FWIW: Here is a 3.3GPM on demand pump that is 115v AC. That way there is no need in figuring out a 12v supply with enough amperage: SHURflo Industrial Pump — 198 GPH, 115 Volt, 1/2in., Model# 2088-594-154 | Utility Pumps| Northern Tool + Equipment
Hope the link is okay since it's not a...