Is the battery charger working correctly? Could there be a problem with the wiringor other components of the wheelchair?
You can determine the nextstep in the troubleshooting process once you know the voltage of each battery.

My batteries were over-discharged and my batterycharger will not start. What do I do?
Have you ever had a customer state that their batteries will not takea charge even though the charger was plugged in overnight? When you checked theirbatteries, you found that they both read 9 volts? This is usually due to a lightor a brake being left on for an extended period of time, which drains the batteries.

Thereason why the charger is not working is that most wheelchair battery chargersneed to read at least 21-22 volts in order to begin charging. This is how thepolarity protection system of many chargers works.If the user were to hook upthe positive and negative backwards, nothing would happen to the charger or thebatteries because the batteries never read any voltage so it never started.

The drawback to this polarity protection design is whena user over-discharges their batteries below the 21-22 volt cutoff. Althoughthe charger is connected, it does not receive the signal to begin the chargingprocess so the batteries never get charged.

The best way to solve this problem is to remove thebatteries from the wheelchair and charge each battery separately with a 12-voltbatterycharger. When each battery is fully charged, they can then be reinstalled inthe chair and returned to service. Note: It may take the batteries up to 15cyclesto return to their former capacity if they have been severely discharged.