalCell

If you’re touring at 15 km/h, the PedalCell outputs 5 volts at 1.04 amps, which translates to 1040 mAh of charge per hour of riding. Charging a 5000 mAh battery pack from empty would therefore take about 4 hours and 48 minutes.

However, charging circuits typically experience small losses, usually between 10% and 30% of the generated power. Accounting for an average 20% loss, the actual ride time needed to fully charge the battery increases to around 5 hours and 45 minutes.

At 20 km/h, the PedalCell delivers 5 volts at 1.46 amps, providing 1,460 mAh per hour. Under these conditions, factoring in similar charging losses, it would take approximately 4 hours and 6 minutes to fully recharge the same 5000 mAh battery pack.

High Power Output = High Drag

While the PedalCell and other rim dynamos offer impressive efficiency, they do come with higher drag, mainly because of the large amounts of power they can produce.

That said, the increased drag only occurs when your connected device is drawing significant power.

For high-speed riding, I recommend charging smaller devices that require less than 5 watts. The PedalCell even features a dedicated “safety” USB-C port limited to 3 watts, making it an ideal choice for minimising drag at higher speeds.

Velogical vs. PedalCell Rim Dynamo

Velogical

The Velogical Special is extremely compact, elegant, lightweight, and compatible with dynamo lights. Both the Velogical and Forumslader USB chargers include buffer batteries to handle start-stop riding, and the Forumslader charger can be neatly integrated into your steerer tube. Since Velogical dynamos have been on the market for years, they’re generally considered reliable.

While the PedalCell delivers 2.5 watts at just 9 km/h, the Velogical kit requires you to maintain about 12 km/h to reach that same output, so if you’re averaging above 15 km/h, the Velogical system will serve you well for charging on the go.

PedalCell

The PedalCell was only launched in 2020, so its long-term durability, waterproofing, and reliability remain uncertain*.

I recently spoke with the team behind PedalCell, who told me the production model is even more powerful, fully water-sealed, and more compact than the prototype tested by FahrradZukunft. The production unit is now expected to exceed 70% efficiency, which is truly impressive.

If you, like me, typically ride at speeds between 8 and 20 km/h, the PedalCell is a compelling option. It delivers low drag and high power output at these speeds—performance unmatched by any hub dynamo setup at low speeds.

Keep in mind, however, that the PedalCell system doesn’t include a buffer battery. If you’re riding uphill (below 8 km/h) or tackling routes with frequent stops (like long traffic lights), you’ll want to add one to maintain steady power.

*Update: Some users have reported failures in 2022, and this video highlights issues like magnets not being properly glued, so it’s worth doing your research before buying.

Rim Dynamo Summary

At first, I was quite surprised by these results.

But the more I considered it, the more it made sense that a rim dynamo could deliver such high power and efficiency. The PedalCell system, in particular, is finely tuned from the rim dynamo right through to the charging electronics—everything is designed to work seamlessly together.

By contrast, hub dynamos and chargers must accommodate hundreds of different lights and USB chargers, which inevitably leads to compromises. Plus, hub dynamo designs are often constrained by German legal regulations (StVZO) on power output, limiting their full technological potential.

Over the past decade, dynamo charging setups have made incredible progress, and I’m excited to see how these rim dynamos evolve in the coming years. Judging by these test results, the future looks very promising for this technology.

Learn About Dynamo USB Chargers HERE, Dynamo Hubs HERE, Dynamo Wiring Systems HERE, Pass-Through Batteries HERE and Dynamo Lights HERE

The post Rim Dynamos Can Now Generate 70% MORE Power Than Hub Dynamos appeared first on CYCLINGABOUT.com.

This comprehensive new testing paired four dynamo hubs with different lights and USB chargers, taking measurements at speeds between 0 and 30KPH. Based on the findings, I’m very surprised to discover how different a simple 6-volt, 3-watt dynamo hub can perform.

This is going to be a technical article but stick with it if you can. The results reveal some very important information about how to best pair dynamo hubs with different dynamo lights and USB chargers.

The Dynamo Hubs On Test

The Schmidt SON28 (pic 1) hubs have always been the industry standard in terms of both efficiency and reliability. These German-made hubs are also the most expensive (US $280+); so does the performance of the hub match the price?

Shimano, who are the largest dynamo hub manufacturer in the world, recently released the Shimano DH-UR700 (2nd pic) and they’re claiming it has 44% less drag than the previous generations (no speed or resistance specified). Thanks to a new alloy axle, it weighs just 477 grams which makes it the lightest hub dynamo Shimano has ever made.

The Shimano DH-3D32 (pic 3) is an older and more cost-effective dynamo hub – in fact, you can have almost three of these hubs for the price of a SON28! The downside is that it’s 685 grams, which is almost twice as much as as the lightest hub in the test. Let’s see if it can make up for its hefty weight with a stellar performance.

The Shutter Precision PD-8 (pic 4) has grown in popularity in recent years thanks to its modest cost (US $130) and ultra light weight (it’s just 410 grams).

You can learn everything I know about dynamo hubs HERE.

The Dynamo Lights On Test

The kLite Bikepacker Ultra (pic 1) is the brightest dynamo light on the market, putting out a whopping 1300 lumens at 25km/h. There are two beam patterns available, a narrow and long beam for the road, and a short and wide beam for off-road. This handmade unit isn’t cheap (US $220), but it’s a very well-proven product in the ultra-racing world.

The Busch & Muller IQ-X is one of the brightest lights available for the road (100lux), with a near-perfect beam shape for everything but singletrack (in my opinion). It also meets the StVZO regulations in Europe so you can legally use them around the streets (basically, the light doesn’t shine oncoming people in the eyes). At US $163, it’s pricy – but hey, it has the brightest legal beam available.

The Supernova E3 PURE 3 is a beautiful German-made light. At 205 lumens it’s not the brightest, but it’s waterproof (it will literally run submerged underwater), ultra-light (90g!), has a StVZO beam and has a five-year warranty. This model doesn’t come with an on/off switch, but the E3 PRO 2 does (this is what I recommend on Amazon US $183).

The Spanninga Nomad is an ultra-cheap city light with about 40lux of light (that’s 40% the light of the IQ-X). The beam is not particularly long or bright, so it’ll be best for slower riding speeds in illuminated areas.

You can read everything about the best dynamo lights for bicycle travel HERE.

