Automotive batteries can be divided into traditional non maintenance free batteries and maintenance free batteries. Nowadays, automotive batteries on the market are mainly maintenance free batteries.

Its cost is relatively low, and because it will reduce the liquid (electrolyte) in the daily use process, it is necessary to regularly add make-up liquid (distilled water) to its interior to ensure daily use. For the convenience of adding distilled water, there will be six convex liquid replenishing caps on the upper part of the non maintenance free battery, which is also the most obvious difference between the non maintenance free battery and the maintenance free battery in appearance. However, due to the improvement of modern manufacturing technology, non maintenance free batteries generally do not need additional maintenance (adding distilled water) during their service life, and their service life is no different from that of maintenance free batteries. At present, Japanese brands are commonly equipped with non maintenance free batteries.

Because the electrolyte consumption of lead-acid battery is much less than that of traditional lead-acid battery when it is used, and the battery is designed with internal circulation and more airtight, its maintenance free characteristics can be realized. In addition, the maintenance free battery has the advantages of high starting current, low self discharge, and low corrosion to the battery pile head. At present, most models on the market are equipped with maintenance free batteries.