The Stovebolt Site Forums The Shop Area The Electrical Bay Adjustable LED dash lights

I'm in my dash for other work and thinking about changing my dash lamping over to LEDs. The clock face on the glove box door is hard to read at night due to bulb placement behind clock face. Knowing that LEDs are not very sensitive to voltage change, output wise, once they turn on, how do you guys get them to change in light intensity. My current thinking is I will have to build a circuit that controls a bank of leds that light as I turn up the voltage at the dash rheostat. Anyone got a schmatic for this sort of thing. Thanks

I don't have any schematic but you might take a variable resistor, and run resistors in order of bank, EG: Bank one connected to XX ohm, then bank two connected to XX+3 ohm, etc. As you would turn up the input voltage (Decreasing resistance from the variable), then it would allow more power to flow through the static resistors (the ones that look like little barrels with the lines), and finally get the LEDs to the threshold. If this sounds like a possible plan you'd want to try, I can go by radioshack and see what I can come up with to help you get such a setup going.

I've always read the LEDs are very sensitive to voltage. All of the LEDs I've seen that fit the small bayonet sockets are dimmer than the incandescent bulbs they replace. I put halogen bulbs sold by Bill Hirsch in my '38.

Tiny is correct, LEDs are voltage sensitive. Most I've worked with "come on" at 9 volts and get brighter till battery voltage is reached. But after about 11 volts you don't see much difference in brightness. As far as being dim compared to incandescent, well if you do the research you can find some really bright units but you need to speak the lingo. I'm going the easy way on this. A rotary switch which as you turn it clockwise will turn on more LEDs. Will see how it goes goes as I had to find and order the parts. Thanks for the invite for help 59 Rolling Iron.

I'd be interested in finding a source for an LED replacement for the #51 and #55 bulbs that's brighter than the incandescent. I've purchased so called replacements from super bright leds on line only to find that while they have the mini bayonet base they don't fit the application space (space provided in the dash) and side by side they are no brighter.

Tiny, what is your application for the #51 and #55 bulbs? I have also run into the size problem with some of these wild looking LED's. Last time was with some wild looking LEDs for my tail lights that were too tall for my buckets with lens attached. Ended up making up an array of white LEDs to fit the buckets. Will be trying to brighten up the instrument cluster after the clock.

Tiny, After pondering about all this last night I was thinking the the #51 and #55's are used in your instrument cluster. If that is true then I can see your problem. Oher than the hi-beam indicator, the rest of your bulbs would need to radiate light in a 360 degree pattern. As you know LEDs radiate light pretty much out the front. I my case, I've turned the LED's 90 degrees so the light fans out across the face of the instrument. This is more than you might want to do as the halgoens have solved your problem. I will look around for a LED that fits the #51 issue and "sprays" light in a 360 degree pattern. If I find it I'll post an update. Thanks

Cool, thanks.