I did "A". I think that is perfectly fine. Only important thing is that the Pos lead come of one pair and the Neg lead comes of the other pair, so both strings get equally utilized. This is what you have drawn. On my boat I run 6 each 6 volt batteries (3 strings) in same layout. Three strings in parallel appears to be the recommended limit.
2015 Transit Van Silver 3.7L 148 HR. DIY Camper.
Last edited by jethaden; 03-28-2016 at 09:50:PM.