Every solar inverter brand has its own error codes, but the underlying problems are remarkably similar. Here are the issues our technicians see most often across Growatt, Solis, Sungrow, GoodWe, Huawei, SMA, Luminous and other inverters — and how each one is solved.
Problem: Grid voltage or frequency errors
Solution: Measure the grid voltage at the inverter terminals during peak generation. Undersized or long AC cables raise the voltage seen by the inverter. Upgrading the cable, tightening terminations or adjusting settings within permitted limits usually fixes it. If the grid is normal, the inverter's sensing circuit or relay may need repair.
Problem: Isolation / insulation fault
Solution: Test the insulation resistance of each string to find the faulty one, then inspect its cables, connectors and junction boxes for damage or water ingress.
Problem: Overheating and derating
Solution: Clean heat sinks and fans, replace failed fans, and shade the inverter or move it out of direct sun with proper ventilation clearance.
Problem: Frequent tripping
Solution: Check whether it is the inverter tripping or the AC breaker. Undersized breakers, loose connections and earth leakage are frequent causes.
Problem: Battery not charging (off-grid / hybrid)
Solution: Verify battery health and settings, check fuses and solar input, then test the charge controller and MOSFETs.
Problem: Display not working
Solution: If the inverter still generates, it is likely a display board or cable fault. If it does not, the auxiliary supply may have failed.
Problem: Low efficiency / low generation
Solution: Compare string-wise currents. One weak string often reveals shading, dirty panels, a failed connector or an MPPT fault.
Problem: Monitoring offline
Solution: Usually a Wi-Fi password change, router issue or failed data logger — not an inverter failure.
Need a solar inverter repaired?
Share your inverter brand, model and error code — our technicians will guide you and share an estimate before any repair starts.