RelayChk-FAIL: Relay fault 

The relay fault in Autarco solar inverters can occur due to several reasons including mechanical failure, environmental factors, electrical issues, and communication problems. This can interrupt the normal operation of the solar system, leading to decreased energy production and potential system downtime.

Possible causes

• Mechanical failure from wear and tear
• Exposure to extreme temperatures, high humidity, or moisture
• Voltage fluctuations, overcurrent, or short circuits
• Communication failures between the inverter and other system components
• Improper wiring, loose terminals, or inadequate grounding

Before you begin

Gather Information: Before starting troubleshooting, have the inverter manual on hand. You should also gather information about the inverter model and serial number, the installation date, and the PV array configuration (number of panels, capacity, and number of strings).

Troubleshooting steps

1. Inverter Discharge:
   • Discharge the Autarco inverter for 30 minutes.
   • If the inverter resumes normal operation when restarted, the issue is resolved.
2. Wire Connection Inspection:
   • Verify the proper connection of the AC gland, especially for new installations.
   • Ensure the AC cable is securely connected to the connector terminal, following the indicated polarity on the AC gland.
   • Inspect all wire connections from the AC connectors to the AC distribution box, meter side, LT panel, and transformer side.
   • Look for any loose or untightened connections and assess the wire contact area.
   • If you suspect a loose connection, carefully disconnect the cable from the connector, AC distribution box (ACDB), and the meter/grid source.
   • Re-establish a secure and proper connection for the cable, ensuring all connections are tightly secured.
   • Check the earthing cable size and ensure proper connectivity.
3. Voltage Checks:
   • Conduct voltage checks on the AC side for phase-to-phase, phase-to-neutral, and neutral-to-earth readings.
   • Measure readings from the inverter AC gland end.
   • For single-phase systems, check AC side voltage for phase-to-neutral, phase-to-earth, and neutral-to-earth readings.
   • Ensure measurements are taken from the inverter AC gland end.
   • Capture comprehensive readings from information menus such as DC1, DC2, DC3, DC4, followed by VA, VB, VC, or VGrid, and check the Status (Error) and Total energy.
4. PV String Voltage Checks:
   • Verify the Open Circuit Voltage (VOC) of each PV string by measuring the voltage from the connector end after disconnecting the string from the inverter.
   • Use a multimeter to measure the voltages between PV+ and earth, as well as PV- and earth for all the PV strings.
   • The voltages should decrease and fall within the range of 5% to 95% of the Voc of a single PV module.
   • If the voltage remains constant at the Voc of a single module or increases during the decreasing conditions, it indicates a fault within the PV strings that needs to be addressed.

Validating the solution

After following the troubleshooting steps, the system should resume normal operation. The inverter should no longer display the relay fault error, and the readings from the menus should reflect normal operation values.

If the problem is not resolved

If the error persists after following all the above steps, there might be an internal fault within the inverter.

• As a system owner: In this case, contact the inverter installer or distributor for further assistance. You can find the details of your installer in the MyAutarco app.
• As a certified installer: Contact Autarco Support, you can submit a support case via Helios.