Refurbishing or repairing electric vehicle batteries is a very professional occupation, and it is necessary to master the internal composition and principle of batteries. Not all batteries are worth renovating. Generally speaking, if the battery life can be extended by changing the liquid or charging cycle, they can be refurbished. Others, such as those without voltage and current, are unnecessary.

When the appearance of the battery is not damaged or expanded, and there are no signs of short circuit or open circuit, the following methods can be taken to try to repair the battery:

1. Depolarize and charge the battery with positive and negative pulses, and then discharge it completely. Cycle three times. If the capacity shows signs of recovery, cycle it several times to achieve better repair effect.

2. Add water to repair. When adding water, deionized water or purified water must be added. Do not add tap water, which will cause the problem of large self-discharge of the battery. The specific method is as follows:

1) completely discharge the battery first, because the acid density in the battery after discharge is basically below 1. 1g/mL;

2) Take out the cover, then take down the safety valve and keep it properly, so as not to dirty the safety valve for standby;

3) add water. Generally, the amount of water added to one cell of 12AH battery is 8 ~ 10g, and that to one cell of 20AH battery is about15g.

4) Let it stand for about an hour, and then install the safety valve and cover;

5) Charging, fully discharging after charging, and so on for three times.