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Kit Review: hub dynamo and battery pack

Review of the PedalPower+ Hub Dynamo & V4 battery pack – by Chris Leakey

Before setting off on our cycling trip I was keen to be as self-sufficient as possible, not only by taking a tent for accommodation and a stove to cook food, but also for electricity to power all the electrical devices that we would be carrying. After some research we approached PedalPower+ and they were kind enough to give us a discount on their hub dynamo and V4 battery pack. These combined, allow us to keep our ipod, phone, rechargeable batteries and any other small electronic device charged and working wherever we are. I have since found other companies that are doing similar things. However I have no direct experience of these so my review will concentrate around the PedalPower+ products.

Bicycle dynamos have two main forms, the hub dynamo and bottle nose. Both work in a similar way by transferring some of the kinetic (moving) energy you create when cycling, into electrical energy that can be used to power something small, usually about 5 volts. Traditionally this electrical energy has been used immediately, powering bike lights, but with the Pedal power system you can store this energy in a battery pack and use it later when you actually need it.

PedalPower+ AC Hub dynamo

  • Rating 6v3w, Output DC 5v to 600mA
  • Standard 36 spoke configuration 14 gauge
  • Super free running, Weight 750g, Sealed bearings
  • Flange to Flange 92mm, Axel 92mm or 3/8″

The dynamo is built in to a hub, to fit this you can either replace your current hub or get a new wheel built. It looks the same as a normal hub and I hardly notice any resistance with the dynamo. I was surprised as this as many people were very doom and gloom about all the energy I would be wasting with a dynamo. From the hub dynamo you attach a cable that converts the AC power into DC power (that most small electronic devices need). The PedalPower+ universal cable can be attached to other dynamos to use with the V4 battery pack, or can charge small electrical items directly.

V4 battery pack

  • Capacity 5600mA
  • Input 5V 2000mA
  • Output 5V
  • Voltage 3.7V

This is a small unit, about the size of two cassette tapes, that stores all the energy. It takes about 10 hours of cycling to fully charge the V4 or less than 2 hours with the mains fast charger. The battery pack has four output points, one usb and three others that you connect cables to. The cables have interchangeable tips e.g. ipod or Nokia phone, allowing you to charge most small electrical devices.

We have used the dynamos and battery packs for 14 months now and have cycled 8000km with them. It is lasting well and I am hard on kit use. I did break one of the cables early on but this was due to it being inadvertently bent in my bar bag. It was easily replaced and I have rearranged my bar bag to stop this happening again.


  1. Can charge small electrical devices anywhere, no need to find mains power.
  2. Don’t need to be an electrician to get it to work.
  3. Charge directly from the dynamo.
  4. V4 PedalPower+ cable works with most hub dynamos.
  5. Works in the rain and when there is no sun.


  1. The initial set up with the connecting cable is fiddly but you only have to do this once.
  2. Does not power bigger devices such as laptop, netbook or DSLR batteries.

If you have experience of other systems for powering electricals when cycling then please comment below. Check out some of the other gadgets we use here.

Learn more about Chris and Liz’s trip here.

Are you a gear geek? Want to review a product here? Get in touch!

This post first appeared on the Bicycle Travel Network.

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  1. Steve Dowling Posted

    Very cool. We’re thinking of a mini-trip to Amsterdam next year and this could be a great way to make sure we have power. I couldn’t see any prices indicated on the website, most of the links I clicked on brought up a “email us” window.

    What’s the going rate for this ?

    • Hi Steve, we got our hubs as part of a sponsorship arrangment at a greatly reduced price, and this was over a year ago. So I will email PedalPower+ and ask them for the current price list with shipping to the UK/Europe.


  2. Matt Wicks Posted

    Nokia have produced a phone charger using a bottle dynamo. I am thinking of getting one, it only costs £25. Any one have experience with this? My worry is that it will only charge Nokia stuff, and wont be compatible with my mp3 player etc

  3. Alex Lockhart Posted

    I imagined, designed, and built this system from scratch (and a lot of solder!) in 2007 for my relatively short trip through Mexico in 2008. At the time, I was the only person I’d found doing such a thing, despite copious research. I knew of one other person using “normal” solar panel/charger/battery system to achieve a similar end, though.

    Mine was based on a Schmidt SON, Tunecharger, and large custom Li-Ion battery pack. I also designed and built my own LED headlights and taillights with custom beam shape, running from the system power. The system was designed to power the lights, plus charge batteries for my laptop, camera, GPS, flashlight, etc. It worked very well, and aside from the laptop, was more than sufficient to power everything sustainably. However, it was insufficient to completely sustain the laptop, and had to be recharged from mains power every so often. I was using a cheap Dell 15″ laptop, which for reasons of electrical wizardry had to be powered by an inverter, and the power needs of the laptop and inefficiencies of multiple power conversion drained the batteries faster than my 4-6 hours of pedaling a day charged them. I used the laptop for 30-60 minutes each night to write journal entries, and the bike power system effectively served as a power extender, giving me 3-5 days’ extra use beyond the laptop’s regular batteries. It turned out to be sufficient for actual usage, since I was never more than 5 days between a place I could recharge everything, sometimes just on a lucky lunch break. Details are on my site.

