My factory battery lasted two years and eight months (83,000 miles). I replaced it with a Group 48/H6 X2Power AGM dual-purpose battery by Northstar. I ran 12V from the battery, through a 100-amp circuit breaker, and to the back of the car via 4-gauge wire to a 120-ampere relay on the driver’s side of the subwoofer panel. The relay is triggered by a voltage controlled switch, the APO3. The APO3 allows battery power to feed the rest of the panel so long as its voltage is above 12V, basically any time the car is running, or for about thirty minutes after shutdown. Once the battery voltage falls below a preset threshold (I can set it for 13.05, 12.7, 12.1, or 11.8 volts) for a preset time (0, 5, 10, or 20 minutes), the 120A relay loses its trigger until the car is restarted and has run for a few seconds. The APO3 assures good battery health and no surprises as a result of a dead battery (been there, done that). From the relay, 12V travels to a large fuse block. The large fuse block feeds the subwoofer amplifier, an Icom ID-5100A VHF/UHF digital amateur radio transceiver, a “Super Booster” voltage regulator for the ID-5100A, and a Raspberry Pi3 mini-computer w/DV-Mega (not pictured). There’s a jump-off point that feeds a small fuse block, powers the turn-on leads for the EQL and the subwoofer amplifier. There’s also a feed from the large fuse block that sends 12V back to front of the car via 70-amp circuit breaker to power my trailer lighting and a 400-watt pure sine wave voltage inverter.
More Complex Than Required,