sourcing LEDs

[yaknowthatguy]

Okay gang, I've searched the internet high and low until I think I found the end of it, and am still not having any luck finding the right LED.

I'm looking for something about 3/4" diameter, threaded like a bulkhead fitting, in amber. I plan to tie it into the front turn signals eventually, ideally it'll be bright enough to fit the purpose.

I've found some bulkhead fitting LEDs...just not in 24v. Putting a monster resistor on it doesn't sound appealing, I'd REALLY like to find it in native voltage for our trucks.

if anyone has suggestions....I would really appreciate it. thanks!

[spandit]

Can you post the link to the 12V ones you've found so we know exactly what you're after?

I don't think you'd need a huge resistor as LEDs are such low current. I get confused with electrics, but a 3W LED should draw 1/4 AMP (0.25A) on 12V. I think to run this off 24V you'd need a 48Ohm resistor. Get someone to check my calculations, mind...

Why do you want to convert to LEDs? Are you getting through conventional bulbs that quick?

[krick3tt]

http://www.superbrightleds.com/cgi-bin/store/index.cgi

http://www.24voltproducts.com/

[Jimm391730]

ALL LEDs are between 1.8 volts (red) and 4 volts (white). They still need some way to control the current through them to no more than their rated value; either by way of a constant current source or a simple resistor. Obviously for a certain current, a 4 volt white LED wastes double the power in the resistor when powered by 12V, or 5 times the power when powered by 24V -- but if the power is small, then it is no big deal.

Better to use a string of LEDs that gets you closer to your drive voltage, so you get more illumination power and less waste in the resistor. For my custom LED tailights I used nine red LEDs in series (requires about 16 volts) and I waste the rest of the ~28 volts (when the truck is running) in the resistor. When the truck is not running, the reduction in voltage does make the current through the LEDs drop, too, but the brightness is NOT linear with current; in fact, you have to really do an A to B comparison to see the difference. I could have put up to about 12 LEDs in series but 9 was a compromise between the brightness difference between 28V running an perhaps 22V if the batteries are almost dead.

Since most LEDs are not as bright a light emitter as most incandesant bulbs, using multiple LEDs in series both increase the light output and increase the efficency. Yes, there are "efficient" constant current LED drivers but they are fairly complex and expensive to buy unless you feel qualified to roll your own.

[pcolette]

Is this anything like what you're looking for?

http://www.mcmaster.com/#7380k3/=bgksvu

I used these to replace the indicator lights on the hydraulic locker panel.

[Winter Beater]

I recently changed the Pinz to LED's. You like don't need more than a 1/4 watt for the conversion to 12V. The 'monster' resister will only be on the turn signals to fool the flasher into thinking there is still a 40 watt bulb in the circuit. For turn signals I stripped the guts from the stock housing and inserted 2 LED packs; 1 for parking lights the other for signal lights - looks stock but LEDs should outlast the truck.

I think the formula I used was R= [V(pinz, 24) - V (LED) ] / LED current (in Amps not mA)

Some LEDS are 40 mA others 90 mA, you can modify the resister to get the proper voltage drop. These 1/4 watt versions are $2 for 5.

[yaknowthatguy]

sorry for the delay guys - here's the website I was looking at: http://www.genright.com/category.aspx?categoryID=60

The products are the LED 3/4" round markers. I think for the application I want, these would be ideal. now to see if I can find them in a 24v version.... I'm all ears if someone has ideas.

thank you!