Kubota standby generator battery repeatedly goes dead between exercise runs, even though the charger is connected.

Safety first: Wear eye protection when working around batteries. Disconnect battery negative before servicing wiring.

• Test charger output: With AC power present, measure voltage at the battery terminals. It should be around 13.4–13.8 V. If lower, test charger output directly and replace if weak.
• Check for parasitic draw: With the generator off and charger disconnected, place an ammeter in series with the battery negative. Current draw should be low (typically <100 mA). Higher draw indicates a parasitic load that must be traced and corrected.
• Battery condition: Perform a load test on the battery. Replace if it fails or is older than manufacturer’s recommended service life.
• Connections: Clean and tighten all battery and ground connections, including the ground strap to the frame.
• Exercise schedule: Ensure the generator runs its automatic exercise cycle regularly to keep the battery in good condition.