Read the manual thoroughly and understand all of the instructions, cautions, and warnings before using this equipment. If any section of the manual is not understood, contact your nearest authorized dealer, or contact Generac Customer Service at 1-888-436-3722 (1-888-GENERAC), or www.generac.com with any questions or concerns. 

Replacing the generator's battery

Generator owners should reference these articles before performing maintenance on the generator:

• Maintenance Schedule: See the Where Can I Find the Maintenance Schedule for My Generac Home Standby Generator? article for information about generator service schedules.
• Maintenance Safety: Owners should reference What Safety Precautions Should I Take When Performing Maintenance on My Generator? to ensure maintenance is performed in a safe manner.
• Maintenance Kits: Generac sells maintenance kits that bundle OEM parts for maintenance tasks. See the What Are Generator Maintenance Kits? article for more information.
• Authorized Service Dealers: While generator owners can certainly perform maintenance tasks, scheduled maintenance tasks can also be completed by a certified service dealer. See How Can I Find a Generac Service Dealer in My Area? for more information.
• Consult the User Manual: The process covered in this article applies to air-cooled Guardian (10-26 kW) series generators. Owners should always reference the user manual for maintenance tasks. See How Do I Find a Copy of My Home Standby Generator Owner's Manual, Spec Sheets, or Installation Manual? for more information.

Environment

This article applies to 10 kW - 26 kW Guardian series generators manufactured after 2017. Maintenance information for all generator models can be found in the generator owner's manual.

Before you begin

Verify the correct battery will be installed. See What Battery Do I Need for My Home Standby Generator? for information about compatible batteries.

Verify the battery requires replacement. Reference How Do I Inspect the Battery On My Home Standby Generator? for steps to inspect and service the current battery.

Video instructions

To replace the generator's battery

1. Lift the generator's lid and set the generator main line circuit breaker (MLCB) to off.

2. Press the OFF button on the generator control panel. This will prevent the generator from starting in the following step.

3. Set the utility main line circuit breaker (MLCB) to off. See What is a service entrance disconnect and how can I tell if it's on or off? for more information.

Note: Setting the utility main line circuit breaker (MLCB) to off will shut off the utility power to the home until the utility MLCB is restored to the on position.

4. If running during an outage, allow the generator to run and cool down for five minutes with no load applied.

Note: Setting the generator main line circuit breaker (MLCB) to off removes the load from the generator. Failure to remove the load and cool down before shutting the generator off can cause damage.

5. Press the OFF button to power off the generator. Then remove the front panel. See How do I remove the front panel on my home standby generator? for steps to remove the front panel.

6. Allow the generator to cool for an additional five minutes before working on it.

7. Remove the 7.5 amp fuse from the generator's control panel to prevent the battery from draining. This is located underneath the rubber flap (B) shown in Figure 1-1.

Figure 1-1

8. Remove the intake side panel. See How Do I Remove the Generator Side Panel? for more information.

9. Disconnect the white battery charger cable located beneath the control panel, shown in Figure 1-2.

Figure 1-2

10. Be sure the wrench never makes contact with both posts at the same time. This will cause a short and can be very dangerous. Disconnect the battery, removing the negative battery cable first and then the positive cable.

11. Remove the disconnected battery and insert the new battery.

12. Connect the positive battery cable first and then the negative battery cable.

13. Tighten the battery cable lugs with a wrench. Again, avoid damage and injury by preventing the wrench from making contact with both battery posts at the same time.

14. Reconnect the battery charger cable.

15. Reinstall the intake side panel and the front panel.

16. Reinstall the 7.5A fuse.

17. When the control panel boots up, the install wizard should appear.

18. This will allow you to set the current time and date (military time).

19. Set the generator's main line circuit breaker to ON.

20. Set the utility main line circuit breaker to ON, restoring utility power to your house.

21. Place the generator in auto mode.

22. The generator is now ready to run in the event of a power outage.

23. Close the generator lid.