The Dynamo USB Chargers On Test

The kLite USB (pic 1) has been developed specifically for the backcountry. While not the most powerful charger available, the emphasis of this unit is on reliability. As a result, the kLite is as simple as possible, using thick internal cabling, full waterproofing and smoothing capacitors that offer ultra-consistent waveforms to your device.

The Igaro D1 (pic 2) is a discontinued dynamo USB charger from Igaro in the UK. It features a very compact size, titanium body and IP69 waterproofing – all in an ultralight package.

One of the original USB chargers is the B&M USB Werk (pic 3). It has a built-in cache battery which, for a short time, can add power to your device when going up hills or stopping at traffic lights.

The Spanninga Nomad (pic 4) is the same dynamo light as above, but the cool thing is it also has a USB charger built-in! Let’s find out if an ultra-cheap, integrated unit like this can also offer a decent charge.

You can read my detailed resource covering the best dynamo USB chargers HERE.

The Lab Test

The Skjegg test rig is essentially a fork and dynamo front wheel, which has been clamped onto a heavy steel plate. Replacing the disc rotor is a cog which connects via a chain to an electric motor mounted on the steel plate. The electric motor is then connected to a laboratory DC power source, where you can control the voltage, and therefore, wheel speed. Speed ​​is monitored by a bike computer and the voltage is measured with a multimeter. Multiplying the readings of the devices, you can calculate the power that the engine needs to consume to spin the dynamo to the required speed. The power of headlights and USB chargers was measured to an accuracy of 0.1 W and the speed to an accuracy of 0.1KPH.

The hub drag is measured indirectly at the electric motor, rather than at the dynamo hub. To determine the dynamo hub drag, Skjegg had to first find all of the drag losses in his test rig. He used a standard bike hub to determine a baseline system drag which could then be subtracted from the drag results of the dynamo hubs (at varying speeds, with different lights and chargers connected). With the influence of slight variations in chain tension between hub tests, the drag has been measured to an accuracy of 1-watt.

It’s worth noting that this test was conducted with quick-release hubs only. Thru-axle and fat bike dynamo hubs might yield different results due to the varying magnet systems.

If you would like to read more about how Skjegg conducted their test, please go to part three of their original article HERE.

Results: Drag Difference Between Lights & Resistors

The FahrradZukunft dynamo test that I previously analysed connected an electrical load resistor (rather than a dynamo light/charger) to different dynamo hubs to find the drag. This is an ok way to benchmark different hubs against each other, but according to Skjegg, it doesn’t accurately measure the drag.

Skjegg show in the graph above how a dynamo light and resistor can consume virtually the same amount of power but have a significantly different drag. Importantly, the drag numbers you see below have been extracted from actual dynamo lights and USB chargers – not resistors.

Results: Maximum Power Point Tracking (MPPT)

Another interesting thing that Skjegg revealed was the maximum power available at different speeds from a Shimano UR700 dynamo hub. Actually, dynamo hubs will put out more power than this but this is the maximum power with the minimum drag.

Using a rheostat, the resistance was manually adjusted until the maximum power output was found at different speeds. As you can see in the graph there is a relatively large difference between the Igaro D1 USB charger output power and the MPPT of the Shimano UR700 hub (it’s often 50% more power).

MPPT of a UR700 Hub vs. Best Dynamo USB Charger Currently Available
5KPH – 1.5W (MPPT) and 0.25W (Forumslader V5)
10KPH – 2.6W (MPPT) and 1.7W (Cinq Plug5 Plus)
15KPH – 4.2W (MPPT) and 3.5W (Cinq Plug5 Plus)
20KPH – 6.0W (MPPT) and 4.8W (Forumslader V5)
25KPH – 7.7W (MPPT) and 6.5W (Forumslader V5)
30KPH – 9.1W (MPPT) and 7.4W (Forumslader V5)

Currently, the biggest areas of improvement in charging look to be found between 5-10KPH where we are only extracting 17-65% of the maximum power available from the hub. After 15KPH, we are already able to charge at 80%+ of the maximum power.

Results: Maximum Power Point Tracking (MPPT) vs. Drag

Skjegg also found the MPPT of the other three dynamo hubs. As you can see, the Shimano hubs (new and old) offer the most output power, followed by the Schmidt SON28 and SP PD-8.

He then graphed the MPPT alongside the hub drag. Shimano’s new UR700 hub can technically offer less drag than the older 3D32 despite developing more potential power – a nice update. The Schmidt SON28 offers the smallest difference between output power and drag, indicating it is the most efficient. And the SP PD-8 is the least powerful hub with a somewhat high drag, especially at speeds above 20KPH.

Results: Dynamo Hub Drag (Electronics Off)

Light/USB Switched OFF While Cycling @ 10-30km/h
Schmidt SON28 // 1.40w-1.90w drag
SP Dynamo // 1.90w-5.20w drag
Shimano UR700 // 1.40w-4.50w drag
Shimano 3D32 // 1.90w-4.30w drag

This test determines how much extra resistance your dynamo hub creates when there is nothing connected.

The drag between 5-10km/h is within 0.5-watts for all dynamo hubs, but when we hit 15km/h the differences become much more pronounced, with the highest-performing hub (SON28) running 1.1-watts less resistance than the lowest-performing (SP). The difference in drag continues to increase as the speeds get higher; the biggest difference is at 30km/h where the SON has 3.3-watts less resistance than the SP, and 2.5-watts less resistance than the Shimano hubs.

Results: Dynamo Hub Drag and Output Power Using Different Lights

Key Talking Points for the kLite Bikepacker Ultra:
– The Shimano UR700 hub provides the most light from 5KPH to 17.5KPH, with a maximum brightness at 20KPH (6-watts).
– The SON28/3D32 hubs offer the most light from 17.5KPH to 22KPH, with a maximum brightness at 20KPH (7-watts).
– The SP PD-8 hub offers the most light after 22KPH.
– Compared to the SON28, the SP offers 35% more power to the light at 25KPH.
– The drag is lowest for the SON28 at maximum power (18-watts), but not by much.
– At low speeds, the drag is considerably higher with the UR700 hub (but you get 10-25% more light).
– The drag is 24.5-watts(!) with the SP at maximum power; if you want a bright-as-hell light, you’ve gotta pedal hard for it.
– Average lighting efficiency between 10-30KPH: SON28 (42.6%), 3D32 (38.2%), PD-8 (32.7%), UR700 (31.3%).

