Why doesn't the BMS provide overcharge protection?

Overcharge Voltage Settings: The overcharge protection voltages for iron phosphate and lithium polymer batteries are 3.75V and 4.25V, respectively. Ensure that the BMS is configured correctly with these protection voltages and verify whether it complies with the battery specifications and manufacturer's recommendations.

Series Battery Balancing: In a series-connected battery pack, ensure that each individual battery receives uniform charging to prevent overcharging in any specific battery string. The BMS should be capable of monitoring the voltage of each series segment, triggering overcharge protection for the entire system if any segment exceeds the protection voltage.

Wiring Inspection: Thoroughly examine the wiring of the battery pack, ensuring that the charging negative terminal is connected to the correct position according to the wiring diagram. Check the charger connections for accuracy, and confirm that the charger's output voltage matches the battery specifications.

Hardware Issues: If all the above steps are in order and the BMS still fails to activate overcharge protection, hardware issues may be present, such as possible breakdown of the charging MOS on the protection board. In such cases, it is recommended to send the equipment to the manufacturer or qualified technicians for inspection and repair.

Firmware Updates: Ensure that the BMS firmware is up to date, as manufacturers may release updates to address potential issues or enhance performance.