White LEDs for Neutral and Turn Signal indicator lights

[5th_bike]

Getting fed up with both indicator lights having burnt out twice in less than 4,000 miles, I decided to use white LEDs for the turn signal and neutral indicator lights. Modern white LEDs have a good enough light output to replace the filamented light bulbs that are still used for the indicator lights. So far I have constructed the turn signal indicator light using the base of an old light bulb, and building two LEDs onto it, with some epoxy resin. The procedure is below.

Materials:
- Two white LEDs, I took them out of two Dollar store "reading lights"
- One old burnt out indicator light bulb
- One 1 k? (1,000 ohms) resistor, 1/4 watt, Radio Shack (1/2 W is too big)
- Plastic (epoxy resin)

Equipment
- Plyers
- Knife
- Soldering iron

Procedure:
- Put the light bulb in a paper towel and crack its top part with the plyers, do not crack the base.
- Cut the two wires just underneath the little glass ball
- Keep the base with the two wires sticking up, discard the rest.

- Determine each LED's negative side, indicated by the flat spot in the ring at its base.
- Cut the negative legs to approx. 10 mm.
- Put the LEDs side by side at their flat spots, and connect each negative leg to the other LED's positive leg at about 3-4 mm below the base of each LED. Do NOT have the negative legs touch another, move one to the side, and the other can go underneath.
- Cut the resistor's legs to about 8-10mm and 20mm, solder the short end to one of the LED's positive legs, right where the negative leg connects. Cut that positive leg right underneath where the resistor connects.
- Now there are two wires, one LED's positive leg, and the long end of the resistor. Position these such that they point down (away from where the LEDs shine to) at a distance about equal to the distance between the old light bulb's base wires.

- Scrape the base's two wires clean with a knife, and prime them with the soldering iron and some solder - they tend to not to want to take solder initially, and need some persuasion.

- Cut the assembly's two wires to length, and solder them to the base's wires. The size of the 'new' bulb should not exceed the size of the old light bulb, the assembly may need a little twisting/compression.

- Test with a 9V battery, depending on the polarity of the battery one LED at a time should be 'on'.

- Mix up some plastic (epoxy resin) and fill the space between the base and the LEDs. Hold it by the base, and twist and turn it to keep the plastic blob in the middle as it hardens (approx. 15 minutes).

- Harden overnight, and insert in motorcycle.

A turn signal indicator light needs two LEDs because depending on which turn signal is used, current goes through it in one direction or the other. The next light, the Neutral indicator, will only have one LED in series with the 1k? resistor, and if it doesn't work I will just put it in the other way.

Put the LED that is 'on' when the left turn signal is used, at the left side underneath the green lens, ditto for the one on the right, and you will have a 'directional' turn signal indicator light, like I do now

(edit The image below shows the principle of the two LEDs in opposing directions, with the current going in one direction:

[phoenix]

question. dont now much about led's but everything i have read in mags says that you need a um.. um... load balancer or somethinglike that. will you need one for something as small as that?
and thats some good info to know.

[5th_bike]

Originally Posted by phoenix

question. dont now much about led's but everything i have read in mags says that you need a um.. um... load balancer or somethinglike that. will you need one for something as small as that?
and thats some good info to know.

Yes, the resistor is the "load balancer" if you would subject the LEDs to 12V without a resistor, they would blow up. The resistor limits the current to about 10 mA, and LEDs typically can have 20-30 mA, thus.
Edit: Sorry, wrong answer, I had no idea what a "load balancer" is, see below for an explanation by Easy Rider. A load balancer is not needed for the indicator lights.

[phoenix]

cool thx, sounds like ya know yours stuff.

[patrick_777]

Awesome write-up. How 'bout some pics?

[phoenix]

could you do the same thing with other light on your bike but use some brighter led's and maybe colored ones? or is there a lot more to it on break and other ones?

[5th_bike]

Patrick, give me some time please, I'll edit some more and insert some pictures, couple weeks.

Phoenix, there are posts about people mounting LED rear lights and brake lights, search for "LED", this thread is for the two indicator lights.

[patrick_777]

This thread = Sticky.

Phoenix, the brake lights and turn signal LEDs have to have a modulator/resistor installed inline for them to work correctly, but they are not that hard to install. Like 5th said, there are threads here all about them. I'm too lazy right now to search them out though.

[alanmcorcoran]

I was thinking this was a lot of work to save a few bucks until I got to the part where you said you now have "Directional" turn signals. Did you actually put one of the blinker LEDs under the left (green circles[?]) or just on the left side of the right green circle? I have a quick, right, left, right to get on my street and I like being able to quickly tell what side the blinkers are blinking on.

[Easy Rider]

Originally Posted by 5th_bike

Yes, the resistor is the "load balancer" if you would subject the LEDs to 12V without a resistor, they would blow up.

Two different things. The resistor in series is a current limiting resistor.

What he is referring to applies when you replace your actual turn signals (front and/or back) with LEDs. The flasher unit is current dependent and won't flash right.....unless you get the current back up or get a different kind of flasher. The load balancers are LARGE wattage resistory in parallel with the new LED bulbs. Kind of makes the whole change pointless, IMHO.

Changing only the indicatory lights on the dash does not create that kind of problem.