1. Battery imbalance --------- One or more batteries reach the overcharge protection voltage of the protection board.
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2. The mos of the charging direction of the protection board is broken.
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3. The protection IC is broken.
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4. The device between IC command mos is broken.
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5, the NTC resistance of the protection board is bad or the resistance value is wrong -- leading to the IC that the battery is in a high temperature state ---- prohibit charging.