Close up of a car battery sitting inside an engine

About car batteries

The battery stores energy in chemical form that is released on demand as electricity. The energy is used by the vehicle's ignition system to crank the engine, as well as power the lights or other accessories. If your alternator fails, your vehicle can run on the battery alone, at least for a short period of time. Normally, however, as long as your engine is running, the alternator keeps the battery recharged. If you operate any electrical items with the engine off – such as power windows, the audio system or headlights – the battery will slowly drain.
Because automotive batteries contain hydrogen-oxygen gases and sulfuric acid that can cause serious burns, you need to observe some precautions before you handle the battery. The American National Standards Institute recommends wearing safety glasses or goggles and a face shield. Other precautions include never leaning over the battery, working in a well-ventilated area and keeping all ignition sources like cigarettes away from the battery. Now, on to car battery care:

https://mobiloil.com/en/article/car-maintenance/basic-car-maintenance-tips/car-battery-maintenance