Generator stops and controller displays AL07 indicating battery low voltage alarm.

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

• Measure battery voltage: With the charger connected, measure DC voltage at the battery terminals. For 12 V systems expect ~13.5–13.8 V; for 24 V systems ~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 AC supply to the SDMO battery charger module. If AC is present but output is low or zero, replace the charger. Inspect DC output fuse if fitted.
• Reset alarm: After correcting the issue, clear AL07 and confirm that the controller shows normal battery voltage.