AL08
FG Wilson
High DC Battery Voltage
Generator controller shows AL08 – Battery Voltage High while on float charge
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Battery charger overvoltage, Incorrect charger setting for battery type, Faulty charger voltage sensing, Loose battery sense wiring
How to Fix / Troubleshooting
Safety first: Isolate AC supply to the battery charger before working on it. Keep the generator in STOP.
- Measure DC voltage: With a multimeter, check the battery voltage at the terminals. Compare with the controller reading. For a 24 V system, float voltage should typically be around 27.0–27.6 V.
- Inspect charger settings: On the FG Wilson charger, verify that the voltage selector or DIP switches are set for the correct system voltage (12/24 V) and battery type (lead-acid/AGM).
- Check charger sense leads: Some chargers use separate sense wires; ensure they are correctly connected and not open-circuit.
- Adjust or replace charger: If the charger output is above specification and not adjustable, replace it with an approved FG Wilson-compatible charger.
- Retest: Restore AC to the charger and confirm that voltage stabilizes within the recommended range and the alarm clears.
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Repair Difficulty
Medium
3/5
Required Part
Battery Charger
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