VW Electrics Stereo feed from both batteries

JamesSC: Basically it allows the stereo to run from both battery's...

...so if you have an isolator switch on your leisure battery the stereo will still work whilst driving, plus allows all charge thats going to the leisure battery to actually go into it rather than powering the stereo at the same time.

Had this set up on mine for a good while now, and when the ignition is switched on the relay latches to the main battery when off it latches to the leisure battery, if the relay was to fail it will fail latched on the leisure battery side.