The quest for a bicycle power system

[Garote] has been extremely busy. Busy building an electrical system into his bicycle, and even busier writing a monumental post about it. He covers an impressive range of topics, starting with the goal of adding a generator, battery, charging system, lights, and accessories to the bike. From there he clicks off one thing at a time, researching and ordering a wheel with a Dynamo hub for the generator, assembling and testing the cells of his battery, choosing the controller board for the charging system, and designing the accessory circuits like the iPhone charger above. If he adds too much more to the two-wheeled rig he’s going to have to plan a big road trip with it.

[Thanks Xuxo]


  1. Josxbc says:


  2. afasgfa says:

    20amps from a lithium battery cell??

  3. Haku says:

    I’ve been skimming through some of the pages and have to say it’s an amazing write up! This is a pure HaD article if there ever was one.

    On the power front for bikes, personally I just tap into the battery already on my ebike ;) a 26v 9Ah lithium-ion pack which happily powers my custom, 10 watt, 300 3mm LED front light (using a regulator from dimensionengineering) even when it’s got so low it can’t drive the hub motor.

    @afasgfa, LiFePO4 has an extraordinary discharge capability.

  4. jeditalian says:

    i just need to stick an inverter on mine so i can charge on the go. my phone has crap battery life.

  5. jeditalian says:

    or it would probably be more efficient to step down the already existing DC to usb voltage..

  6. natrix says:

    @afasgfa i’ve heard of lithium polymer batteries that can discharge at 500 amps for short periods of time. i have no idea how they make a lithium cell with such a low esr

    i stopped reading once i saw the usb connections… that’s one of the most hacked together usb devices i’ve ever seen. you figure a smart guy like that could afford a hot air tool to pop off those connectors or to spend the bucks to spin up a board.

  7. mjn says:

    afasgfa: LiFePO4 are often rated for 30C or higher, continuous. However, it looks like these: are the cells he’s using. They’re rated for 5C continuous (50A). Bummer.

    A123 cells are more fun – some are rated for 30C continuous, 50C for 10s bursts. Yowza.

  8. tehbasti says:

    I build SON Dynamos at work :)

    makes me feel good to see that my everyday work is a part in cool projects like this

    cheers from Germany

  9. mjn says:

    Forgot to mention: looks like he didn’t include any means of monitoring the individual cells or balancing them.

    His comment about not needing filtering on the 5V line because it is battery powered is somewhat funny, too. Yes, battery power tends to be quite clean with a constant load. But the 5V is coming from a switching power supply. So not only does the battery supply have a very noisy load on it, but the USB isn’t even coming from the battery. Bleh.

    His section about battery chemistries was fairly inaccurate as well.

    I was curious to see his enclosure design (as a lot of people really mess that up…) but he doesn’t seem to be done documenting it.

    Definitely a hack though, and a decent one at that. More like this. Less Arduino.

  10. Ben Wright says:

    I think he should of built it into a backpack/ something removable. I doubt he leaves his iphone on the bike when he parks the bike. It’s a big writeup, but he got carried away for what he thinks he needs for his Mt. Everest bike ride.

  11. alex says:

    hey, im sure someone probably posted something along these lines, but the pliers seem a bit out of place… but then again hey whatever works.

  12. McSquid says:

    I have that exact same vice grip and its in exactly the same condition.

  13. error404 says:


    He also mentions the ferrite beads several times, but if you look at his wiring job, he’s connected directly to USB pins 1 and 4, bypassing the ferrites. Oops.

    Great writeup otherwise, I wasn’t aware of those TI switching regulator modules, and they look very handy and are pretty reasonably priced ($12/ea) if you don’t go the scam-a-sample route. There’s factual inaccuracy here and there, and he really should have a proper battery controller in there, but nevertheless a wealth of information for newbies.

    More like this.

  14. Glen says:


    Me Too !

    no workshop should be without one :-)

  15. strider_mt2k says:

    The vice grips are like…a sign that he’s a regular guy. :)

    Yes, I believe I have a pair like that too.

    Interesting stuff, especially since I’ve been considering taking up mountain biking again.

  16. Josh says:

    lol this looks pretty awsome!

  17. KC8RWR says:

    Reading the part about charging an iPhone made me wonder how long it will be before he tries to plug in an iPad or some newer generation iPhone and it doesn’t work. He should read this

  18. osgeld says:

    thanks KC8RWR we would have never noticed that 2-3 post down on the homepage

  19. luke says:

    where can i buy a tune charger? someone please tell me a link or something. :) thanks in advance

  20. jeditalian says:

    yeah, i was gonna say: VICE GRIPS FTW!!!

  21. bob says:

    Nice video of Steve Roberts. He’s now doing similar things with a boat:

  22. kimomenu says:

    See that the Tunecharger isn’t for sale anymore. Does anyone know where to find the tunecharger?

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