I have just had a Redarc BCDC1225 installed with a RED anderson plug for solar panel input (reminds me that this is for unregulated solar input only) and a 100 ah aux battery under the bonnet of a 2011 Pajero. I also have an anderson plug at the rear of the car, connected to the aux battery. I intend to put a battery on the van and connect it via this anderson plug. I understand the 2 aux batteries should be the same type/capacity etc., so I assume this will allow the van battery to charge from the BCDC1225 too. I also understand that the van battery may take longer to charge due to some voltage drop, correct so far?
My next problem is getting power to my Waeco 60Lt fridge in the rear of the car. Would it be a problem to pick up power from the lead running to the anderson plug and insert a 12v socket in the rear cargo area? Would this compromise the van battery recharging? I have run out of room to get wiring into the cabin through the firewall so am looking for an alternative. The lead to the anderson plug is around 7mm or 8mm.