LED Bikelight V2

by joe

37K5620

Intro: LED Bikelight V2

This is version 2 of the LED Bike Light system. After using version 1 I came to two conclusions:

- They have perfected the LED rear blinky light, don't make your own unless you really want to (I like the Blackburn Mars 3.0 )this is not to discourage you from making your own if you really want to, I'm just saying this blackburn light is bright.
- The headlight is crazy bright, and can be brighter...

This version just has 15 more LED lights, a hi/lo switch and foregoes the rear blinky part.

STEP 1: Parts

33x 55,000 MCD White LED
DPDT Switch
9v battery snap connector (if needed, my 8aa battery holder needs it.)
8aa holder.
Reflector mount.
Breadboard ( I used the PC-403)

STEP 2: Solder

I am using 8AA which is 12v. (8 x 1.5). The LEDs work from 2.8-4 volts so you will want to solder 3 in series.
I used 6 sets of 3 for the "low beam" setting. Start with the positive on the outside and ending with the negative in the middle. This is important because you will do the same for the next set of LED's so you can share one negative, just for cleaner wiring.

Solder the bottom set of 5x3 LEDs the same way.


Solder the positive wires all together for the top set, and the bottom set.

Run a wire from the positive to the middle posts on the dpdt switch.
Run one wire from the top post to the top set of 6 leds. This makes the low beam setting.
Run two wires from the bottom posts, one to the bottom set of LEDs, the other back to the top set of LEDs.

Cut a 4 feet length of wire back to you battery back, connecting the negative to the middle/negative wires on the circuit board. Now you have a hi/lo headlight.

STEP 3: Reflector Holes.

Drill two holes for your reflector mount, and secure with nuts and bolts.

STEP 4: Done.

check out the pics for hi/lo beam action.

20 Comments

jeroenvdd 14 years ago

So what do you do when it rains :D

Jayvis Vineet Gonsalves 14 years ago

Could you please tell me how many lumens does your headlights produce and could you please post an image of it lighting up a dark road? : )

me! 15 years ago

what sort of battery life does this manage to pull?

Myself 17 years ago

Are you using the batteries' internal resistance for current limiting? That might work fine on carbon-zinc dry cells or alkaline cells, but the common rechargeables (ni-cad and nimh) have incredibly low internal resistance and will happily dump their charge at 10C or faster, frying your LEDs after not much on-time.

Since you're running parallel strings and haven't carefully sorted the individual Vf figures of each LED to come up with balanced strings, you should really have individual dropping resistors per string. They can be fairly low value, just an ohm or two if you can get 'em. If these are omitted, you'll likely end up with a situation where one string, because of Vf variations in the LEDs, passes more current than the others, and since LEDs have a positive temperature coefficient, begins to take even more current, eventually destroying itself.

It looks awesomely bright in the meantime, though. :)

babylonfive 17 years ago

You hit it right on the head, if you do say so, Myself. </humor>

The lack of resistors or a current controller will ultimately fry this design, but until then: "FLAME ON!"

I liked the design where the whole board and part of the LEDs was encased in plastic, allowing all the LEDs to generally be at the same temperature and avoiding the thermal runaway action that would lead to a burn out.

My .02$

n0ukf 16 years ago

The plastic of the LED lens/body and the air space between (or anything else that might be between them) is not thermally conductive enough to protect individual units from thermal runaway.

trebuchet03 17 years ago

I was thinking the same thing... but s/he didn't have any problems with the last version, so the batteries must be doing the trick :P

royalestel 17 years ago

It's okay to guess that it's a he. We won't shun you if you happen to be wrong, though most Josephines shorten it to Jo . . .

y2kkmac 16 years ago

wow, that looks really bright. I think that if the LEDs in the bottom two rows were tilted down and the bottom three rows were lit for the low beam instead of the top three it would be better. Great job, by the way!

JakeManes 16 years ago

I like it, but I dont like the idea of burning the corneas of someone driving. But then again, I hate people who cut me off on my bike, and then I look over to see them on a cell phone. Thats why I bought an AirZound bike horn. Loudest horn ever. Theres nothing like letting your anger out by scaring someone crapless with a super loud horn blast. Look up AirZound on youtube, I guarantee youll want one after you see/hear it.

callmeshane 16 years ago

Hmmmmmm I think it's great as a prototype... But I have to do lots of traveling and this includes getting on and off bus's and all with my bike (in the cargo hold).. So I was thinking that the design would be better if it had a solid base - say some 4 or 5mm thick aluminum, and this was mounted to the bike, and that the LED's were mounted into what I call a "high probability of protection" mounting.. I mean perhaps cutting a sheet of aluminium, so you have a square or round base, AND design it to have enough spare metal to fold up around the sides of the LED unit, to project forward of the LED's... by about 6mm - so to protect them from most knocks and most impacts.... And I'd be putting the switch at the REAR of the unit, instead of in amongst the LED's on the blind side of the device.... Anyway.. kudos for trying, now make it bettera.

red_metallic 16 years ago

Kudos on using the project board. That was worth the click to this instructable alone!

royalestel 17 years ago

I think this is great--are you planning on an all-weather case for this one?

i make shooting things 17 years ago

cellophane wrap makes a quick water proofing although it may cause heat problems but I don’t think it will since their LEDs, hot glue works good too (most of the time).

Ignacio_Ramirez 17 years ago

The great problem I see with this design, other than the lack of resistors, is the exposure: My own bike light includes Crazy Glue, silicone and clear vinilic paint and it still rusts. Of course, Mr Joe might hail from Central Australia or somewhere on the Sonora or Atacama Desert and not ever have to worry for rain or humidity, but here in Cancún the humidity never goes below 50% (in fact, it rarely stays below 65%) and I've seen carbon steel knives tarnish to black within two months of receiving a mirror-quality polish and being put on exhibition.