Safety: High charging voltage can cause batteries to gas excessively. Ensure good ventilation around the battery compartment.

Measure voltage: With a multimeter, measure battery voltage with charger on and engine stopped. If above recommended float voltage (e.g., >14.4 V for 12 V, >28.8 V for 24 V), suspect the charger.
Check charger settings: Many chargers have selectable voltage or battery type. Confirm it is set for the correct system voltage and battery chemistry.
Inspect alternator regulator: If high voltage occurs only when the engine is running, the engine‑mounted charging alternator or its regulator may be faulty. Test alternator output and replace the alternator regulator if necessary.
Verify controller reading: Compare controller‑displayed battery voltage with your meter. If they differ significantly, check the sensing wires and controller analog input calibration.
Replace faulty charger: If the charger output remains too high despite correct settings, replace the battery charger with a suitable unit.

Controller shows E013 and indicates battery voltage high

Possible Causes