Key Talking Points for the B&M IQ-X:
– The UR700 again provides the most light up until 12.5KPH, but it has considerably more drag too (14.5W @ 15KPH!).
– The 3D32 hub offers exceptional power at 15KPH and relatively low drag at higher speeds too.
– The SP provides the least light until 18KPH, but the most light above 20KPH.
– The SON28 offers 3 to 4-watts less drag than the SP or UR700 hubs at speeds above 20KPH.
– The drag numbers for the SP are quite high compared to the SON28 considering it’s only providing 10% more light.
– Average lighting efficiency between 10-30KPH: SON28 (42.1%), 3D32 (39.2%), PD-8 (34.0%), UR700 (30.8%).

Key Talking Points for the Supernova E3 Pure 3:
– This light is clearly optimised for speeds above 25KPH as it has pretty low power outputs at slow speeds.
– The good news is that the drag is low at slow speeds as a result of the low power outputs.
– The UR700 extracts the most out of the light at all speeds.
– At 25 to 30KPH, the SON28 or 3D32 are the best options when considering both the brightness and drag.
– Average lighting efficiency between 10-30KPH: SON28 (43.6%), 3D32 (39.7%), UR700 (33.0%), PD-8 (32.2%).

Key Talking Points for the Spanninga Nomad:
– The output power is very low, only 40% of the B&M IQ-X.
– The output power is obviously optimised for city riding, with maximum power available at 10KPH on my hubs.
– For the same brightness, the SON28 has 30-50% less drag than other dynamo hubs.
– Average lighting efficiency between 10-30KPH: SON28 (45.9%), 3D32 (31.5%), PD-8 (26.7%), UR700 (24.4%).

Results: Dynamo Hub Drag and Output Power Using Different USB Chargers

Key Talking Points of the kLite USB Charger:
– The Shimano UR700 is a great option at lower speeds, offering 1-2 watts more power than the SON28.
– The SP PD-8 requires a high average speed (18KPH) to meet the minimum charging specification for a smartphone (2.5W).
– The Shimano hubs are the only option with the kLite that can charge batteries at under 10KPH (kLite claim down to 8KPH).
– The SON28 drag is significantly lower than the SP, yet offers more power.
– Average charging efficiency between 15-30KPH: SON28 (60.2%), 3D32 (44.5%), UR700 (39.8%), PD-8 (31.9%).

Key Talking Points of the Igaro D1:
– The power and drag curves are little unusual on all but the SP PD-8 hub.
– The D1 offers exceptional charging efficiency with the SON28 at 20KPH in particular (84%!).
– The charger requires a minimum of 13KPH (UR700) to 17KPH (SP) before it will hit smartphone charging specification (2.5W).
– The Shimano UR700 can provide 2-3W extra power at 30KPH (with a lot of extra drag).
– Average charging efficiency between 15-30KPH: SON28 (59.9%), 3D32 (43.9%), UR700 (40.5%), PD-8 (33.5%).

Key Talking Points of the B&M USB Werk:
– The USB Werk requires 13KPH (3D32) to 17.5KPH (SP) to hit the smartphone charging specification (2.5W).
– Maximum power output at 30KPH varies very little, but the drag is 40% lower on a SON28 hub.
– The USB Werk looks to have been optimised for the SON28 as it offers moderate power with the lowest drag.
– Average charging efficiency between 15-30KPH: SON28 (48.5%), 3D32 (39.3%), PD-8 (31.7%).

Key Talking Points of the Spanninga Nomad Charger:
– The charger will not be very useful until 17 to 21KPH when it can hit the smartphone charging specification (2.5W).
– At speeds between 20 and 30KPH it is actually a very solid little charger, offering more power than most.
– When using the UR700 hub the drag is very high in proportion to the power output (the 3D32 would be the better buy).
– Average charging efficiency between 15-30KPH: SON28 (56.9%), 3D32 (43.6%), UR700 (38.6%), PD-8 (34.4%).

Which Dynamo Hub Is The Best?

The Schmidt SON28 is incredibly efficient across the board making it the undisputable king of dynamo hubs. Despite it usually running the least amount of drag, it offers the 2nd or 3rd-most power in all cases (with ~57% efficiency on charging). Not only that, but SON28 hubs are reliable and use high-grade SKF sealed bearings to help them run smoothly for more than 50,000km. These hubs are super expensive but, in my opinion, are quite good value when you consider the performance on offer.

The Shimano DH-UR700 consistently offers the most power at speeds between 5KPH and 15KPH (3-9MPH), so it’s going to be a great option for off-road or hilly terrain. It’s also often the most powerful hub for charging devices. The only downside is the drag – the hub is powerful but slow. In fact, you’ll often find the drag is 50% less on the SON28.
Shimano UR700 Quick Release – US $152 (Amazon Special HERE)
Shimano UR705 12mm Thru Axle – US $123 (Amazon Special HERE)

The Shimano 3D32 is a $99 dynamo hub that packs amazing performance for the price. When we factor in both the output power and drag, this cheap hub ranks 2nd after the SON28 in almost all cases (~44% charging efficiency). If you are choosing between the Shimano hubs, this would be the one to pick if (a) your average speeds are higher than 18KPH and (b) you don’t mind the extra 200+ grams.
Shimano S501 Quick Release (same internal unit & performance) – US $99 (Amazon Special HERE)

The SP PD-8 offers the most power at high speeds with both the kLite Bikepacker Ultra and B&M IQ-X lights. But otherwise, the results are quite disappointing, especially when paired with a USB charger where it offers the least amount of power of all hubs and poor average efficiency of ~34%. That said, the output power and drag information are just one aspect of a dynamo hub – SP hubs are still great! They work out to be very reliable, ultra-lightweight and affordable, especially the 15mm axle version which is literally half the price of a SON28 ($185 vs $350).
Exposure Revo 15mm Thru Axle (same hub as SP) – US $185 (Amazon Special HERE)

Note: You can support this website by purchasing dynamo hubs through Amazon. I make a small commission on any sales, at no cost to you!

Summary

This data sheds a lot of light (pardon the pun) on the differences between dynamo hubs. I’m quite surprised by these results as I had no idea there was so much performance variation between hubs, in both drag and power output.

Until now, the differences between dynamo hubs have been a bit of a mystery. This is because almost all lab tests have used Schmidt SON28 hubs for power generation. In addition, previous dynamo light tests have used electrical load resistors to simulate the output power rather than actual lights. As Skjegg Blogspot have shown, there is a marked difference in hub drag when we connect a dynamo light.

