The maintenance-free battery is made of lead-calcium alloy. Because the battery uses a lead-calcium alloy as the grid, the amount of water decomposition produced during charging is low, and the amount of water evaporation is also low. In addition, the sealed structure of the outer shell also releases sulfuric acid gas. Few, so compared with traditional batteries, it has the advantages of no need to add any liquid, less corrosion to terminal posts, wires and body, strong resistance to overcharge, large starting current, long power storage time, etc. In recent years, it has It is very popular in China.

　　The rated voltage of a single lead-acid battery is 2V, the number of charging and discharging is between 200-300, and the rated service life is 3 years. The lead-acid battery used in the car is 12V, which means that the battery used in the car is 6 single cells connected in series to form a battery pack, reaching the rated 12V voltage.

　　The label of auto batteries used in China is generally similar to "6-QAW-54a".

　　1). Among them, 6 meter batteries use 6 cells, Q stands for auto batteries, M stands for motorcycle batteries, D stands for electric vehicle batteries, F stands for valve-regulated batteries, JC stands for marine batteries, and HK stands for aviation batteries. .

　　2). A and W indicate the type of battery, A indicates what type of battery, W indicates a maintenance-free battery, if not marked, it indicates an ordinary battery.

　　3).54 indicates that the rated capacity of the battery is 54Ah.

　　4) . The subscript a represents the first improvement to the original product, if it is b, it represents the second improved version, and so on. In addition, some batteries will also mark the maximum current in the auxiliary brackets. Generally speaking, the starting current of the car needs to be more than 250A, so the rated current of the replaced battery must be greater than this value, otherwise the current will not be enough to start the car.