GM Service Manual Online
For 1990-2009 cars only

Battery Charging Specifications Optima

Recommended Charging Rates

Generator 12V

13.8 V to 15.0 V

Generator 24V

27 V to 32 V

Generator (Amps)

No Limit

Battery Charger Charging

Battery Charger (12V)

14.8 V

Battery Charger 12V (Amps)

13.75 A

Battery Charger Time (Maximum)

24 Hours

Constant Voltage Charging

Constant Voltage (Volts)

14.7 V to 15.0 V

Constant Voltage Temperature

122°F (50°C)

Constant Voltage (Amps)

No Limit

Constant Voltage Time

Charging falls below 1 A, then 2 A for 1 hour

Float Charge

13.2 V to 13.8 V