The amount of drag in Shimano and SP dynamo hubs is higher than I understood it to be. Previously I have stated that dynamo hubs have a charging efficiency of between 50-60%, but this new data shows that only the Schmidt SON28 can claim that with a 57% charging efficiency. Comparatively, the Shimano hubs run between 39-44% efficiency while the SP hub works out to be 34% efficient.

Assuming you’re generating 4-watts of USB power from your dynamo hub when you use an SP PD-8 over a Schmidt SON28, you can expect more than 5-watts of extra hub drag – that’s a lot! I’ll have to write a more detailed article on how drag affects your speed soon.

The post NEW Dynamo Hub Power and Drag Testing: Schmidt SON vs Shutter Precision vs Shimano appeared first on CYCLINGABOUT.com.

These special batteries provide continuous power to your devices during times when your speed is too low for USB charging, for example, when cycling on hilly terrain, or when stopped at traffic lights. This prevents your devices from receiving then losing charge (eg. smartphones) or switching themselves off entirely (Garmin eTrex models).

We’ll be taking a closer look at buffer batteries, battery storage, charging times and some dynamo chargers with in-built batteries in this article.

Pass-Through Batteries

Most batteries will either charge OR send their stored power to your device; rarely will they do both simultaneously.

Pass-through batteries are able to deliver power from your hub straight to your device, while also taking a charge if there’s any power leftover.

The reason many battery manufacturers don’t allow pass-through is that it can deteriorate batteries quickly, although you can still expect a minimum of 500 total charge/discharge cycles with most pass-through batteries (two half charges equate to one full cycle).

It’s worth noting that many manufacturers include “pass-through” as a feature on the battery spec sheet, but in my experience, this is rarely the case.

Battery Storage Losses

When power is stored in a battery, it experiences a storage loss of 15-20%. In order to minimise this loss, it is best to try to charge your electronics either straight from the USB charger or by using a pass-through battery. It’s nice to have that power on tap, but when it means you lose 1-hour of power per 5-hour ride… it adds up.

Lipstick Buffer Batteries

Batteries are getting smarter circuitry in order to reduce long-term deterioration. But not all batteries are smart!

Jesse Carlsson and Sarah Hammond use the cheapest lipstick batteries they can find to keep a constant stream of power running to their Garmin eTrex GPS units. It’s not guaranteed that the cheapest batteries will be ‘dumb’ enough to allow pass-through, but the odds are good and given they’re less than $10 – it’s worth giving them a go.

Check out Jesse and Sarah’s video on how to waterproof these cheap buffer batteries in their video HERE.

Variable Current Buffer Batteries

If lipstick batteries are dumb, variable current buffer batteries are smart!

A current limiting buffer battery is designed for dynamo hub charging, allowing you to switch between set charging currents (eg. 100, 400 or 900mA) for different riding speeds.

The main advantage is that you can optimise your charging current so that your battery can draw a charge at really low speeds (eg. 6-8km/h). This kind of feature is also handy for charging with solar panels in low-light conditions.

If you’re riding at higher speeds, however, these batteries are less useful because they limit your charging potential to 4.5-watts (many modern dynamo chargers will charge at between 5 and 7-watts once you hit 20kph).

You can see the power graphs for different dynamo USB chargers HERE.

Soshine E4S Battery Kit

This buffer battery kit has been recommended by Velogical, who make rim dynamo charging systems.

The E4S requires 2x 18650 Li-ion batteries (sold separately) to complete the kit. Velogical recommends Samsung INR 18650-29E batteries.

Make sure to pre-charge the buffer batteries using a regular USB charger with a type-B plug.

How Long Will A Battery Take To Charge?

To understand this section well, you may need to learn about volts, amps and watts HERE.

A 3-watt dynamo hub will put out an average of around 6-volts at 500mA. Once the power has been converted from AC to DC the output will translate to roughly 5V and 500mA (or 2.5 watts), which for an hour of riding is 500mAh. Charging a 3000mAh battery from scratch will, therefore, equate to 6 hours of riding at 12km/h with the most powerful USB chargers, and 20km/h with other USB chargers.

However, there are also small losses in the charging circuitry, perhaps around 20% of the total generated power. Adding the 20% extra ride time (6 hours + (6 hours x 0.2)) and we’re looking at 7.2 hours of riding to fill the battery from scratch.

You can also use the above assumptions when determining how long it will take to fill a phone battery. My Apple iPhone SE has a ~1500mAh battery, so at 500mA per hour, it should take 3 hours. Adding in the circuitry losses and I’m looking at 3.6 hours of riding to fill it up. Other modern smartphones like the Samsung S8 will have 3000mAh batteries, resulting in 7 hour + charge times.

Having said all that, there are products which use special capacitors to achieve twice the power, charging smartphones in literally half the time. Many of them also come with build-in buffer batteries. Check out the Cinq Plug5 Plus and Forumslader V5 USB chargers which will achieve 4-5 watts power at just 17-20km/h.

Charging Regular Batteries

You can, of course, charge batteries without pass-through too!

Large capacity batteries (5000mAh+) are great for storing power but can sometimes be problematic to charge as they have more internal resistance in the battery cells. In order to overcome the resistance, bigger batteries require a higher input current (eg. 1A) which is easy for a wall outlet but harder for a dynamo hub at touring speeds. This is why many 5000mAh+ batteries don’t charge particularly well from dynamo hubs.

That said, if you’re cycling at speeds over 25km/h, or you use one of the powerful USB chargers, you can sometimes charge batteries up to 10000mAh – but I’d still recommend 2x 5000mAh batteries instead.

Dynamo Hub Chargers With In-Built Pass-Through Batteries

As dynamo hub charging technology matures, we’re finding manufacturers fitting buffer batteries straight into their chargers. This simplifies the cabling, in particular, making for very neat charging solutions!

You can find integrated buffer batteries in the:
Cinq Plug5 Plus (1100mAh)
Forumslader Ahead (2100mAh)
NC-17 Appcon 3000 (3000mAh)
Lumi-Con P5 (5000mAh)
Busch & Muller USB Werk (300mAh)
ZZing (2000 or 2700mAh)

My full list of dynamo chargers is HERE.

