isaune wrote: I must admit I was assuming it was simply a case of joining positive to positive to positive and negative to negative to negative with the battery nearest the heater to connect to that and the existing leisure battery to be connected (as now) to the split charge relay?
But from your warning, I am guessing it is not that simple???
You are correct, and yes it is that simple
It's just that one needs to be a bit cautious when dealing with these sort of battery powers
The advice posted after you wrote the above is all good, though as mentioned, that article may be a bit ott in some respects for a camper van. Just make sure the linking wires are capable of handling say 50 amps and are carefully and neatly installed. Don't forget in line fuses on the charging wires and the output wires. Use those HD blade fuses with thick wire "tails" on them. You can pick them up from any decent motor accessory shop. Install them close to the battery(s). You can't have too many fuses ! Those white terminal connectors (like these = HERE) are fine as long as they are of a suitable size and carefully used. Tip = bare the wire end just enough to go 50% into the connector with none visible outside the connector, then fold the bare bit back over the plastic and then insert the wire into the connector with the plastic side facing the screw. This makes a good strong connection and as long as no bits of bare wire can be seen, is very safe.
