How are the two separate battery systems separated on our GMCs?
You have two separate battery systems in your GMC. First, you have a battery that is just for starting and running the engine, running lights, dash lights, gauges, distributor ignition, etc. Second, you have what we often refer to as you house battery. This is either a single 12 volt. battery or two 6 volt golf cart batteries in series, or sometimes (but not recommended), two 12 volt batteries in parallel. The engine battery is designed for heavy loads for short times and it is charged back up quickly by the alternator. The house battery is designed for less heavy loads for longer times and is often called a “deep discharge” battery. It is designed to be taken down low and then recharged whereas a battery designed for starting an engine will fail after relatively few deep discharges. The engine alternator will charge both sets of batteries. It does this by use of an “electronic switch” called a “battery isolator” (some GMCers now use a “combiner” which does the same function but operat
