1+2 paralleling would not be good long term for the charging solution unless your batteries are similar (i.e. Switch set to '1+2' allows both batts to be charged and also to be used for starter power (paralleling).Ī. You can just run the alternator wire to the common feed and it'll charge whichever bank its on, 1 or 2 or both. Switch set to '2' isolates batt 1 and batt 2 will handle starting duties and be charged. With the switch set to '1', Batt 1 starts and gets charged, Batt 2 is isolated. You can and should wire both the alternator charging wire (100 amp in my case) and the starter wire to the 'C' lug. If we agree A is correct, then my question actually turns to the downstream wiring of the alternator, starter and/or winch to the 'C' or common lug. So, let's say batts 1 and 2 are both 900amp batteries fully charged, the '1+2' position on the selector switch gets you 12V at 1800 amp/hrs (parallel wiring increases capacity but not voltage)ī. If you have Batt 1 to Lug 1 and Batt 2 to lug 2, this is effectively a parallel wiring setup going to the starter (leave the winch out of it for the moment). So, I'm thinking the proper way to wire it would be:Ī. If you look at the back view, you see the lugs marked 1, 2 and Common (C). I'm assuming those amperage ratings above are at 48V, which I think means they would be much higher at 12.5V (like by almost a factor of 4.) Right or wrong?Ģ. If your goal is to wire in 2 batteries in the 'reserve' configuration, meaning one battery is the starter and the other is a deep cycle that also will have a load (winch) and have the charging circuit work properly, this will do the job but it is not as flexible as some of the other methods.ġ.

Winch battery isolator wiring diagram