Buffer Battery Recommendations

Soshine E4S 18650 x2 Kit / 5700mAh
Cinq Smart Power Pack II / 3000mAh / 85g – €99 on Cinq
Lipstick Battery (I haven’t tested this battery, but it should do the trick) / 2600mAh / $9.99 on Amazon

Igaro also keeps a list of batteries with pass-through (click the link for the latest):
Blitzwolf – BW-P3, BW-P5 (probably other models in this range)
Miller – ML202 V4
RavPower – Turbo+ RP-PB043
Thrunite – C2
Tomo – M2, M4 (probably other models in this range)
Blackweb – 20,000mAh (Walmart, Adsa)

Check Out Some Of My Other Resources On Dynamo Systems, Dynamo Lights and USB Chargers

The post All About Buffer Batteries With Pass-Through Charging For Dynamo Hub Systems appeared first on CYCLINGABOUT.com.

Dynamo USB charger technology is actually improving at an incredibly fast rate. Very small companies (ie. often just one person) are designing both hardware and software that exploits the very modest power offered by a dynamo hub. The result is powerful USB chargers that offer high levels of efficiency, that can be neatly fitted to any bike.

This is a pretty technical resource, so strap yourselves in and take it slow. A big focus will be the power output of different chargers at different speeds, but we’ll also look at dynamo hub drag, charger efficiency, form factor and how quickly you can expect your batteries to charge.

This article was originally written September 2017 but has been re-written in July 2019 with the latest information.

Watts, Volts and Amps

Firstly, let’s quickly cover a few basic electricity units of measurement. It’ll take a moment to get your head around this, but the knowledge will help, promise!

Today we’ll be discussing voltage (in volts or ‘V’) and current (in amps, or ‘A’). A common analogy for these units of measurement is in terms of a water pipe. Voltage is the water pressure and current is the flow rate. By increasing the water pressure in a pipe, you will increase the flow rate too. It’s the same with electrical systems; increasing the voltage increases the current.

Watts (W) is the total electrical system power, equal to the voltage (V) multiplied by the current (A). The equation is, therefore:
Watts (W) = Volts (V) x Amps (A).

A 3-watt dynamo hub will put out 6 volts at 0.5 amps (3W = 6V x 0.5A) in AC power. Once the power is converted to DC it’s more like 5V and 0.5A, which is the power required for USB charging. While some USB chargers will start charging at lower rates of power, most devices like to charge above 2-watts (5V x 0.4A) to ensure the charging level is stable.

2-watts can be reached by the best dynamo USB chargers at speeds between 11-13kph. If you’re cycling at lower speeds for short periods of time, a buffer battery will need to be incorporated into your charging system to help meet the power needs of your device. And when cycling for long periods of time below 11-13kph, you’ll need to look to other charging solutions (solar or power banks are usually best for off-road bikepacking).

Most dynamo USB chargers use chipsets with a current limit to prevent overheating (eg. Sinewave Revolution is 1A, therefore the maximum power is about 5W (5V x 1A)). It can be said that any USB charger that puts out high watts will also be putting out a high current.

The Most Powerful Dynamo USB Chargers

Fahrrad Zukunft has conducted some very extensive testing over the years that determines the amount of power (in watts) that can be produced by various dynamo USB chargers. The three below charts (2016, 2016 and 2019) compare 13 different models.

To put the below numbers in perspective, consider that a smartphone consumes around 3-4 watts in navigation mode with full-screen brightness. Therefore, just to keep the battery at the same level will require cycling speeds of 15 to 25kph depending on the model of USB charger. Even then, there’s only a handful of products that generate enough power for this activity.

Let’s take a look at the numbers.

The graphs above show the output power at the USB port at various cycling speeds. You’ll notice that most power curves are rather linear from 5kph until they plateau somewhere between 20-40kph. The exception is the Forumslader V5, which uses a special series of capacitors to boost the power potential of a dynamo hub at low speeds.

Power at different speeds:
1 Watt – Most chargers will hit 1w between 7-10kph.
2 Watts – At 11kph the highest performing charger hits 2w (Plug5 Plus). Most other chargers will hit 2w between 12-15kph
3 Watts – At 14kph the highest performing charger hits 3w (Plug5 Plus). Other chargers hit 3w between 15-25kph
4 Watts – At 17kph the highest performing charger hits 4w (Plug5 Plus) – Other chargers hit 4w between 27-28kph
5 Watts – At 20kph the highest performing charger hits 5w (Forumslader) – Some chargers hit 5w above 35kph

The top-performing chargers:
Cinq Plug5 Plus – 2w@11kph, 3.5w@15kph, 4.5w@20kph, 5w@25kph – Best for sub-20kph speeds
Forumslader V5 – 2w@12kph, 3w@15kph, 4.75w@20kph, 6.5w@25kph – Best for above-20kph speeds
Lumi-Con P5 – 2w@12kph, 3w@15kph, 4w@20kph, 4.25w@25kph
Dynamo Harvester Plus – 2w@14kph, 2.5w@15kph, 4.5w@20kph, 6.25w@25kph

Igaro has recently published some non-independent results for a few missing chargers. These numbers don’t perfectly align with Fahrrad Zukunft, but they are within 10% when examining the Sinewave Revolution. The x-axis is measured in amps, but we can use the equation to convert amps to watts by multiplying by 5 (volts).

Here are some quick conversions:
10kph – Igaro D2 (1.1w), E-Werk (0.9w), Sinewave (0.9w)
15kph – Igaro D2 (2.5w), Igaro D1 (2w), kLite (1.75w), Sinewave (1.75w), E-Werk (1.75w)
20kph – Igaro D2 (4w), Igaro D1 (3w), kLite (2.75w), Sinewave (2.75w), E-Werk (2.75w)
25kph – Igaro D2 (5.2w), Igaro D1 (3.75w), kLite (3.5w), Sinewave (3.5w), E-Werk (3.5w)
30kph – Igaro D2 (6w), Igaro D1 (4.75w), kLite (4.5w), Sinewave (4.5w), E-Werk (3.5w)

Dynamo Hub Drag

There is no such thing as free energy! Do you want a powerful charging system? Ok, well you’re going to have to pedal a bit harder for it. Let’s take a look at dynamo hub ‘drag’ from using different charging systems.

The charts above show the power created at the dynamo hub by different USB chargers. The efficiency of a high-quality dynamo hub at low power (eg. cycling at 10-20kph) works out to be around 50-60%. This means that when the charger is making between 1-3 watts you can roughly double that figure to work out the drag (in watts) at the hub.

Therefore, when making 2.5 watts for USB charging, you’re using about 5 watts of your pedalling power. That drag equates to ~0.4kph slower riding speeds than if you weren’t charging (80kg rider / 15kg bike and gear / 150 watts / flat road). Or a ~3-minute time penalty over a 100km ride.

