Lead-acid batteries because of its low manufacturing cost, large capacity, inexpensive and widely used. However, if used improperly, it will be greatly shortened life expectancy. Many factors influence the service life of lead acid battery, and a correct charging method, can effectively prolong the service life of the battery. There are several methods for battery charging:

1. Constant current charging method.

Constant current charging method is used to adjust the output voltage of the device or change the charging and battery series resistance method, maintain the strength of charging current constant charging method, as shown in figure 2. The control method is simple, but because the battery current capability is acceptable as the charging process gradually decline, to the charging period, the charging current for the electrolysis of water, gas, the air outlet is too, therefore, often selecting phase charging method.

2. Two stage charging method.

The method includes two stage charging method and three phase charging method.

1) The two stage method with constant voltage and constant current combined with rapid charging method, First of all, to constant current charging to a predetermined voltage value, and then, to complete the remainder of the constant voltage charging Generally two stages between the transfer voltage is the second phase of the constant voltage.

2) The three stages charging method in charge at the beginning and end of the constant current charging, using constant voltage charging. When the current decays to a predetermined value, by the second phase transition to the third stage This method can be reduced to the minimum volume, but as a fast charging method used, subject to certain restrictions.

3. Constant voltage charging method.

Charging power supply voltage in charging time constant value, with the battery terminal voltage rises gradually, gradually reduce the current. With the constant current charging method is compared, the charging process is close to the optimum charging curve.

The charging method of electrolytic water rarely, avoiding the battery overcharge. But in the initial charging current is too large, the service life of the storage battery to cause very big effect, and easy to make the battery plate bending, causing the battery scrap.

In view of the shortcomings of constant voltage charging, rarely used, only in low voltage and large current charging power supply by. For example, during the running process of the automobile, the battery is charged with constant voltage method.