Homemade Halogen Bike Light





Introduction: Homemade Halogen Bike Light

This is a bike light I have made because of the fact that the commercially made versions are way too expensive for my needs and I thought it would be fun to make! I'm using a 20W 12 volt bulb and two R/C car batteries rated at 2000ma/h and are 7.2 volts each. I linked them in series to double the voltage so effectively I'm 'overvolting' the bulb which does in turn reduce the life span of it!

Check the photos for a more detailed insight on how its put together-------

Step 1: The Bulb Casing

The bulb casing is actually a piece of PVC piper joining and some how fits perfectly with a halogen bulb when the end cap is screwed on (cap not shown here)

I used a bolt with a square shoulder for the clamp so that it didn't spin inside the casing, the hole in the piping was drilled out then the square was formed with a sharp craft knife.

Step 2: Clamp Assembly

The bolt is pushed through the PVC piping and a nyloc nut was screwed on to lock the bolt. Then another nut was screwed on, then the brass clamp was screwed on. I made some adjustments to the bolt length so that the thread did not poke out of the brass clamp. Finally the second nut was tightened up to the brass clamp so nothing was slipping,

Step 3: Battery Casing

Yes, I did actually make this case from scratch from pieces of aluminium lying around in my garage fixed together with pop rivets and nuts n' bolts. You can use anything you want for this, as long as it isn't too big but still houses the batteries and connections. I have yet to make this box watertight, and will be sending pics once I have a solution, oh, and a lid for the thing. As you can see the cable coming out of the box has already been sealed by using sealant glue (can use glue gun, or whatever is suitable).

Step 4: Battery Connections

For this part I have used cannibalised jack sockets from an old mixer. I then used some angle aluminium and drilled holes big enough for the sockets. The sockets were installed then I used double sided sticky pads to attach the bracket inside the battery case. The jack sockets have two terminals each. I simple made copper wire jumpers to link both together and and then soldered the two core cable so I had one positive and negative connection. Basically its in PARALLEL connection. Glue gun was used just to insulate the wiring.

Step 5: Bulb Wiring

An old halogen bulb holder was used. This one has separate screws for wires to fed inside. The tiny grub screws are to tighten the bulb into the holder. I used a random push switch and a phono (RCA) socket for the battery cable connection and those were fixed in a extended pipe cap as shown in pic. All was soldered and then insulated with electrical tape. Pretty bodge!

Step 6: Finished!!

Basically you can make a lot of what I made to however you want it or however you can make it, the bulb casing was put together by tightly screwing the pipe caps on with the halogen bulb inbetween one of them. The rest is pretty much self explanatory from the pictures, Thanks for looking at my approach/ solution to a cheap and effective bike light

SO I now have pretty much finished this dam thing and its pretty awesome! I have scrapped the aluminium battery housing and gone with a simple water bottle case instead- which is lighter and much easier to mount because its ready-made.

I've got new Nimh batteries rated 7.2v 2000mah (�13 each) each and are running them series to get 14.4V. The bulb and housing/mount are the same. The end cap on the housing doesn't have a switch anymore. I am just using the plug connectors as a switch- less components to go wrong! Oh and some new wire too (good ol speaker wire)

Check out the pictures (phone quality i know, will take some better ones some time)




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    These are awesome to have, just be careful not to blind cars going by :)

    hi there

    1) might be a year late ....can you please advise on run time for this light in terms of hours or total minutes.

    2) in terms of one 7.2v battery ...whats the rating of the wattage output >?

    many thanks.

    Do you know what that type of clamp is called? I have not seen one made like that. It looks very strong.

    2 replies

    Hi there,

    I think its just a pipe clamp, can't remember the size of it though, made out of brass. All the holes are threaded too. I reckon its just for household copper piping so just look in your hardware store and something similar will probably be found in the plumbing section perhaps.

    Cheery ho,


    Thank you. I will look in the local hardware store. That gives me a good idea of where to look. :)

    i like this, high mA, potencial for lightweight, but im sorry, sticking to my halogen cygolight

    3 replies

    Oh, a dynamo would be driving that hopefully to get rid of batteries!

    OK forget what I just said, read my updates people. Its ready to go!

    this might have a place mounted above the caltrops deployer lol

    I did something similar to plug into the "12V" electrics of a Honda Caren (50cc twist 'n' go moped). I found that the bulbs were overdriven & didn't last too long, but you're not going to get much more than an hour out of your battery? See pic:

    1 reply

    ...and I would post an instructable, but there's no way I'm doing all that papier-mâché again...

    By aiming it properly, you mean directly at the windshield? You can't really blind a car, more like the drivers, my bad. As to how legal riding into oncoming traffic is, what if you we're riding the right way down a one way street, and some driver came the wrong way along the street, technically, you'd be running into oncoming traffic legally... I stand by what I said with the 500w bulb...

    I think you mean you wired it in SERIES to double the voltage. Parallel wiring would double the battery life. You mentioned that in the intro.

    1 reply

    Thanks guys for your replies, corrections have been made and also the batteries are only the Ni-Cad type! Yeah i've got to sort out the circuitry first before I can rely on it, its being a bit temperamental! Then I can adjust it on the bike, tested it out in the dark in my house and its pretty dam bright, lights a whole room!

    My suggestion would be to avoid this wussy light, and hook up 25 r/c car batteries with a 500w halogen light. That way, you can blind oncoming cars. You could possibly also hook them up to a motor for added speed. Good instructable, what type of batteries are they? Please tell me Li-Po, this would be a good use for left over Li-Po batteries, now that most races don't allow them, as they tend to explode...

    1 reply

    Something tells me that if I were riding into oncoming cars (which would be illegal) ... I wouldn't want to blind a high velocity 2 ton hunk of metal/plastic/etc. I think someone else used high wattage bulbs -- just aim your lights properly :P