The efficiency increases to 70-80% at high power (ie. cycling at 30kph). This means that a charger like the Forumslader V5 will be taking 15-watts from your pedalling power while charging at 10.5 watts. That drag equates to ~1.1kph slower riding speeds than if you weren’t charging at 10.5 watts (80kg rider / 15kg bike and gear / 150 watts / flat road). Or a ~9-minute time penalty over a 100km ride.

That’s a decent chunk of time, so it’s in the best interests of charger manufacturers to make efficient units that don’t create too much power, or the drag becomes particularly noticeable when riding.

Power Banks & Charging Batteries

Once you drop below around 2-watts, a dynamo charger will not be able to provide power to most devices. But luckily, some chargers have integrated buffer batteries that will swoop in and provide the power needed for low-speed riding. For this feature, check out the Cinq Plug5 Plus, NC-17 Appcon 3000, Lumicon P5, Forumslader V5 and B&M USB-Werk.

Charging Batteries or Power Banks
If your speed is regularly dropping above and below 11-13kph, it’s best to charge into a power bank for later use. But this is not the most efficient way to keep your devices charged because there are energy losses in the additional circuitry. When power is stored in a battery, it experiences a storage loss of around 15-20%. This means you lose around 1-hour of power generation per 5-hour ride, which adds up!

If you’re cycling faster than 11-13kph, make sure to minimise this loss in efficiency by charging your electronics either straight from the USB charger or by using batteries with a ‘pass-through’ feature (the Cinq Smart Power Pack is the best available).

How Long Does It Take To Charge A Battery?
This depends on the dynamo USB charger and your cycling speed. Let’s take a look at two different power outputs.

Example One: 2.5-Watts (12.5kph on the Cinq Plug5 Plus)
Once a 3-watt dynamo hub has been converted from AC to DC the output will translate to roughly 5V and 0.5A, which for an hour of riding is 500mAh. Charging a 5000mAh battery will, therefore, equate to 10 hours of riding. However, when we factor in the small losses in the charging circuitry, we lose around 20% of the total generated power. Adding the 20% extra ride time (10 hours + (10 hours x 0.2)) and we’re looking at 12 hours of riding to fill the battery from scratch.

Example Two: 4-Watts (17kph on the Cinq Plug5 Plus)
If we use fancy circuitry to boost the output power to 4-watts (5V and 0.8A), we can fill a 5000mAh battery in 6.25 hours of riding. When we account for the ~20% losses in the charging circuitry, this results in 7.5 hours of riding to theoretically fill the battery from scratch.

You can usually find out the battery size of your USB device in the product specifications or written on the battery itself. Read more about power banks and buffer batteries in my resource HERE.

20-Minute Charging Test

While the graphs above give us an idea of the power output at specific speeds, in the hills, it is unusual to cycle at a constant speed for long periods of time. To help simulate hilly or undulating riding conditions, Fahrrad Zukunft created a dynamic test with varied cycling speeds to see which dynamo USB chargers could generate the most power. The test is probably a little over the top in speed variation, but it’s still pretty interesting to see the losses in the charging circuitry.

The test changed the cycling speed in 2-second steps from 10kph up to 30kph and then back down to 10kph again. The accelerations between steps took 3-seconds. This 20-minute test essentially exposes the responsiveness of the microcontrollers inside the chargers, which are constantly trying to optimise the output power at different cycling speeds.

Output power at the USB port after 20 minutes:
1. Forumslader V5 (1200mWh or 240mAh)
2. Lumi Con P5 (1000mWh or 200mAh)
3. Plug5 Plus (1000mWh or 200mAh)
4. NC-17 Appcon 3000 (900mWh or 180mAh)
5. USB Werk (600mWh or 120mAh)
6. Zjego (400mWh or 80mAh)

The test also shows differences in charging efficiency. The bigger the difference between the mWa at the dynamo hub and USB port, the more inefficient the charging system. For example, the Zjego turns 1000mWa into only 400mWa in this test, indicating some very big losses in the circuitry (~40% of power retained). On the other hand, the Forumslader V5 retained ~66% of the power created.

Tying this back to battery charging in the previous section, we could expect the Forumslader V5 to charge a 5000mAh battery in 8.33 hours (including losses in the battery circuitry). The Plug5 Plus would take 10 hours. The USB-Werk would take 16.65 hours.

The Neatest Dynamo USB Charging Systems

Steerer Tube USB Chargers
I don’t know about you, but I really appreciate a neat and integrated charging solution – and the steerer tube mounted systems have got to be the best in this regard. I personally use the Plug5 Plus which integrates a 1100mAh buffer battery inside the steerer for cycling at speeds below 11kph. A very neat metal ring seals the USB-C port from the elements when needed.

Check out the Cinq Plug5 Plus, Forumslader V5 Aheadring, Sinewave Reactor and Cycle2Charge V2.

Regular USB Chargers
Ortlieb has a handlebar bag called the Ultimate 6 Pro E which has connectors built into handlebar bag mount. This allows you to keep your USB charger and devices inside your waterproof bag, and take the handlebar bag off without unplugging anything. That just leaves a few wires on your bike – a very neat solution!

Dynamo Light USB Chargers
Here’s another super neat charger design. There are a handful of lights that also incorporate the circuitry for charging USB devices. This creates a very neat (less cabling) and often cost-effective light+charger. That said, some light/chargers are less efficient than standalone units because they are not optimised around charging.

Check out the Sinewave Beacon, Forumslader IQ-X, Axa Luxx70 Plus and B&M Lumotec IQ2 Luxos.

Testing Your USB Charger

If you’re having issues with charging, a cheap USB LCD Voltmeter can help diagnose whether your USB charger is making the right amount of power. If you’ve determined you’re getting the right voltage and current for your device, you may be having issues with the particular cache battery you’re using.

The Best-Performing Dynamo USB Chargers

Cinq Plug5 Plus // Sub-20kph
Most bike travel is conducted at speeds below 20kph (12mph), and the charger that offers the most power at these speeds is the Plug5. Not only is it powerful, but it also integrates a buffer battery into the system for the times you’re cycling below 11kph. The covered USB port is very neat too!

Cinq Plug5 Plus Numbers:
2w @ 11kph
3.5w @ 15kph
4.5w @ 20kph
5w @ 25kph

Forumslader V5 // Above-20kph
The Forumslader V5 uses a special series of capacitors to achieve big power from 20 to 30kph (12-19mph) in particular. It also incorporates buffer batteries (3x700mAh) and a neat USB port near the handlebars.

