we have four of these batteries.. and three already don't charge.   any advice?  i don't think they are that old.  maybe a year or littlie over?

Thank you

Hello, there. Sorry for your inconvenience. Would you please check the following steps?
1. Check whether the battery level indicators will turn on when charging.
2. If the battery level indicators do not turn on, clean the charger and the battery contact pins with absolute alcohol. Recharge the battery and try again.
3. If possible, use another battery or charger to check whether the battery or the charger is malfunctioning.
4. If the issue persists after the above steps have been tried, please contact our support to create a case and send batteries back if the battery is under warranty.
Tips for battery maintenance:
Charge and discharge the battery every 2 months to keep it in good condition. Discharge the battery to between 40% - 60% if the battery will not be used for 10 days or longer. This can extend the battery life. The battery automatically discharges to approximately 65% when it is idle for more than 10 days to prevent it from swelling.