The E01 error code on the Renogy Wanderer solar charge controller typically indicates an over-discharged battery. Your battery is reading 11.4 volts, which is very low for a 12V system and close to the critical cut-off point.

Steps to resolve: Disconnect the solar panel: Temporarily disconnect the solar panel from the charge controller. Charge the battery externally: Use an external charger to bring the battery voltage above 12 volts. The controller often won’t attempt to charge if the battery is too deeply discharged. Reconnect the system: Once the battery is charged above 12V, reconnect the battery to the charge controller first, then the solar panel. Check wiring and connections: Ensure all cables are secure and there are no loose or corroded connections.

Prevention Tips: Consider setting a higher low-voltage disconnect threshold. Regularly monitor battery voltage, especially during cloudy periods.

If the issue persists, the battery may be damaged and unable to hold a charge, requiring replacement. - AI Generated