Parts & compatibility
Which battery does my standby generator need?
Choose the exact model. We show only battery specifications that have been verified against manufacturer documentation instead of assuming every generator from the same brand uses the same battery.
V1 verified models
Find your battery
If your exact model is not listed, do not assume another model uses the same battery. We are expanding this database only when specifications are verified.
Generac Guardian 18kW
Flooded 26R or AGM Group 35, as specified
View official sourceWhy the exact model matters
Battery requirements can change even within one manufacturer's residential lineup. Group size, physical dimensions, cold-cranking-amp minimums, chemistry and quantity can all differ. A battery that is correct for one 18 kW unit may not fit or meet the requirements of a newer 22 or 26 kW model.
Match the nameplate
Use the exact model/model number, not only the brand or advertised kW.
Check current documentation
Model revisions can change parts and specifications. Confirm against the current manual or manufacturer page.
Respect electrical safety
Battery replacement is not permission to work inside energized transfer equipment or other live electrical systems.