How To Wire 4 Batteries In Parallel. It will maximize the lifespan of all your batteries as they will be charged and discharged evenly. This wire connects back to the POS terminal of battery number two in the left bank.

Parallel coupling involves connecting the plus poles of multiple batteries to each other and the same with the minus poles. This method of charging batteries in parallel will result in each battery drawing the same amount of current from the charger. The plus of the first battery and the minus of the last battery are then connected to the system.
The more preferred ways to equalize load and charge is seen in these pics.
The four 12 volts AGM batteries are from VMAXTa. Wiring Batteries in SeriesParallel Combination. Batteries C and D are in parallel. The right battery bank has an extra red wire on the POS terminal of battery number four.

