Battery works in the "barren liquor" state, and its electrolyte is fully stored in the electrodes and porous membrane. Once the battery becomes dry, its capacity will decline. When the lost water is up to 3.5ml/AH, the battery capacity will be reduced to 75% of its initial capacity or even less, and when the lost water is up to 25%, the battery’s life will be terminated.

Some effective ways to prevent batteries from dehydration are: control the battery temperature, the charge current and charge voltage; adopt integral seat structure and choose the reasonable open and close valve pressure; use non-antimony grid alloy technology to reduce hydrogen evolution over-potential; improve reaction efficiency and so on.2. Deformation of the battery jar

Once the battery jar is deformed, the polar plates will become loose, and the electrolyte will not be made full use of, thus the battery’s internal resistance will increase and the discharge capacity will decrease.

3. Battery liquid leakage

If there is acid near the battery poles, the connector will be corroded, or the contact resistance of the pole and the connector will be increased, which can also affect other devices of the power supply system.

4. Battery capacity insufficient

Due to the poor quality of a battery, although its initial design rated capacity can be reached, it will soon declined significantly, and drop to below 80% of the rated value not till the specified usage period.

5. Poor uniformity of floating charge voltage of the battery

Normally, the difference between a single battery’s floating charge voltage and the average value of the whole set of batteries is no more than 50mV. The main reason for the poor uniformity of floating charge voltage of the battery is the production process problem.

6. Heat runaway

Improper use or maintenance of the battery will result in a critical state during the constant-voltage charging of the battery. At the time, the battery’s charge current and temperature will react to each other and increase each other accumulatively, which will cause the deformation of the battery jar and shorten the battery life, or even affect the security of the whole power system.

7. Exhaust valve failure

When the exhaust valve fails, its opening pressure will change. If the pressure increases, it will cause the deformation of the battery jar, otherwise it will increase the lost water. If left uncorrected, it will adversely affect the uniformity of the battery set.