The method of replenishing the No. 9 main control battery is as follows:
one
You can try to repair the charging method is to repair the battery with a pulse repair device first, remove the sulfide crystal, so that there is a chance to reactivate the battery that cannot be charged.
two
Reassemble and then check whether a single small battery is faulty, and replace the small battery if it fails.
three
Choose a charger with repair function to charge the battery, so that the battery can be automatically repaired.