    The PedalPower is the first commercially produced system I’ve seen which is similar to mine. They use the Shimano dynamo, and their charging/discharging circuit is very elementary, discarding most of the potential of the dynamo. As a reference, my dynamo was rated for the same output, my battery pack was over 3 times larger, and my “full” charging time was about the same – 12 hours. Still, it’s very useful for its intended purpose, capable of doing exactly what it promises, and has obviously proven its durability on tour.

    Seeing this, as well as recently finding many other tinkerers now doing similar systems (some directly inspired by my design) and some European companies like Tout Terrain producing small USB dynamo chargers (with no extra battery) is very encouraging – many people are obviously starting to see the same need, and potential solution. Perhaps when I build a new system and set out again, I’ll be able to purchase more of it intact, and spend less time at the workbench. Besides improving efficiencies, the only design change will be the addition of a small solar panel to boost the power input and allow me to take a camping rest day and maintain power.


  4. Thanks. Been working as an electrician for a little while now so this post is very useful.

  5. Hi

    Sorry for the delay with this but here are the prices

    The DC dynamo sets are Euro 180 and include the DC cable, piggy back connector set and adapter set. Riders who want to use the iPhone must also use the v4i battery pack

    The AC dynamos are Euro 89, they are 36 spoke hole and are not available for disc brake.

    The rest of the prices are here

    If you mention me Chris Leakey and you will get a 10% discount on quoted prices. If you have any question please fell free to email me or check out the Peddle Power web site

  6. If you take a bridge rectifier with a large capacitor and hook them in series to four AA batteries you can get the same effect as one of those hub chargers for a boatload less money. The electronic parts can be had at radio shack for about $8, throw in a double pole double throw switch for $4. The batteries will burn out after about 4000miles. This system switches between charging the batteries and running the dynamo lights.

    Now, if you are trying to run a laptop off this forget it, most laptops use at least 50-90 watts per hour and the hub dynamo only makes 3 watts per hour. You can make it work with a solar panel sysem though, check out the bike the guy made at caveman astronomy. (Staff section)

  7. Excellent product and service.

    I experimented with homemade circuits for charging batteries/devices from solar/dynamo but I couldn’t make them robust enough for dirt road touring and they needed constant repair.

    I ended up buying a Pedalpower universal cable and v4 battery pack. I couldn’t get the v4 to charge using the universal cable (possibly because the output voltage of my dynamo was below the input tolerance of the cable) so they replaced it for free with a Super-i-cable! Now everything works fine and it has survived some very rough roads. A worthwhile investment.

  8. Another PedalPower+ owner here, but I have the PedalPower+ Super-i-Cable married to a SON 28 dynamo. I have had mixed experiences to date with the Super-i-Cable, probably in part due to my expectations but also I may have a problem unit. Unfortunately I haven’t had any luck getting a response out of PedalPower+ which is disappointing.

    My expectation was that at least at times I would get sufficient power to run my lights and also charge the PedalPower+ Super-i-Cable but that does not appear to happen (no hub light).

    However, my bigger concern is that the Super-i-Cable will not charge my Google Nexus S which charges fine in other contexts via a mini-usb cable. It seems that PedalPowers+ statements about smartphones and Samsung phones are not playing out with mine.

    Hopefully I will get it resolved soon.

    How is V4 going? Can you run your lights and charge at the same time for example?


  9. Hi
    I have used, or try to use the Nokia phone charger, and it is great if you have a basic phone. I found that my N8 smartphone would not charge at all.

    After various conversations with Nokia technical team, I was advised that my phone and most smartphones will need more power to charge. It was finally worked out that I would need to be cycling 30mph for it to start charging.
    That was way beyond you average speed for touring so sent it back.

    After various searches later, I found a company called ‘Tigra’ that do a bike charger. It’s a bike light and USB power charger. I think it starts charging my smartphone at about 10mph. It even had an on/off switch.

    I have used this for a recent cycle trip and it did the job perfectly. It’s the only one I have found to do the job. I bought mine about a year ago for about 50 quid.

    I am not clever enough to build my own from loads of wires from an old fridge and some rotting veg!!!

    • Darron Posted

      Please ignore my advice about buying the ‘Tigra’ bike light and power charger.
      After changing my phone to a model made this part of the century, the Tigra not only knacked my phone with the unregulated power, but also wouldn’t charge my phone.
      Don’t get me wrong it’s great for a bike light and basic phone charger (chargering basic phones, not a basic phone charger). No decent phone will work with the though.

      • Steve Holland Posted

        Suggestion , just use the Tigra to charge a small cheap usb battery pack designed to charge phones (about £10), and then plug the phone into that, either off or on the bike. Adds versatility of an independant battery to charge in tent etc. Done this with a roller dynamo with very unregulated power and works a treat. Quick question, can the Tigra be used with front low rider pannier racks?

  10. Hi, here it is a Tigra dynamo user. I installed it on my bike the last week and tried to use it on a mountainous terrain. I found out that the climbing speed was enough to make the device work, but also found out that the descent speed (about 40-50 km/h or 25-30 mph) for about 10 kilometers (6 miles) was enough to burn out the chipset. I also found out that this device has only a guarantee of one week, a ridiculous one for a product of 129$. My conclusion using this product is to suggest not to buy it, at least if you live in a mountainous country.

  11. Myrddyn kruse Posted

    Just a quick question.can the v4 battery charge a phone while also at the same time being charged by the hub.iv had problems with the charge dropping when going up hill so I was wondering is the answer to this.



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