Charger displays E305; app may show 'RTC error' or 'Clock synchronization failed'.

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.

Possible Causes

Depleted RTC backup battery on control board, Firmware bug affecting time sync, Loss of NTP access over network, Failed RTC chip on board

Note: This mainly affects scheduled charging and logging, not basic charging safety.

Check network time: Ensure the charger has internet access so it can sync time via NTP.
Disable schedules temporarily: In the Enphase app, disable scheduled charging and test immediate charging.
Firmware update: Apply any available firmware updates that may address RTC issues.
If error persists offline: The RTC battery or chip may have failed. A technician can replace the control board to restore reliable timekeeping.

Medium 3/5

Enphase EV Charger Control Board RTC Circuit

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