Top 10 Solar Inverter Problems and How to Fix Them (2026 Guide)

1. Inverter Not Turning On

If your inverter display is blank and there are no lights, it usually indicates a power supply issue. This often happens because the DC voltage from the solar panels hasn't reached the startup threshold (common in low light) or there is a disconnection.

Solution: Check DC disconnect switches, verify MC4 connectors are tight, and measure DC voltage at the input terminals. If voltage is present but inverter is dead, the internal power supply board may be faulty.

2. Battery Not Charging

For hybrid systems, a battery not charging can be critical. This is often due to battery voltage dropping below the minimum threshold, causing the BMS (Battery Management System) to disconnect for protection.

Solution: Check battery breaker. In some cases, you may need to "wake up" the battery using a specific procedure or force-charge it from the grid if allowed.

3. Grid Connection Faults (Grid Voltage/Frequency Out of Range)

Inverters must sync with the grid. If grid voltage is too high (often due to high solar export in the neighborhood) or unstable, the inverter will disconnect to protect itself.

Solution: Measurements by an electrician are needed. If grid voltage is consistently high, adjust the inverter's grid parameters (if permitted by utility) or install a voltage optimizer.

4. Overheating Issues

Inverters generate heat. If installed in direct sunlight or a poorly ventilated area, they will derate (reduce power) to protect components.

Solution: Ensure adequate clearance around the inverter. Install a shade cover if outdoors. Check if intake fans or heat sinks are clogged with dust.

5. Isolation Faults (Ground Faults)

This widespread error indicates a short circuit between the DC system and the ground (earth). It often occurs on rainy days due to damaged cable insulation or moisture ingress in connectors.

Solution: This requires a megohmmeter (insulation tester). Specific DC strings must be isolated to find the faulty wire or panel.

6. MPPT Issues

The Maximum Power Point Tracker (MPPT) optimizes panel output. If one string is significantly shaded or mismatched, the MPPT may struggle, leading to low efficiency.

Solution: Check for hard shading on panels. Ensure all panels in a string are identical and oriented the same way.

7. Communication Failures

Can't see your data on the app? Communication faults between the inverter and the router are common.

Solution: Reset the WiFi module/stick. Check WiFi signal strength at the inverter location. Update inverter firmware.

8. Fan Noise and Vibration

As inverters age, cooling fans can wear out, causing loud noises or failure to cool.

Solution: Clean fan filters. If noise persists, replace the cooling fan assembly.

9. DC Arc Faults

Arc faults occur when there is a loose connection sparking (arcing). Modern inverters detect the "noise" of an arc and shut down to prevent fire.

Solution: Visually inspect all DC connections for burn marks or melted plastic. Tighten all terminals. This is a serious safety risk.

10. Firmware Errors

Software glitches can cause erratic behavior or false error codes.

Solution: Check the manufacturer's portal for remote firmware updates. A factory reset (saving settings first) can sometimes resolve persistent glitches.