Can Different Group Batteries Be Wired in Parallel

Question:

RV battery parallel Wanting to add a extra battery to RV.. does it need to be the same group battery?

asked by: Matt

Expert Reply:

When running batteries in parallel (or series) you will want them to be the same group, type, and ideally age. Connecting dissimilar batteries can lead to overcharging or undercharging on one of the units since they will have slightly different charging/discharging characteristics and may also shorten their lifespans.

When wiring two batteries in parallel you will connect the positive terminals to each other and the negative terminals to each other (see attached image). Wiring them in this manner will maintain the same output voltage but increase the capacity.

expert reply by: Chris R