DIY LED Tail Light?

[loply]

Hi folks,

The bulb holders on my Milles tail light are a bit gnarled (barely make contact) and each time I replace the bulbs they become more sensitive. I've fiddled with them but its a bad design and supporting plastic is snapped/missing, making it hard to fix. Now one of the bulbs won't come on reliably and the other is suspect too. It makes me nervous at night incase they both suddenly go off.

A new holder is £45 from Aprilia. I'm thinking instead of hacking the bulb contacts off and soldering/epoxying in a bunch of LED holders and hooking up some ultrabright 12v LEDs instead.

There are three wires going in... I guess one is ground, and there's one each for tail and brake, right? It should be easy enough?

Anybody see any pitfalls or potential problems here? My idea is to use two bright white LEDs in place of each bulb filament, ie two for the tail and two for the brake... But there's two seperate light pods so that means 4 LEDs for the tail and 4 for brakes in total.

I'm going to pull out the copper contacts and epoxy in a cluster of LED holders where they go, then solder it up as required.

Should be bright enough? Can't see why its not surviveable, should last easy enough? The lights are covered with a red lens so I presume I should just use white LEDs?

Thanks for any tips or wise advice.
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[Ichy]

All sounds fine. Wires are as you said. Just remember that you will need resisitors as well.

I guess one other option is to buy some led tail and brake bulbs, solder the wire directly to them and epoxy in position. I got some cheap, £3 for 2, ones off ebay and they were just fine.
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[loply]

Presumeably if I wire the LEDs in parallel I can just put one resistor on the ground for each light pod connector thing?

I've forgotten how to calculate the size of that resistor mind but I'm sure I'll figure it out...
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[loply]

Aye I see you can get them on ebay for real cheap, probably costs less than buying the LED's from Maplins!

That's a better option, then just solder and epoxy in position as you said....

Presumeably they should last virtually forever? Obviouslly once it's done it'd be a pain to change...
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Yamaha SZR660 Caution to the wind, the throttle pinned!

[mikey 2659]

please be aware that led replacements as used by spotty boy racers are illegal for on road use and may get you in bother with the plod,also ask your friendly mot station tester what would fail.

[KevTM]

^ if it's just tail lights/brake lights there's not much to go wrong. I think the whole LED problem is with front facing lights, not being white, more of a blue colour etc etc..

I have a modified tail/brake light unit taking from a bus on one of my Bandits.. Works a treat and passed 2 MOT's without any problem.

[mikey 2659]

each led needs about 2 volts limited to 20ma to light.4 led's in series equals 8volts,12 volts in minus 8 volts equals 4 volts,resistor equals volts(4)divided by current(0.02amps)equals 200 ohms .preferred values are 180 or 220 ohms.you cannot usually put led's in parallel as they may vary in brightness.wire one circuit of led's to the tail circuit then a second resistor from the the stop wire to the junction of the first resistor and the diodes,when the brakes are applied the led's will double in brightness.the diodes are polarity sensitive.dont forget to illuminate the number plate.

[Phoenix]

LEDs are usually between 3.2 and 3.7 volts not 2. On a 12V system you can get away with running 4 in series as 3v usually gives them near full brightness and remember your circuit actually runs at about 14.5v most of the time, though you'll need bigger resistors so the cheapest and best way is to wire them all in parallel using a small resistor each. When you buy a pack of LEDs they usually supply you with an equal number of resistors to run off 12v included with the price. The only downside of that method is it takes more space to put loads of resistors in.

As he said, you need to remember that most rear lights have a clear section underneath to light the numberplate so you'll probably need some facing down aswell.

LED bulb replacements aren't going to cause you any problems with MOT or Police, blue led's in your windscreen washer jets may but that's totally different.

[adamck]

have a look in dealextreme.com its a USA company based in china that sell all kinds of LED stuff including bulbs and strips etc...
Im sure you may find something on there which you can use?
They do LED cluster bulbs in superbright which may be of use?
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