How Important is a Standby Generator Battery?
Unlike a portable generator, home standby generators require a battery. Without a battery, standby generators are useless.
Standby generators require a 12 volt battery, and choosing a battery could be a lot more important than you think. While it’s often left as a last-minute consideration, the battery must be given some careful consideration. Once the generator is installed, it will rely entirely on the battery to deliver power at precisely the right time.
The batteries are the same as you’d use for a car, but you have to be careful to select one that will meet your specific generator’s needs.
For example, here are some requirements for air cooled standby generators up to 20kW:
Generally, Generac generators require a 525cc battery (Group 26-R). Kohler air cooled standby generators generally require a 500cc battery (Group 51). Briggs generators typically require Group 26-R batteries except for 12kW units, which require a 600 CCA battery (Group 22NF).