A dynamo front wheel can now power your smartphone and other electronics using one of several dedicated USB chargers. This article reviews all available charging options and ranks them by power output at 20 kph (12 mph). At present, there are around 30 different USB chargers designed for use with hub dynamos.

Personally, I use the SON Ladelux to charge a range of devices, including iPhones, AirPods, speakers, Kindles, headlamps, camera batteries, and even a Garmin InReach.

This article was originally published in March 2012 but has been updated in August 2026.

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

Comparing 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:

• Dynamo Light – These are dynamo-powered front lights that also function as USB chargers.
• Steerer Integrated – These chargers are built to fit cleanly inside your fork’s steerer tube for a sleek setup.
• In-line – 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 plug 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.

Dynamo Lights With USB Charging

Purple Dog Companion, Stalker & Terra

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

Optimised for road use, the Companion features a soft-coloured 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.

The Purple Dog Stalker is a 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 to around 20% brightness, while the internal battery ensures maximum brightness is maintained even when you slow down or stop.

The Purple Dog Terra is the latest model for low-speed bikepacking, combining the Stalker’s high-beam functionality with a more versatile USB-C power system. It can maintain full light output at low speeds and when stopped, with continuously adjustable brightness from 100 to 700 lumens. It also eliminates flicker across the entire speed range.

The Terra can supply up to 5W to an external device while also accepting up to 7W through USB-C to charge its internal battery. The USB-C input can even be used with a power bank to run the Terra during hike-a-bike sections. Its internal battery is user-replaceable without tools or soldering, and Purple Dog claims a full recharge takes around 1.5 hours when riding at approximately 15 kph.

Speed at 2.5W: 15 kph
Power at 20kph: 5 watts (manufacturer claim)
Power Output Graph: No
Battery: 1600 mAh
Price: €395-440

SON Ladelux

The SON Ladelux is what I’m currently using for my bike journey from Norway to South Africa. Not only is the Ladelux one of the brightest dynamo front lights on the market, but it also delivers great USB charging speeds. Its integrated USB charger is fully waterproof and 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 providing power to your devices when you slow or stop.

Yes, the Ladelux is expensive. But it’s built with the best materials, is designed to last, and can be repaired by SON if something goes wrong. It also offers some of the best lighting and charging, all in one.

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 makes the C1 unique is its 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: £299

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

Integrated USB Chargers

Tout Terrain Plug Plus 7

The Tout Terrain Plug Plus 7 has very sleek integration and strong power output at speeds below 18 kph. It includes a 2200 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 would recommend avoiding using it in downpours and always covering it with the included waterproof cap.

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: 2200 mAh
Price: €299

Forumslader Aheadlader V6

The Forumslader Aheadlader 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: €275

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 Plug Plus 7, 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: €83

Cinq Plug Pure 7

The Cinq Plug Pure 7 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 around 3.5 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: 3.5-watts (approx)
Power Output Graph: Plug Pure 5 HERE
Buffer Battery: No
Price: €99

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

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

In-line USB Charging

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 supercapacitors 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 supercapacitors with four minutes of stationary power
Price: £220

Fahrradlader V4.0

The Fahrradlader V4.0 is a small open-hardware project by an electrical engineering student in Germany. The latest Fahrradlader delivers big power at 20 kph 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 be made only in small numbers (you might need to get your name on a list).

Speed at 2.5W: 13 kph (manufacturer claim)
Power at 20kph: 5.5 watts (manufacturer claim)
Power Output Graph: HERE (manufacturer claim)
Buffer Battery: Four supercapacitors with stationary power
Price: €50

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 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: €179

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 great 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: €175

Igaro D3

The Igaro D3 charger features a USB-C port, 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 worldwide for free.

Speed at 2.5W: 14 kph (D2 model)
Power at 20kph: 4.1 watts (D2 model)
Power Output Graph: HERE
Buffer Battery: No
Price: £149

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 for its reliability and reasonable 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, which is a super-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

Busch and Müller E-Werk

Though very 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: €199

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: €119

USB2BYK

Speed at 2.5W: 20 kph (manufacturer claim)
Power at 20kph: 2.5 watts (manufacturer claim)
Buffer Battery: No
Price: €29

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: €35

Ullmann Power Station 4

Speed at 2.5W: No data
Power at 20kph: No data
Buffer Battery: No
Price: €99

VeloCharger MK2

Speed at 2.5W: No data
Power at 20kph: No data
Buffer Battery: No
Price: £110

BioLogic ReeCharge Dynamo Kit

Speed at 2.5W: No data
Power at 20kph: No data
Buffer Battery: No
Price: US $29

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