DIY LED Brake / Tail Light

[Soliton]

I have been thinking about LED tail lights for a while but my mechanic warned me off them. He has seen a lot of the aftermarket ones fails with whole rows of the LEDs ceasing to function. I sussed out the designs and found that they often use s single resistor for load reduction which opens them up to problems with bad solders etc.

So... Time to bite the bullet and make one myself. It turned out to be pretty easy except for few gotchas.

Here is a bodgy "how-to" for anyone who is interested.

I found 10mm 160,000 mcd 0.5 watt red LED's on eBay prewired with resistors. Make sure you get the type with at least a 40 degree viewing angle. They work out at a bit over $1 each and they are WELL bright. The resistor on each LED means that they run off 12v without any modification and if one fails the rest won't follow suit. Having a single resistor also means that individually they don't get as hot.

One
Open the case (blah, they are glued.) A very fine cutting wheel (and a bit of patience on a Dremel did the trick. You don't need to cut the whole thing open. Cut and stretch gently and you will see where it is glued and where it is just pressed together.

Two
Make a U shaped bracket to hold the LEDS. I made a grid on paper of 15mm squares and drilled out 10mm holes. This gave me 5mm between each LED. I used some ABS offcut for the bracket. It is easier to drill the holes and bend the arms of the U afterwards. ABS bends with a heat gun.
A matrix of 5 x 3 is the easiest and is sufficiently bright for both tail and brake. Glue the LEDS into the holes.

Three
Separate out the wires off the LED's. All the red from the brake in one bundle. All the red from the tail into another bundle and all the black together.

Four
Check the length before your do any stripping/ soldering. When you later put on shrink wrap the wires won't flex as much so be careful not to make them too long.
Pull each group taught and gently tie them with a cable tie. This is so they end up the same length when they are stripped and tinned. (The cable tie comes off later)

Strip 15mm off the end of each wire. Buy good wire stripper! The manual ones, (look a bit like pliers with teeth) are appalling! I only had a manual one and ended up with blisters and plenty of broken wires. A better one would have cost about $30 and saved much heartache.


Five
Join up the wires on each group. You will end up with three, tin the ends with solder, put on spade connectors, solder the tinned wire to the connector (belt and braces) and slip on some 8mm shrink wrap to provide load relief to the wires.

Six.
Glue in the U bracket with the LED. The silver paint onside the brake light housing needs to be lightly sanded back for the glue to take properly. Pass the cables thought the back of the housing. I had to open out the hole in the housing (the one for the globe holder) to allow the wires through.

Seven
Connect up the LED spades with the the spade connectors on the wires going to the old globe socket.
LED black wires to bike brown (ground)
LED brake bundle to bike grey/yellow
LED tail bundle to bike grey / black
Test it!

If the test goes OK (and it should) glue the shell back together with super glue or epoxy. Seal it with a bit of clear silicon to stop the water getting and screw it back onto the bike.

Cost $30
LED's $25
Spade connectors $4
(Most folks have some glue around the house)

Time - About 2 hours. It is a bazillion times quicker if you have a good wire stripper.

You can buy theses pre-made for $60 or so on eBay but I would bet they don't use 160,000 mcd LEDs and they are definitely engineered to a price. (And its heaps more fun to build your own) I had never held a soldering iron before but a quick Google of "how to solder" gave me the basics. Low and behold if you listen to what they tell you it works better! (Why did no-one tell me this when I was young.)

Next stop.....indicators

Have a great time!

[towerworker]

Can you post any pics?

[Xdot]

You've inspired me Soliton! And I already know how to solder. So tell me: where'd you find your LED's???

[rdsmith3]

I've been meaning to try these ... for a few years now

http://www.vlsusa.com/cgi-bin/vlsusa/TIR3.html

[Soliton]

I bought the LEDs from eBay.

They were described as 12V 10mm 0.5W 5-Chips Red LED. The seller was called topbright88. The sale was quick and so was the delivery. (Free shipping too!) I'm not touting for this guy but he/she did a good job and sold me exactly what I was after.

The things to check are that they are at least 40 degrees viewable angle and the model I bought had a 160K mcd output. i rechecked the price and it was $28 for 20 pieces. I used 15 for the job.

[CycleRob]

I am also designing supplemental LED pairs (2+2) for the Stop/Tail circuits, to be mounted into holes drilled in the stock plastic parabolic reflector. They'll work simultaneously with the standard 1157 conventional bulb, while providing extra illumination, without triggering a "LAMP" fault indication from the monitoring system. My do-it-yourself approach was chosen because I do not believe the twist-in aftermarket LED tail bulbs you buy will NOT trigger a failed "LAMP" indicator, due to their very low current draw. Also anticipating better durability/longevity, failed bulb back-up and a unique visual pattern. Have already obtained the 2 bright and 2 super bright LEDs from Radio Shack, the high quality low cost supplier in a Mall near you. Need the correct high power dropping resistors and the time/ambition to complete the job. Will provide the Radio Shack LED part numbers, dropping power resistor values, circuit diagram and relevant pictures when completed. Care is required in the reflector hole drilling as any errors cannot be undone. I am sure it will be completed before Christmas . . . this year.

[michelsmith]

Please share pics if you have......

[Soliton]

I tried the plug in LED globe option (1157 type) and they don't work well, actually they are so dim as to be a hazard.

The globe is angled end on, because of the socket position, and this means that the light is only provided by the SMDs directly on the end. If the mount point was "side to side" the full length of the globe would be visible and the reflector would be able to do its job. The reflectors however are not particularly well made. They are move of the silver paint style rather than the mirror style.

Using the pre-resistorized LEDs avoids the lamp failure issue, and also provides some redundancy i.e. one can fail without affecting the others.

[Soliton]

I will have a go at posting some pictures. Unfortunately I haven't had much luck so far. The site tells me it in "unable to determine the size of the images"

Oh well! Keep trying.

[Soliton]

Here you go chaps. Not the perfect option but here are some pics...

https://www.me.com/gallery/#100028

I will be putting on a hugger eventually and moving the number plate down. I think this should give a cleaner line to the back of the bike.

[Soliton]

Sorry guys, ignore the link above. It seems to be wanting a login. I thought I had set it up to be public. Darned computers.

[Soliton]

OK last try.
http://gallery.me.com/soliton#100028