An A-B switch can be bought at any auto parts store. Switched to the left it connects circuit A, to the right it connects circuit B and in the middle is off for both, and there is no way it can connect both A and B at the same time, so you know you only charge one battery bank at a time.
Just get a high amp switch.
Put the switch on the positive wire out of the charge controller, and then on the other side of the switch you will have two wires go to the A and the B (camper or trolling motor batt). The negative wires can all be connected together.
Connect the trolling motor before switching.
The more solar panels you have the faster the charge will be.
If you connect the trolling batts to the camper batts then the initial charge will be faster as the troll batts will pull charge off the topped-off camper batts, then when they equalize it will be faster to have only the troll batts connected, but then the problem is your camper batts will be very low.