Forumslader V5 Numbers:
2w @ 12kph
3w @ 15kph
4.75w @ 20kph
6.5w @ 25kph

Creating Bombproof Dynamo USB Chargers

Kerry from kLite focuses on building dynamo light and charging systems for remote backcountry use. His main aim is reliability, so his charging systems are as simple as possible, using thick internal cabling, full waterproofing and smoothing capacitors that offer ultra-consistent waveforms (best practice for direct charging; Kerry says they take up half of his charger).

Usually, more complex circuitry and small form factors result in more chance of something going wrong, so it’s always best to hunt around for reviews online to see how different USB chargers are performing in the world’s harshest environments.

List Of Different Dynamo USB Chargers

You can see a list of most hub dynamo USB chargers options HERE.

Summary

The top-tier dynamo USB chargers offer very decent power these days, provided your touring speed is above 11-13kph. Once you hit 15kph with five of the charging units tested, you’ll be generating more than 3-watts which is a very decent charge for most batteries and devices. And by 17-20kph you can generate 4-watts for even the most power-intensive smartphones.

You can neatly integrate a USB charger into your steerer tube, front dynamo light or handlebar bag via the Ortlieb Ultimate 6E connectors. There are lots of great options!

Remember that you increase the dynamo hub drag when generating additional power, but this will be necessary if you’re a heavy electronics user (eg. smartphone navigation with the screen always on). That said, if you just want to keep on top of your phone or GPS, almost all USB chargers will do this job just fine.

Learn About Dynamo Hub Systems HERE, About Buffer Batteries HERE and Dynamo Lights HERE

The post All About The Best Dynamo USB Chargers For Bicycle Touring and Bikepacking appeared first on CYCLINGABOUT.com.

There are only a handful of dynamo hubs on the market, but there are some significant differences between them. This article will delve into everything you should know about dynamo hubs.

Dynamo Hub Types

Axle Sizes

The most common size for a touring bike is still 9mm quick release, but with axle standards changing both on-road and off-road, we’re now finding touring and bikepacking bikes available with six axle variants.

1. Quick Release 9mm – 100mm
2. Thru Axle Road 12mm – 100mm
3. Thru Axle MTB 15mm – 100mm
4. Thru Axle MTB Boost 15mm – 110mm
5. Fat Bike Quick Release – 135mm
6. Fat Bike Thru-Axle 15mm – 150mm

Connectors

There are two different common forms of spade connector – the Shimano design and the Schmidt SON design. Neither design can be said to be ‘better’ – they both do the same job of transmitting power up the cable. Due to the market split of connector types, dynamo lights and USB chargers tend to come without any connector attached to the cable ends.

A less common connector design is the Schmidt SL fork dropout. This is a really neat design; the connection happens between the edge of the hub and a fork dropout plate that’s soldered to the wiring. Almost every Schmidt hub is made in an SL version. Unfortunately, you’ll rarely find the Schmidt SL dropout on anything but custom-built forks.

Power Specification

There are three different power specifications for dynamo hubs: 1.5-watts, 2.4-watts or 3-watts (all at 6-volts). Given that touring and bikepacking is often conducted at speeds below 25KPH/15MPH, the most powerful option (3W) is necessary for charging USB devices, and it’s the best for low-speed lighting too. That said, 2.4W hubs offer enough power if you’re touring using smaller diameter wheels (16-20″) and 1.5W hubs are appropriate for lighting your way at higher speeds (ie. 25KPH/15MPH).

Spoke Count

Dynamo hubs come with anything from 20 spoke holes for a lightweight carbon wheel builds through to 48 holes for the strongest tandem wheel. Most touring and bikepacking bikes use between 28 and 36 spokes. While spoke count makes some difference, evenly balanced spoke tension across the wheel and a stiff touring rim tend to matter most in terms of strength.

Performance: Dynamo Hub Power Output

At different speeds, dynamo hubs offer varying amounts of power for your lights and USB chargers. The amount of power a dynamo hub delivers will depend mostly on the light or USB charger – but there are also a few tricks dynamo hub manufacturers use to boost their power outputs.

Dynamo hubs paired with powerful USB chargers will provide smartphone levels of charging from about 12KPH (look for 2.5W on the graph). That said, some hub and charger combinations will not deliver 2.5-watts until around 20KPH.

When we compare the power outputs at different speeds for the kLite USB charger (see graph above), you’ll notice the green line of the Shimano UR700 is offering the most power at all speeds, and the red line of the SP PD-8 the least. At 15KPH the UR700 is delivering three times the power output – quite significant considering the hubs both have the same 3W power specification.

That said, if you want high power outputs from your dynamo hub, you have to pay for it with additional drag.

Performance: Dynamo Hub Drag

If you’ve ever picked up a dynamo hub and tried to spin the axle, you’ll know that they feel incredibly ‘notchy’. This is the result of a series of powerful magnets passing a coil and in turn, creating an electric charge. With no light or USB charger connected, this drag only has a small effect on your speed because of the flywheel effect of a rotating wheel. According to the graph above, the drag is between 1 and 5-watts depending on the cycling speed and hub model.

When you connect a light or charger to the hub, the drag will increase. The amount of drag is mostly a function of the light or USB charger that you have connected, but there are variations between hubs too. The graph above shows how four different dynamo hubs perform with the brightest dynamo light currently available, the kLite Bikepacker Ultra. As you can see, the drag increases with the output power and speed. At maximum brightness when using the SP PD-8 hub (25KPH), the drag at the hub is around 24.5-watts, which is likely to be somewhere between 12-20% of your total pedal power. That’s a lot.

You can read the full dynamo hub testing analysis HERE.

Performance: Dynamo Hub Efficiency

A more efficient hub will turn more of your pedal power into power for your lights or charger. We can find out how efficient a dynamo hub is by comparing its power output and drag at different speeds.

The rate of efficiency is quite different for different hubs. For example, at 15KPH a Schmidt SON28 hub provides 1.9-watts to your USB device but will take 3.2-watts of your pedal power (see graph above). That means 59% of the SON28 resistance will be going towards charging your device. In comparison, the SP PD-8 will create 0.9-watts but will take 4.6-watts. In this case, only 20% of the PD-8 resistance will go to charging your device.

