The battery can’t be charged or used after long tim rest
A. Lithium batteries have self-discharge current, plus the power consumption of the protection board, so half-electric battery packs are generally required to be recharged every 3 months. Discharge to the under-voltage protection battery pack within 24H to recharge. Prevent the battery cell from being discharged to 0V to cause damage to the battery cell.

B. 0V battery charging is very unsafe. The general BMS does not support 0V battery charging. It requires more than 1V for single cell voltage to support charge .

C. If there is a GPS module or Bluetooth module that is directly powered by B+B-, then the battery pack cannot be placed for a long time. If the average power consumption of the GPS module is calculated as 10mA, it will consume 7200mAH of capacity if it is left for one month. Moreover, there is no undervoltage protection when connected to the B+B- terminal, so it is easy to discharge the battery pack to 0V.