Introduction: Battery "free" Bike Light.

Picture of Battery "free" Bike Light.

  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

Picture of 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

Picture of Light Base

Remove the screw and discard the top thin portion.

Step 3: Level Base

Picture of Level Base

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

Step 4: Break Light Down

Picture of 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

Picture of "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

Picture of Prep for Glue

Using the fingernail polish remover, I clean both surfaces.

Step 7: Glue

Picture of Glue

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

Step 8: Put It Back Together

Picture of 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!

Picture of 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!


TheZuke! (author)2010-03-08

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

doo da do (author)TheZuke!2016-11-13

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.

kriemer (author)doo da do2017-09-01

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.

delecto (author)2017-06-17

I know this. Works perfect

doo da do (author)2016-10-22

Would that be a TL28 on the table

onrust (author)doo da do2016-11-02

Good eye!

crapsoup (author)2012-08-01

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

onrust (author)crapsoup2012-08-02

back @ you man!

Celt (author)2010-03-07

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)!!

Ganoderma (author)Celt2010-03-07

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

Celt (author)Ganoderma2010-04-23

but the battery lasts soooo much longer.

randomray (author)2010-03-27

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 .

602poop (author)2010-03-10

NICE, anything not to purchase batteries!

XOIIO (author)2010-03-07

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

onrust (author)XOIIO2010-03-07

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

XOIIO (author)onrust2010-03-07

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

onrust (author)XOIIO2010-03-07

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

XOIIO (author)onrust2010-03-07

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

onrust (author)XOIIO2010-03-08

  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"!

rimar2000 (author)2010-03-07

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

thelastonekills (author)2010-03-06

hold it
so this is a "Battery free bike light"
with a Battery in it ??????

onrust (author)thelastonekills2010-03-07

I'm no tech, but I do believe that the dynamo charges a capacitor.
In the picture you can see it in blue shrink  wrap. 

XOIIO (author)onrust2010-03-07

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.

godofal (author)thelastonekills2010-03-07

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...

but its a nice idea, nice instructable, and it works pretty good i think ;)

About This Instructable




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