The best way to maintain battery health is avoid additional system draws or loads. When running errands, or making trips, try and make them extended, or run a few errands at the same time. Lastly a great investment is a trickle charger for when the car is parked.

The only time the battery is really used to provide energy is during start up or when the car is off, or in the “Accessory” position. Once the car is running, the electrical energy needed is created by the alternator, which flows electricity through the battery, thus keeping it recharged but also stabilizing the alternator output (absorbing voltage spikes, etc.)

When large loads, or current draw components, are installed they can strain the alternator which then prevents the battery for receiving a full charge. Worth mentioning if the additional load doesn’t stress the alternator or demand more current the alternator outputs, it’s probably okay.

Short trips do the same thing. The battery looses energy during startup and if the trip is too short the alternator doesn’t get enough run time, at peak output, to charge the battery back to full state of charge. Do this enough and you slowly deplete the battery charge. You see this commonly with people who don’t drive a lot.

Lastly when these conditions occur, and the battery charge is slowly depleted with each drive, the battery becomes sulfated which prevents the battery for taking a charge. This why people who never, or rarely, drive have to replace their battery every few years.