If you are running a few extra electrical Items in your camper then we recommend the fitting of one of our leisure battery and intelligent split relay systems.
We use the smart Durite 140amp relays these will automatically switch once a high enough voltage is being produced at the vans start battery and the cuts the connection if the voltage drops. This prevents the larger capacity leisure battery from draining the power of the vans starting battery.
We use correct size cable and fuses to cope with the high load that can be placed on the system. Beware of lessor sized cables!!