E3
Honda
Battery Charging Fault / Overvoltage or Undervoltage Detected
Robot mower displays E3 and will not leave the charging station.
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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
Aged or failed battery pack, Defective charging power supply, Faulty battery temperature sensor, Damaged charging harness
How to Fix / Troubleshooting
Safety first: Switch OFF the mower and disconnect the charging station from mains power before inspection.
- Check ambient temperature: Ensure the mower and charging station are not exposed to extreme heat or direct sunlight. Very high or very low temperatures can trigger charging protection.
- Inspect battery pack: Open the battery compartment and check for swelling, leakage, or odor. If any are present, do not use the mower; the battery must be replaced.
- Check charging power supply: Verify the LED on the Honda power adapter (if equipped) is lit. If not, test the outlet with another device. Replace the adapter if it shows no output.
- Reseat connectors: Disconnect and reconnect the battery plug and the internal charging harness to the main control board to ensure solid contact.
- Reset system: With the mower off, disconnect the battery for 2–3 minutes, reconnect, then place the mower on the station and power it up to see if E3 clears.
If E3 remains, the battery pack or charging circuitry on the main PCB is likely defective and should be diagnosed with Honda‑specific test equipment.
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Repair Difficulty
Hard
4/5
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