1. Can't charge, can't charge on.
2. The battery does not store electricity and will soon run out of electricity.
3. The battery cannot be used.
A bad battery will be damaged more quickly, and it will be damaged with other good batteries. If the battery is broken, the capacity will decrease and the internal resistance will increase. The more intuitive change is that the charging and discharging phases will swell, and the bad battery will be first. It is fully charged or discharged first, because the charger or controller only recognizes the voltage regulation, but because the voltage of other good batteries has not yet arrived, the battery pack will be required to continue working, which will cause the voltage of the bad battery to be charged. Higher or lower, this kind of operation will accelerate battery damage. The final result is that the broken battery breaks more thoroughly, and the good battery is also damaged.
How to judge whether the electric vehicle battery is damaged?
1. Use a tester to test the discharge of the battery. The two most important technical indicators of lead-acid batteries for electric vehicles are power storage and internal resistance. The storage capacity must be tested by the instrument for a 10a current discharge test and judged according to the discharge time. A new 20ah battery must have a discharge time of more than 120 minutes before it can leave the factory. The internal resistance should be tested by an internal resistance meter. When the voltage is 13.2v, the internal resistance is about 10 milliohms, which is a good battery.
2. Speed up the test and observe the drop of the pointer. The easiest way is to test by yourself, first replace the new battery, and then accelerate. During the acceleration, if the pointer drops less than half a block, then it is a new battery. And if the pointer drops more than one bar, or even two bars, then it is likely to be a refurbished battery. And when the pointer drops more than three bars, then the battery is a low-quality battery that is close to being scrapped. Battery maintenance method: prevent the battery from overcharging. The overcharge of the battery generates a large amount of gas to flush the electrode plate, which accelerates the shedding of active material on the electrode plate and shortens the battery life. Overcharge of the battery accelerates the loss of water, which causes the electrolyte to dry up and the temperature of the battery rises, causing thermal runaway, expansion of the electrode plate, and deformation of the shell. Prevent the battery from over-discharging. Pay attention to skills when using the battery car, which can also extend the battery life. Long-term deep discharge will cause the battery plate to soften and shorten the service life. Prevent high current discharge. Try to use your feet for assistance when starting, uphill and driving against the wind.
3. Prevent long-term discharge, and don't drive when the battery is completely discharged. Charge it when the battery is reduced by 1/2. Prevent the battery from losing power. For batteries that have been left unused for a long time, they should be fully charged once a month. Generally, it is better to continue floating charging for 5 hours after the charger's red light turns to green light.