Dual Battery System Setup

[Doug1]

Originally Posted by ilikeike

I put together a couple of multi battery wakeboard boat stereo systems. Keeping it simple I just used a starter solenoid.
Key on engine running solenoid closed all batteries connected and charging.
Key off or acc. Solenoid open, batteries isolated.

Simple and works, for years.

I would but my research led me to a few articles that point out that the AGM batteries require a DC-DC isolator to charge to 100%. Apparently they otherwise only charge to 80% with an basic switch. Same thing with 120v chargers. You should use one designed for AGM batteries verses wet batteries.