Battery and charger problems
A standby generator involves utility-voltage electricity, fuel gas, moving parts, and equipment that can start automatically. This page describes what manufacturer documents say an owner can observe or set from the controls — it is not repair instructions. Follow the safety warnings and shutdown steps in your unit's manual before approaching the unit, and leave work inside the equipment, transfer switch, or fuel and electrical systems to an authorized dealer or licensed electrician.
What this means
- Per the 10–24 kW owner's manual, the battery charger is integrated into the control module on all covered models and operates as a smart charger; Generac instructs owners not to use external battery chargers, displays a warning on the LCD when the battery needs service, and directs owners to contact a dealer if the screen displays "CHARGER MISSING AC." (Generac Power Systems, Inc. archived source, retrieved 2026-07-09; Verified Fact; EV-GEN-EVO-0002#C3)
Common causes
- On Kohler RDC2/DC2 controllers, displayed faults are classified as either a Warning (the unit keeps operating) or a Shutdown. "Lo Crank Vlt" is documented as a Warning meaning battery voltage fell below 8 VDC for more than 6 seconds while the starter was engaged, with the documented remedy to charge or replace the battery; frequency-high and frequency-low conditions are Shutdowns that direct the owner to an authorized distributor/dealer. (Kohler Co. archived source, retrieved 2026-07-09; Verified Fact; EV-KOH-ERR-0003#C2)
What to check first
Verified guidance for this section has not been published yet.
When to call a professional
Verified guidance for this section has not been published yet.
Safety and warranty considerations
Verified guidance for this section has not been published yet.