Battery "free" Bike Light.





Introduction: Battery "free" Bike Light.

About: My full time job as an Organ Grinder keeps me pretty busy but that's just small change. My part time work, as a Mohel, keeps me up to date on my student loans from UCLSD.

  Step up and get your own "dynamo hum"...(FZ).  All jokes aside, its a simple dynamo light mounted to a Planet Bike light bracket.  On about 6 cranks I get 20 to 25 minutes of light.
  There is a 3.6 volt NiMH rechargeable battery that comes in the light.  SO, by free I refer to your out of pocket cost on batteries.

Step 1: Material

1. dynamo light....Harbor Freight, 2 for $8.
2. quick release light strap...most have a screw to change the mounting base, this is a Planet Bike
3. super glue
4. fingernail polish remover........or acetone

Step 2: Light Base

Remove the screw and discard the top thin portion.

Step 3: Level Base

Use a knife to take any high points off of the base.

Step 4: Break Light Down

Take the 4 screws out of light.
Be cautious not to let any gears or gear shafts to fall out.

Step 5: "drill" Hole for Screw

Using a hole punch I twist and push a hole through the plastic, working from both sides.

Step 6: Prep for Glue

Using the fingernail polish remover, I clean both surfaces.

Step 7: Glue

1. I put glue on the base only.
2. Screw light cover to base.

Step 8: Put It Back Together

Once glue is dry, put your 4 screws back in and your done.

Step 9: Get Rolling and Give It a Crank!

The law (here in Arizona) says you need a forward facing light visible from 200 yards.  This covers that and I only need a rear red reflector.  So, I'm now battery free!



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    Please be positive and constructive.




    I was hoping it would charge via the pedals or wheels...

    2 replies

    In the 60s there was a light that worked from a power source that was mounted on frame and run the light from the tire.. Do not remember the name but I had one.

    I believe what you are thinking of is a generator.

    The end of he rotor rubs against the edge of the tire. Terrible tech. The faster you went the harder is was to pedal. Stick with batteries IMO.

    I know this. Works perfect

    Good eye!

    i like it. This is going on my bike very soon

    Thumbs up.jpg
    1 reply

    back @ you man!


    No no no, you see, its a dynamo-charged rechargeable battery, so you do not need to replace them.  Just crank the dynamo to recharge the internal batteries.  This is pretty cool, now imagine if you attached a cable from the dynamo to your wheel!  (hands free charging)!!

    2 replies

    Yeah, then you just have a normal light like found on about every bike. 


    but the battery lasts soooo much longer.

    Good instructable . Good not to have to worry about your batteries dieing on your ride . I do recommend having a cheap red blinky light for the rear it be seen much better then a reflector . In the same vein lights or reflectors on pedals make you much easier to see also .

    NICE, anything not to purchase batteries!


    Yeah, um these do have batteries, they just recharge.

    5 replies

    Are you positive?  I was told it was a capacitor.
    Of course I may be wrong, and that's cool.

    Yes, I've taken apart 10 or so of that kind of light. Each of them had lithium ion button cells.

    Yes, you are correct. 
    Since it was featured,  I'm not going to edit it.

    It doesn't bother me if you edit it or not, I just like solving little misunderstandings and helping people understand how things work. 

      I thank you because I learned more about it......I went ahead and edited it anyways because it was wrong.  I'm also new here and thought I could not edit once it had been featured.
      Stay on point, please.  I WILL do more stupid stuff in "public"!

    Anyway, with or without battery, is an excellent instructable. And if there are  batteries, but they are loaded by hand, are welcome.