It's wired wrong in that the power to the amps is tapped off the perko switch, tap the power directly from the battery + terminal directly to the amps (using a breaker or fuse as close to the battery as possible).
If Perko the switch is in position one, the only battery getting the alternators charge is battery 1. (When the engine is running) When switched to battery 2, only battery 2 is getting the alternators charge. Newer perko switches also have a position labeled "both" so it combines the charge to both batteries. There are other battery combiners out there, like the Yandina 100 or Hellroaring that do this switching automatically.