AlexJet

As I'm about to finish all mechanical work on building an expedition trailer and start wiring portion of it, I come up with an idea of using flood light as my back-up light on the trailer. Those lights are rigid enough to withstand the abuse trailer will have and give an option of lighting up the terrain behicnd the trailer when I back it up.
Regarding all this I have a question Toyota can't answer me. I do drive 2005 4Runner, but this may be answered by other members driving other vehicles as well. My OEM 7-way connector has back-up light wire as well as 12v power wire. Would back-up wire in my original trailer harness hold up for 2 55W bulbs in back-up lights? How much would that wire hold? How much is 12v power wire designed to hold? I think I saw only 1 fuse for trailer harnes in my fuse block if I'm not mistaken as it was a long time ago when I was checking this out.
ANy thoughts, ideas and opinions will be very much appreciated as I'm about to start wire it up within a day or two.

Elton

you got a pic of your trailer maybe you could add in a extra set of led backup lights ?

firemaniac

Are you running 12 volt power on the trailer? If so use the back up wire from the truck to trigger a relay on the trailer to activate the lights. This will also allow you to add a switch on the trailer to activate the lights when disconnected from the truck for working around camp at night.

AlexJet

No battery in the trailer for now.

ID96_4Runner

Even on full size trucks meant for pulling travel trailers, the 12V wire is only meant for recharging the trailer battery. So neither the 12V wire, nor the back up wires are going to be big enough to handle 55 watt lamps.

The idea of using decent lamps for your back up light is fantastic. But I agree with Elton, that LEDs are your best option for the limited amount of current you can push through those wires.

I also like firemanic's idea of battery on board to power the flood lights. I've seen someone else do that with his car hauler and it was sure handy. Then you can use the 12V wire to recharge the battery like it's meant for.

AlexJet

This is something I will consider in the future. But for this moment I don't have spare battery, especially deep cycle in my garage to share on the trailer.
I think, I'll just go with LED bulbs and power them withback-up wire. LED draws very little power compare to Halogen, so this should be fine for that wire.

AlexJet

I found 12W and 18W LEDs for back-up lights. Would 18W be fine with back-up circuit, 18x2=32W, or should I stick with 12W which is 12x2=24W?

firemaniac

I have to disagree with the charging wire being to small, that wire in my experience is usually a heavier gauge to be able to carry the amps to recharge a battery.

You could still build a small electrical junction box area and put a relay on the trailer to power the lights from the charging wire that is triggered by the back up wire. If/when you decide to use a battery on the trailer it would be simple to run the charge wire to the battery and the relay off of the battery, just leave a loop or two of slack in the wire to make the addition later if you choose to, you won't have to completely change all of the wiring to add a battery