I looking for some clarification on the batteries and charging system on my recently purchased 1989 300WE. The owner's manual has a bilge layout diagram which correctly shows 3 batteries in a row between the engines. I'm assuming that there are 2 engine batteries and 1 house battery. There's also a diagram of the emergency start system, which I have, but it only shows 2 batteries, each having an on/off battery switch. I have 2 battery switches, a 1/2/1+2/off and an on/off. I'm thinking that the 1/2/1+2/off is for the 2 engine batteries and the on/off is for the house battery. There's a 120VAC powered Chargemaster 12/25-3 charger with 3 outputs connected to the 3 batteries. The manual also has small section on the crossover charging system, but it only mentions 2 batteries. Reading between the lines, it sounds like either engine alternator can charge either engine battery. Does that mean that the house battery is only charged when plugged in at the dock? I need to spend some time tracing wires and get this sketched up as I haven't been able to locate a wiring diagram for the boat.