The generator stops and the controller displays AL07, indicating a battery low voltage alarm.

Safety first: Set the controller to OFF and isolate the AC output. Wear eye protection when working around batteries.

• Measure battery voltage: With the charger connected, measure the DC voltage at the battery terminals. For 12 V systems, expect ~13.5–13.8 V; for 24 V systems, expect ~27–27.6 V. If significantly lower, suspect the charger or battery.
• Inspect terminals and cables: Clean corrosion from battery posts and cable lugs using a wire brush. Tighten all connections to the SDMO starter and ground points.
• Test battery capacity: Perform a load test with an appropriate tester. Replace the SDMO starter battery if it fails to maintain voltage under load.
• Check battery charger: Verify the AC supply to the SDMO battery charger module. If AC is present but the output is low or zero, replace the charger. Inspect the DC output fuse if fitted.
• Reset alarm: After correcting the issue, clear AL07 and confirm that the controller shows normal battery voltage.