Charging a trailer battery

[StreetDragster]

Hi All,

I hope someone can help me, as i think i'm missing something.

I have a car trailer which has an electric winch, currently powered by a 12v jump pack. I want to change this to an onboard battery, charged by the car when its engine is running.

The car is a Range Rover Sport, 2008 with a TDV8 engine and a 13 pin trailer socket. I have earth on pin 11, and +12v on pin 10 when the engine is running. I believe this is the cabling i would connect the battery to for charging.

Is that it? Do i simply connect pin 11 to the trailer battery earth, pin 10 to the trailer battery positive?

No need for a split charge relay?
Do i need something to prevent voltage from the trailer battery some how getting into the cars circuits when the engine isn't running? If so, what do i need?

Thanks

Matt

[Gavin0478]

The split charge relay etc will be fitted to the car and not in whatever is connected so if you have a feed from pin 10 its fitted (unlike in Audi's)
Pin 10 is classed as the fridge feed or ignition feed and pin 11 is the dedicated earth for pin 10.

You should be fine to connect the battery to these for it to charge but as always the fitting of a fuse is advisable.
Reverse feed or current should not be possible as long as the tow vehicle has the ignition switched off thus opening the feed relay when you use the winch or by leaving the engine running so it is being supplied by the car.

[StreetDragster]

Perfect, thanks

Matt