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!
<p>I know this. Works perfect</p>
Awww!<br /> I was hoping it would charge via the pedals or wheels...<br />
<p>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.</p>
<p>Would that be a TL28 on the table</p>
<p>Good eye!</p>
i like it. This is going on my bike very soon
back @ you man!
No no no, you see, its a dynamo-charged rechargeable battery, so you do not need to replace them.&nbsp; Just crank the dynamo to recharge the internal batteries.&nbsp; This is pretty cool, now imagine if you attached a cable from the dynamo to your wheel!&nbsp; (hands free charging)!!
Yeah, then you just have a normal light like found on about every bike.&nbsp;
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&nbsp;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!<br />
Yeah, um these do have batteries, they just recharge.
Are you positive?&nbsp; I was told it was a capacitor.<br /> Of course I may be wrong, and that's cool.<br />
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.&nbsp; <br /> Since it was featured,&nbsp; I'm not going to edit it.<br /> <br />
It doesn't bother me if you edit it or not, I just like solving little misunderstandings and helping people understand how things work.&nbsp;
&nbsp; I thank you because I learned more about it......I went ahead and edited it anyways because it was wrong.&nbsp; I'm also new here and thought I could not edit once it had been featured.<br /> &nbsp; Stay on point, please.&nbsp; I WILL do more stupid stuff in &quot;public&quot;!<br />
<span class="medium_text" id="result_box"><span title="Sea como sea, con o sin bater&iacute;a, es un excelente instructable.">Anyway, with or without battery, is an excellent instructable. </span><span title="Y si hay bater&iacute;a, pero se carga a mano, bienvenida sea.">And if there are&nbsp;</span></span><span class="medium_text" id="result_box"><span title="Sea como sea, con o sin bater&iacute;a, es un excelente instructable."> batteries</span></span><span class="medium_text" id="result_box"><span title="Y si hay bater&iacute;a, pero se carga a mano, bienvenida sea.">, but they are loaded by hand, are welcome.</span></span>
hold it <br /> so this is a<span class="stepTitle"> &quot;Battery free bike light</span>&quot; <br /> with a Battery in it ??????<br />
I'm no tech, but I do believe that the dynamo charges a capacitor.<br /> In the picture you can see it in blue shrink&nbsp; wrap.&nbsp; <br />
Why would they shrink wrap a capacitor? I bet that you can see a line sticking up from one end to the other, which is a wire underneath. I can almost guarantee that if you rip/cut that open there will be button cell batteries.
i agree, i know he probably means no batteries needed to be inserted, and i understand that that doesnt fit in the title, but its also kind of deceiving...<br /> <br /> but its a nice idea, nice instructable, and it works pretty good i think ;)<br />

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