Charging Test Averages (Four Different Chargers):
1. SON28 Hub – 57% efficient
2. 3D32 Hub – 44% efficient
3. UR700 Hub – 39% efficient
4. PD-8 Hub – 34% efficient

Lighting Test Averages (Four Different Dynamo Lights):
SON28 Hub – 44% efficient
3D32 Hub – 37% efficient
PD-8 Hub – 31% efficient
UR700 Hub – 30% efficient

You can read the full dynamo hub efficiency results HERE.

Schmidt SON Dynamo Hubs (3W)

Schmidt is the industry standard for dynamo hubs in terms of both efficiency and reliability. These German-made hubs are also the most expensive. Despite this, they’ve been my dynamo hubs of choice since 2008. The bearings are not expected to need servicing until well after 50,000km due to a combination between robust weather sealing and the high-quality SKF sealed bearings (I’ve never actually had to replace the bearings in any of my hubs). Included with Schmidt hubs is a five-year guarantee too.

Schmidt hubs have been tested to have the lowest resistance without a device or light connected – just 1.4 to 1.9-watts of resistance (10-30KPH). And with a light or USB charger connected, they generate the lowest drag of all hubs, resulting in a charging efficiency of 57% and a lighting efficiency of 44% on average.

Quick Release
SON28 non-disc – 32, 36h
SON28 disc – 28, 32, 36h
SON28 Tandem – 40, 48h
SON28 disc 135 – 32h
SON28 disc 135 VR – 32h

Thru Axle – Disc
SON28 12mm – 28, 32, 36h
SON28 15mm – 28, 32, 36h
SON28 15mm Boost 110 – 32, 36h
SON28 15mm 150 – 32h

Shutter Precision SP Dynamo Hubs (3W)

SP dynamo hubs are the lightest dynamo hubs available and are also quite modest in price. The latest generations are known to be very reliable, but unfortunately, they’re not the best performers – they have a lower rate of efficiency and power output compared to other hubs. That said, SP makes some unique hub configurations you won’t find elsewhere, including for road bikes with a low spoke counts (20 and 24-hole). In addition, their 15mm thru-axle hubs are literally half the cost of a Schmidt. SP gives you the choice between brake rotor mounts on many hubs: 6-bolt (eg. PD-8X) or centerlock (eg. PL-8X).

Quick Release
PV-8 non-disc – 20, 24, 28, 32, 36h
PD-8 disc – 20, 24, 28, 32, 36h

Thru Axle – Disc
PD-8X-M 12mm – 32, 36h
PD-8X 15mm – 32, 36h
PD-8X-110 15mm – 32, 36h
PD-8X-150 15mm – 32, 36h

Shimano Dynamo Hubs (3W)

Shimano makes the majority of the world’s dynamo hubs, so it’s safe to say that they know a thing or two about them. Shimano hubs are very reliable, serviceable and usually the cheapest too. On top of that, they’re brilliant performers. The latest model, the UR700, is the most powerful dynamo hub available (highly recommended for off-road or hilly regions), while the rest of the hubs work out to have the second-best charging and lighting efficiency.

The Deore LX and Alfine models are essentially the same, while the Deore XT dynamo hub sheds 56 grams thanks to an aluminium axle and coil. The top-of-the-line dynamo hubs (UR700 and UR705) save a further 30-50 grams.

Quick Release
Alfine S501 disc – 32, 36h
Deore LX T670 non-disc – 32, 36h
Deore LX T675 disc – 32, 36h
Deore LX 3N72 non-disc – 32, 36h
Deore LX 3D72 disc – 32, 36h
Deore XT T8000 disc – 32, 36h
UR700 disc – 32, 36h

Thru Axle – Disc 
UR705 12mm – 32, 36h

KT Dynamo Hubs (3W)

KT has recently released a dynamo hub range including a hub with a rather innovative end-cap design. By switching out the end-caps, you’ll be able to interchange your dynamo wheel between bikes that employ QR, 12mm or 15mm axles. You can get the hub in either the standard 100mm hub width or to suit 110mm Boost forks, and the disc brake hub models are available with 6-bolt (eg. KD5F) or a centerlock (eg. KC5F) brake rotor mounts. KT hubs employ the same hub shell as the SP Dynamo hubs, although internally they have their own circuitry which is yet to be tested for output power, drag, efficiency or long-term reliability.

Quick Release
KD6F disc – 32, 36h
KV6F non-disc – 32, 36h

Thru Axle – Disc
KD5F 9mm 12mm 15mm – 28, 32, 36h
KD1F 9mm 12mm 15mm Boost 110 – 28, 32, 36h

Note: the KT KD5F Dynamo is rebranded under the manufacturer “TFHPC”.

Kasai Dynamo Hubs (3W)

Kasai has released a hub called the FS Dynacoil. While most dynamo hubs are sealed at the factory and cannot be repaired yourself, this dynamo is field serviceable. Using a 36mm flat wrench, you have access to both the coil assembly and hub bearings. That means that if your hub stops providing power, you can replace the coil assembly yourself (hopefully under warranty) without having to re-lace a new wheel. In addition, when your sealed bearings inevitably wear out, you can replace them too.

Like the KT hub, we don’t yet have any idea how durable the Kasai is, along with its output power, drag or efficiency data – but Kasai is claiming 72% efficiency at 10mph (likely using a resistor). The hub weighs between 445 and 495 grams depending on the model.

Quick Release
Dynacoil FS non-disc – 32h, 36h
Dynacoil FS disc – 32h, 36h

Thru Axle – Disc
Dynacoil FS 15mm Center Lock – 32h, 36h
Dynacoil FS 15mm 6-Bolt – 32h, 36h

Other Dynamo Hubs (3W)

Biologic Joule 3 Disc – Re-branded 32h Shutter Precision PD-8 hubs in silver or black.
Exposure Disc – Another re-branded 32h SP PD-8 hub available in a package with the Exposure Revo dynamo light.
Love Mud Juice Disc – More re-branded 32h SP PD-8 hubs!
Neco Rove Disc – The claims are pretty lofty for this 933g dynamo hub with built-in USB charger – 15W of charging potential (5V@3A). Unfortunately, the testing has shown that you need to be going 50KPH to achieve that figure and that it isn’t at all competitive below 25KPH.
Sanyo H27 Non-Disc – This is one of the best value dynamo hubs going around. Unfortunately, it has a lot of drag compared to other hubs, even with lights or USB chargers switched off.

Learn About Dynamo Hub Systems HERE, About Buffer Batteries HERE, About USB Chargers HERE and Dynamo Lights HERE

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