The failure to charge is mostly due to long-time self-discharge resulting in loss of power or vulcanization.
As long as the battery is in use or has been fed for a long time, will produce varying degrees of vulcanization, and hinder future service life.
If the situation is not serious, you can try professional Chinese electric bike battery repair shop, as long as the damage is not serious, direct activation can be used.
If there is a long time serious vulcanization caused by power loss, we must not directly use your car charger charge!
Even if you are lucky enough to charge the battery, the vulcanization of the battery will become more and more serious day by day, resulting in the battery life shortened or scrapped.
The best way is to go to the professional electric battery repair shop to use a large powerful pulse machine to activate, add capacity, repair, can restore to the original battery capacity, greatly extend the battery life.