12Power-FAULT: Under-voltage of internal power supply

The "12V Under Voltage Faulty" error signifies that the inverter's internal 12V power supply, crucial for various control and monitoring functions, is experiencing a voltage deficiency. This internal power supply is typically derived from the DC input but operates independently of the main DC bus used for power conversion.

Why it's problematic

The 12V supply powers essential components, including control circuits, sensors, and communication interfaces. A voltage drop can disrupt these functions, leading to operational failures.
A persistent under-voltage condition may indicate a problem with the inverter's internal power supply circuit, potentially requiring repair or replacement.

Possible causes

Internal inverter fault: The most likely cause is an internal malfunction within the inverter affecting the 12V power supply circuit. This could involve a faulty component like a capacitor, regulator, or transformer.
Wiring issues: While less common, problems with the DC wiring connected to the inverter, such as a short circuit or loose connection, could potentially affect the 12V supply.

Before you begin

Safety First: Working with electrical equipment always involves risks. Ensure you are qualified and follow appropriate safety precautions. Disconnect the inverter from both AC and DC sources before performing any physical inspection or adjustments.

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

Restart the inverter: In some cases, a temporary glitch might cause the error. Power off the inverter entirely, wait for a few minutes, and then power it back on.
Check DC connections: Carefully inspect the DC wiring connections to the inverter. Look for any loose connections, corrosion, or signs of damage. Secure any loose connections and clean or replace corroded parts.

Verifying the solution

Observe the inverter's display after the troubleshooting steps. If the "12V Under Voltage Faulty" error disappears, and the inverter begins normal operation, the issue is resolved.

If the problem is not resolved

If the error continues after performing the above steps, the problem likely stems from an internal inverter fault.

As a system owner: Reach out to the installer or distributor of the inverter for further assistance. You can locate installer details in the MyAutarco app.
As a certified installer: Get in touch with Autarco Support; you can initiate a support case through Helios.