Thread: trailer running car bateries flat when stopped

Hi fendie999, to do it so that the operation is automatic and does not require the trailer to be disconnected, is to fit a dual battery charge controller under the bonnet.

Cheers.

I fitted a relay which is switched off the aux position in mine. When the key is off, the house battery in the caravan is isolated from the car.

Trev.

<span style="color:blue">and i think its the blue wire on the trailer plug....</span>

Originally posted by fendie999
hi my mate was telling me his trailer is running his car bateries flat when stopped i,s there a easy way to prevent this with out having to unplug the van. cheers

Sounds like he has the battery in the trailer wired directly to the battery in the car and not through the trailer plug which is controlled by the ignition isolating the trailer battery, or he has a short somewhere.

If he doesn't go the dual batt system way, wire the trailer battery through the ignition so when the ignition's off, so is power to the trailer.

<span style="color:blue">mine has a constant feed to the trailer plug irrespective of the ignition switch.....

i think it might be standard....
all you do if you dont need the power to the trailer is cut the wire....

or run a separate wire via a relay to the trailer which can either be operated manually or via the ignition switch......</span>

This is a bit of a repeat of some of the other answers.
It is my understanding that most trailer plugs can be wired to have a hot wire to the trailer, I did this to keep the 12V fridge running while traveling. The auto electrician who performed the wiring installed a lighted switch on the transmission tunnel that is illuminated when on, so if you are going to be parked for any lenght of time you can switch it off.

thanks guys . ill send it onto him im shore we can fix with a few beers