Our the BMS has cut-off function for battery protecting,
First, need to cut off the battery load and put the battery leave aside at least 30mins.
Second, let the battery automatically reach to normal voltage and then you can use once fully charged.
If the battery can't reach to normal volatage and its voltage is too low to hold a charge, there are two ways to re-activate it
① the charger with 0V charging function ( charge batteries starting from 0V) can use for charging battery.
② Use another new 12V lithium battery in parallel with the old one at least 1 minute to re-activate the battery.
