LED Instrument Illumination Options

[GeorgeRud]

Has anyone converted their instrument panel illumination lights to LEDs yet? They are being sold as upgrades and are supposed to make the instruments brighter (good for these older eyes). I know the 2 watt bulbs can be replaced with 4 watt bulbs, but I was warned by North Hollywood Speedometer not to do it as the extra heat generated will eventually fry the innards of your instrument. I like the idea of brighter instruments however.

[lapuwali]

I'll bet that NH Speedo setup has quite a few LEDs in there. A lot more than 2, anyway. LEDs don't put out a lot of light compared to incandescents, and they only put out light in a narrow beam, not spherically. They use so little power and emit so little heat, however, that you can use a dozen of them in place of one bulb and end up with more light for less power. You need to rig up a little board with them mounted so they point in several directions to get a good spread of light.

LEDs also can't be dimmed using the normal means of just reducing the voltage, so you're dash light dimmer won't work. LEDs are either on or off. "Dimming" them involves flashing them fast enough you can't quite see the flashing. The duty cycle of the flashing will determine how bright it is. This doesn't take much circuitry to accomplish, but it's more than a simple rheostat and a bulb.

The eye does not respond well to blue light, and things lit with that appear fuzzy to just about everyone. Green is a much better color to light something with, but green LEDs are quite a bit dimmer than blue leds. If you use an array of blue, red, and green LEDs, you end up with nearly white light (tends to be blue-shifted, since the blue LEDs are so bright). Amber LEDs also work pretty well for lighting.