Same lights for backup and flood?

[Dougeye]

For better visibility and safety at night, I'm going to add two LED flood lights to the top of the rear of our horse trailer, powered from the trailer battery and with a nearby switch. It would be nice if these lights also came on when backing up. So the lights would have to be wired to both the auxiliary and the backup circuits. So far so good, but I'm thinking I would want to add a couple of diodes, just before the wires from the two circuits come together. Would this work?

 

[Topzide]

Diode would be needed to keep from back feeding the reverse lights. You could wire switch from trailer battery then use a heavier diode current wise than light draw coming from reverse light trigger which I would use a relay. Of course, put a fuse in there just in case. Great project!

 

[i7win7]

How about a relay. Two wires from light, one goes to switch, other to relay. Wire from switch to +12. Wire from relay to +12
Then the other 2 relay wires are ground and backup light power.

Is the trailer battery used for emergency trailer brakes? Is so, maybe a larger battery. If not, wiring in parallel should allow tow vehicle to charge batteries.

 

[Dougeye]

How about a relay. Two wires from light, one goes to switch, other to relay. Wire from switch to +12. Wire from relay to +12
Then the other 2 relay wires are ground and backup light power.

Is the trailer battery used for emergency trailer brakes? Is so, maybe a larger battery. If not, wiring in parallel should allow tow vehicle to charge batteries.

Thanks, I'm liking this idea, but I can't figure out the specific wiring of the relay... could you explain it a bit more? Which side of the relay gets which wires?

As for the trailer battery, it's one of those little sealed units but I'll replace it with a deep cycle battery, and yes, with charging from the tow vehicle and a battery minder when it's parked.

 

[Al 2]

Not exactly what you were asking for but just a suggestion for others who may want to add another set of back up lights , side lights, flood lights or whatever on a separate switch. For $20 or so, you can buy a small remote unit that you control with a key fob. Just power this box from an existing power source, ie your tail light circuit, and use the fob. When I mount my extra back up lights I'm going to add a small LED light on my trailer facing forward to let me know when the back up lights are on.

Something like this.
Relay Switch DC 12V Wireless RF Remote Control Switch 433Mhz One 1-Channel with Two Transmitters: Amazon.ca: Tools & Home Improvement

Al

 

[Topzide]

Go to Car Alarm, Car Stereo, Mobile Video, and Cruise Control Info for Installers.
Great reference for wiring relays and the difference between different types.

 

[Diggin It]

Wire the lamps to the wiper of an SPDT relay. Wire a switch to the NC contact of the relay. Wire the backup light circuit to the coil and NO contact of the relay.


Normal Operation (NOT In reverse).

Relay de-energized. Switch turned on, power flows through switch and NC relay contact to lamp.


BackUp Operation (in Reverse)

Relay energized by the backup circuit, pulling the wiper to close the NO contact, allowing power to flow to the lamps.

 

[i7win7]

post 7 will not work for you, you want "extra" reverse lights - reason for relay. You want manual on/off control of "extra" lights.
hope this video and my comments help.

Relay Wiring Diagram - Bing video

terminal 86 is wired to backup light.
run extra wires from 30 and 87 for your toggle switch

 

[Diggin It]

post 7 will not work for you, you want "extra" reverse lights - reason for relay. You want manual on/off control of "extra" lights.

Which is what it provides.

 

[cmyoung2]

Might be easier just to add 4 lights, two for backup and 2 for work lights. They are not very expensive. Most don't realize that the purple wire in the truck wiring harness is for backup lights. Have them on my bigger trailers, wonderful at night.