A battery isolator typically is used in situations where multiple batteries are required, and its primary purpose is to ensure that the failure of a single battery will not incapacitate an entire electrical system. Some sort of battery isolator is required if the alternator is going to be used to charge more than one battery.Ī battery isolator is a one-way electrical device that allows an electrical current to flow in one direction but not the other. These batteries are typically deep cycle batteries that prefer to be partially discharged and recharged on a regular basis. The batteries used to provide power operation of DC and AC appliances in a work truck, recreational vehicle, or boat are called the house batteries. If this battery is drained down because the car won't start or the lights were left on, the battery life decreases rapidly and will probably remain dead the next time it is drained down. Automotive type batteries do not like to be discharged to a low level.

This battery relies on the alternator to keep it charged up for the next cranking cycle. The vehicle (chassis) battery is typically an automotive type of battery that provides high cranking amps to start the engine. Work trucks, boats, recreational vehicles, long haul trucks and fleet vehicles all have a battery isolator if the alternator is being used to charge both the house and vehicle batteries. What type of battery isolator should be installed?

Battery isolator wiring