RTC ERROR
OpenEVSE Real-Time Clock Communication Failure

Display shows 'RTC ERROR' or time-based scheduling does not work correctly.

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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

Failed RTC chip on main board, Dead or missing RTC backup battery, I2C bus fault between MCU and RTC, Corrupted RTC configuration

How to Fix / Troubleshooting

Safety first: Disconnect power before working on the main board.

  • Step 1 – Check time settings: Attempt to set the date and time via the LCD or Wi-Fi interface. If the time will not save or drifts immediately, the RTC may be faulty.
  • Step 2 – Inspect RTC area: On the main board, locate the RTC chip and any associated coin-cell battery. Look for corrosion or leakage from the battery.
  • Step 3 – Replace battery: If a backup battery is present and old, replace it with the exact specified type, observing polarity.
  • Step 4 – Firmware reset: Perform a configuration reset or RTC reinitialization if supported by firmware, then re-enter the correct time.
  • Step 5 – Board replacement: If the error persists, the RTC chip or I2C bus on the main board is likely defective. Replace the main control board.
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Repair Difficulty

Medium 3/5

Required Part

OpenEVSE Main Control Board
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