Electrical
Charging a Maintenance Free Battery
Using a Variable Rate Charger (Maintenance Free Batteries)
Set the charging voltage to 16-17 V.
No
Yes
Connect a charger and ammeter to
the battery and start charging.
Adjust the voltage to obtain the
standard charging amperage.
Monitor the amperage for 3‐5
minutes. Is the standard charging
amperage exceeded?
Set the timer to the charging time
determined by the open circuit
voltage.
If the amperage does not exceed the
standard charging amperage after 5
minutes, replace the battery.
Let the battery sit for 30 minutes,
then measure the open circuit
voltage.
12.8 V or more Charging is complete
12.0‐12.7V Recharging is required.
If the required charging time exceeds
5 hours, recheck the charging
amperage and adjust the voltage to
obtain the standard charging
amperage.
Adjust the charging voltage to 20‐25 V.
Is the amperage higher than the
standard charging amperage written
on the battery?
Measure the open circuit voltage.