- Wet cell batteries require periodic watering. These are the traditional type of car battery, which uses liquid electrolytes to conduct electricity. As the battery discharges, water is lost through evaporation and electrolysis. This can lead to damage to the battery plates if the electrolyte level drops too low, so it's important to check the water level regularly. Add distilled or deionized water only, as ordinary tap water contains minerals that can damage the battery.
- Maintenance-free batteries do not require adding water. These are a newer type of car battery that uses a sealed case to prevent water from evaporating. They are also less prone to electrolysis than wet cell batteries, so the electrolyte level does not need to be checked as often. However, if the battery is damaged or overcharged, it can still lose water, so it's important to inspect it periodically for any leaks.
- Gel batteries are a type of maintenance-free battery that uses a gelled electrolyte instead of liquid. They are even less prone to water loss than sealed AGM batteries, so they do not typically need to be watered. However, it's still important to inspect them periodically for any leaks or damage.
