If the batteries were discharged completely, the battery charger isn't strong enough to start the charging process. Take the batteries out and charge each one separately with an automotive type battery charger that is NOT automatic. This may take a day to recover this way. When the battery shows over 10 volts with a dc voltmeter you can re install them in the chair to complete the charge with the 24 volt charger. If the batteries have any amount of age past 2 years, it's time for new batteries.
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If the batteries were discharged completely, the battery charger isn't strong enough to start the charging process. Take the batteries out and charge each one separately with an automotive type battery charger that is NOT automatic. This may take a day to recover this way. When the battery shows over 10 volts with a dc voltmeter you can re install them in the chair to complete the charge with the 24 volt charger. If the batteries have any amount of age past 2 years, it's time for new batteries.