Thread: Discovery 3 LED trailer lights

50% duty will produce 50% of the heat but will take more than twice as long to heat up because the resistors will be dissipating heat even when there's no current, ie off.

My D4 needs 2 stop light "globes" and 2 blinker "globes" to reliably make the trailer blinker indicator work and cancel the reversing sensors.

Grahame the stop lights you mentioned do you mean the red tail lights that come on when you turn on the headlights or the lights that come on when stand on the brakes?

I was gonna put in some 21W globes under the bumper but if the heat of the resistors arnt too bad I might go with that. Much easier to splice them in than to make holders for lights etc.

Cheers
Mike

Brake lights.

I do not see why they should get hot with the pulsing as it is not on long enough to turn on an incandescent light. Should only have current when the blinkers are on, and they are not on continuously.

My thought is to purchase an aluminium die cast case form Jaycar and mout the load resistors to that as a heat sink. I the heat is not much then put a switch to disable the Led option, 2 pole single throw between the load resistors and negative to disable the LR when not towing. This could then be permanently mounted in the space behind the left tail light. assembly.

I have a spare plug and the resistors here, so might make up a test rig to see how much heat is generated.

Just a thought what about a couple of nrake globes?

I'm just gonna order a new set of incandescent indicator and brakes lights, it's getting too fiddly.

Thanks for the input.

Cheers
Mike

OK after trolling through this thread trying to figure out what is required (for my D3) I think I have it.

1. 1 x 6 ohm 25watt or greater on each indicator circuit
2. 2 x 6 ohm 25 watt or greater (or 1 x 3 ohm 50w) in parallel on the brake circuit.
3. Relay on each of those circuits as per the diagram in post 16. This prevents the leds lighting from the pulses.

I intend to mount these in an alloy box in my trailer.

Originally Posted by Geedublya

OK after trolling through this thread trying to figure out what is required (for my D3) I think I have it.

1. 1 x 6 ohm 25 watt or greater on each indicator circuit
2. 2 x 6 ohm 25 watt or greater (or 1 x 3 ohm 50 watt) in parallel on the brake circuit.
3. Relay on each of those circuits as per the diagram in post 16. This prevents the LEDs lighting from the pulses.

I intend to mount these in an alloy box in my trailer.

The link below is a list of materials that I used to construct a LED box for my LR3. Yes, North American trailer lighting is a different from Australia but I think our tail light assemblies are the same - that is the signal light bulbs are separate from the brake light bulbs.

I used a pair of 6 ohm x 50 watt load resistors, one for each signal light wire, but none on the brake light conductor.

The relays are in the signal light circuit as the pulses come down the signal light wires, not the brake wire. The little green trailer symbol that flashes when the signal lights do and disable the backup sensors etc, ignore the brake light circuit and filaments. As such, I do not think you would need load resistors across LED brake light filaments. In my case, I did not.

I did use 6 ohm x 50 watt load resistors but only because they are more heavy duty and do not cost much more. I might add that the bright filament in a P21/5W bulb absorbs about 25 watts of power at 13.5 volts and uses about 1.86 amps of current so the 25 watt load resistors will duplicate the signal lights OK.

This is the link to the bill of materials.

http://www.disco3.co.uk/gallery/albu...er_for_LR3.doc

At the bottom of this link are three files re the LED box that I made up based on the wiring diagram in this thread.

DISCO3.CO.UK Photo Gallery - NAS Trailer Socket Pin ID and Wire Colours