An electric vehicle battery is the power source of the vehicle and is a consumable. How can you tell when it has reached the end of its life? Let us explain.

1. If the battery capacity is below 60% and does not improve noticeably after maintenance, it can basically be considered worn out.

Reason: during use, once the capacity of a lead-acid battery drops to about 60%, its performance declines sharply, the internal parts have mostly deteriorated severely, capacity loss speeds up gradually, and it soon loses the ability to charge and discharge completely.

2. The battery charges fully in a very short time but runs out of power after only a few kilometers.

Reason: the battery is aging, or one cell in the pack has failed, so the whole pack stores little power and charges easily; naturally, the driving range is also very short.

3. The outer casing of the battery becomes very hot during charging or use.

Reason: the heat is caused by severe shedding of the active material on the plates, which increases internal resistance and heat generation. If you open the safety valve of the battery for inspection at this point, you will see the electrolyte has turned black, and when the failure is severe it cannot be repaired. At this stage the battery self-discharges quickly, and sometimes it loses its charge soon after being fully charged.

4. The battery is swollen, or its casing is deformed or cracked.

Long-term high-current charging or overcharging causes the battery to swell, and in some swollen batteries the plastic casing has been squeezed and cracked; such a battery can no longer be brought back to life by repair alone.

Therefore, electric vehicle users should pay attention to battery maintenance in daily use; when a problem appears, have it checked at a professional repair shop, and when the battery must be replaced, be sure to choose a good one.