Quote:
Originally Posted by achang1
oh i forget, i dont know if jeeps have mechanical or electronic flasher relays, but would an electronic relay automatically fix the flash rate in cars?
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Yes, you can get LED-specific flashers. Which you will need if you replace both conventional brake lights with LEDs. I have a cheap one I didn't end up using if you're interested.
Or alternatively you can solder in a 3 ohm 20 watt resistor between the B+ and common negative on both of the LED brake lights and that will solve the issue.
LEDs offer so little electrical resistance compared to incandescent bulbs that the coil in the flasher relay trips much faster. So adding the resistor fixes that issue.
Quote:
Originally Posted by achang1
1. oh also, i hear you cant judge how bright the LED is simply by its MCD? I'd probably prefer wide angle leds with as bright as possible?
2. and if its a multi coloured tail light, should i get red for the red part, and amber for the amber part, or should i just get all white?
3. edit: Keld's DIY page- LED found the dual intensity method.
i dont know how to read schematics so can someone explain how they did it? thanks. |
1. You can, but the LED will only deliver it's rated output at the specified voltages. 3,000mcd LEDs are fairly bright, but 6,000mcd LEDs are EXTREMELY bright (6,000mcd = 6 lumens). LEDs are just very directional, and you'll need to use a bunch of them.
2. Depends on how heavily tinted the lens is. 6,000mcd White LEDs for all three should work fine. Most yellow/amber LEDs are too dim to really work anyways.
3. The L+ is the supplied 12v+ power for the running brake light. The B+ is the supplied 12v+ power for the activated brake light.
L+ powers the LEDs through a set of resistors that end up delivering about 80% of the rated power to the LEDs so that they're not at full intensity.
The B+ delivers the remaining amount of voltage (since the L+ is always on) to bring the LEDs to their full intensity.
LED symbol
The wiring for brake lights have a common negative. So the cathode of the sets of 4 LEDs are wired to that.
That schematic should work fine for any 2.2 volt 25mA LEDs. You can increase or decrease the array size by adding or removing sets of 4 LEDs from it.
This circuit is a bit simpler:
http://www.sca40.com/led/