If a Lithium battery is completely discharged.
Here is how to fix it.
When a lithium battery stops working and does not accept charge it may be in sleep mode. The BMS prevents the battery from completely discharging.
The common reason why the battery won’t accept charge is that the charger is unable to begin charging because the charger requires a minimum voltage before it will commence charging.
To solve this problem you need to connect a 12v source to the battery.
You will need an additional fully charged battery and jumper leads.
Connect the jumper leads from a fully charged battery to the flat battery. Positive to positive and negative to negative.
Then connect a lithium charger to the flat battery. The charger should begin charging. The battery is now awake.
Remove the jumper leads and continue charging the lithium battery until charge cycle is complete.
Some of the newer chargers feature wake up capability. This means that they will begin charging even if the battery is in a low voltage state.