Dual Battery Bank Wiring Diagram

Use the following wiring diagram if you are using the GP-PWM-30-UL to charge two separate battery banks. Connect battery bank 1 to the battery 1 terminals and battery bank 2 to the battery 2 terminals on the back of the solar controller. 

IMPORTANT: Ensure your primary/permanent battery (house bank) is connected to the battery 1 terminals. Connect your secondary battery to battery 2 terminals only. Your permanent battery (battery 1) will receive the full current first. Once battery 1 is fully charged, current will be available to charge battery 2.

 The controller will not work unless there is a battery connected to the battery 1 terminals.

The GP-PWM-30-UL Maximum 37.5A rating is based on a 30-amp total maximum short circuit current rating (Isc) from the solar modules nameplate ratings. The National Electric Code specifies the PV equipment/system rating to be 125% of the maximum Isc from the PV module ratings (1.25 times 30 = 37.5A). E.G. Three modules in parallel with an Isc of 7 amps each equal a total Isc input of 21 amps. When selecting PV modules for use with the GP-PWM-30-UL do not exceed a total nameplate Isc current of 30A. Solar modules list the Isc amps on their nameplate label.
 

IMPORTANT: The fuse or breaker used should be no larger than 50 amps