Generator will not start; controller shows E10 immediately after the start command.

Safety first: Disable AUTO mode and ensure the generator cannot start unexpectedly.

• Measure battery voltage: Use a multimeter at the battery posts. If below about 11.8 V, the battery is deeply discharged.
• Charge or replace battery: Remove and bench-charge the battery with an appropriate charger. If it will not hold a charge or fails a load test, replace with a battery that meets Wacker Neuson CCA and capacity specs.
• Inspect charger: With AC supply present, measure the output of the built-in battery charger (often 13.4–13.8 V DC). If no output, check fuses and wiring; replace the charger if defective.
• Clean and tighten terminals: Remove corrosion from posts and clamps. Reinstall and tighten securely. Check the ground strap to the frame.
• Controller settings: Verify that the controller's battery type and float voltage settings (if adjustable) match the installed battery.
• Reset E10: After restoring proper voltage, clear the code and test start.