IF your BMS allows the battery to go below the charging state that your SMART CHARGER won't charge, simply apply 12+ volts from another battery to the LIVPO4 battery and connected charger for less than a second, and after that spark, the charger will bring the LIVPO4 battery back to full state.
So, the BMS won't allow the battery to be overly discharged, however the BMS will SHUT DOWN the battery, to protect the battery from overly discharging, and the smart charger won't see the battery.
That spark fools the BMS and the charger.
I've come back to no lights, etc. and had to do this many times without damage to battery or charger.