storagefaults.comstoragefaults.com

SolarEdge•Unknown

Analysis by Marcus & Team

SolarEdge Hybrid Inverter Error 18xB5 AC Protection Board Fault

Diagnose and fix SolarEdge 18xB5 AC protection fault. Understand causes, solutions, safety precautions & maintenance for residential hybrid inverters.

Frequently Asked Questions

•What is the typical lifespan of an AC protection board in a SolarEdge inverter?

The lifespan varies based on environmental conditions (temperature, humidity, surge frequency) and usage, but typically ranges from 5-10 years. Installing surge protection can extend its lifespan.

•Can I replace the AC protection board myself?

No. Due to high voltage hazards and NEC requirements, only a qualified electrician should replace the AC protection board. Incorrect installation can lead to serious injury or equipment damage.

•Where can I find the SolarEdge service manual for my inverter model?

The SolarEdge service manual is generally accessible to certified SolarEdge installers and service providers. Contact your installer or SolarEdge support for access. It contains detailed procedures and component specifications.

Related questions

Loading related questions...

Marcus leads the technical research department at Storage Faults. Together with a team of systems analysts, he specializes in translating complex solar storage error codes into actionable diagnostic steps for the US market.

← Back to list

Expert Tip:

Before replacing the AC protection board, try a DC reboot of the inverter. Simultaneously disconnect both the AC and DC disconnects for at least 15 minutes. This can sometimes clear temporary faults and reset the protection circuitry. After reboot, check the SolarEdge monitoring portal for updated status.

Safety Warning:

High voltages are present within the inverter. Only qualified electricians should perform diagnostic and repair work. Follow all NEC guidelines and manufacturer's safety procedures. Arc flash hazards exist. Wear appropriate PPE (Personal Protective Equipment), including insulated gloves and safety glasses. Verify rapid shutdown is active and functional. Never work on live circuits.

Technical Overview:

The SolarEdge hybrid inverter integrates PV power conversion, battery charging/discharging, and grid interaction. The AC protection board monitors AC voltage and current, providing overvoltage, undervoltage, overcurrent, and frequency protection. It disconnects the inverter from the grid under fault conditions to prevent damage and ensure safety. This board is crucial for anti-islanding protection and grid synchronization. It typically houses relays, MOVs (Metal Oxide Varistors), and sensing circuitry.

Step-by-Step Fix:

1

*Safety First**: Disconnect the AC and DC disconnects to the inverter. Verify zero voltage on AC and DC conductors using a calibrated multimeter. Consult the SolarEdge system manual for safe disconnection procedures.
2

*Visual inspection**: Carefully inspect the AC protection board for signs of physical damage, such as burned components, bulging capacitors, or cracked traces. Use an insulated flashlight for better visibility.
3

*Wiring Check**: Verify all AC wiring connections to the inverter are secure and free from corrosion. Tighten any loose connections according to the manufacturer's torque specifications.
4

*Component Testing**: Using a multimeter, test the MOVs on the AC protection board for continuity and proper resistance. Compare readings to known good values or the component datasheet.
5

*Relay Testing**: If possible, test the relays on the AC protection board for proper operation using a multimeter and a low-voltage power supply. Check for coil continuity and contact resistance.
6

*Firmware Update**: If no hardware issues are found, attempt to update the inverter's firmware to the latest version using the SolarEdge SetApp. This may resolve software-related glitches.
7

*Board Replacement**: If hardware damage is confirmed or suspected, replace the AC protection board with a new, genuine SolarEdge replacement part. Ensure correct part number and compatibility. Refer to the SolarEdge service manual.

Observed Symptoms:

The SolarEdge hybrid inverter displays error code 18xB5, indicating a fault within the AC protection board. The inverter may shut down and cease AC power output. Grid connectivity may be lost. Backup power functionality (if available) may be unavailable. Monitoring portal displays the 18xB5 error.

Common Causes:

Damaged MOV due to voltage surge (lightning strike, grid transient).
Relay failure on the AC protection board (stuck open or closed).
Faulty voltage or current sensing circuitry on the board.
Loose or corroded AC wiring connections to the inverter.
Firmware or software glitch within the inverter's control system affecting AC protection logic.
Manufacturing defect within the AC protection board itself.

Prevention:

Install surge protection devices (SPDs) on both the AC and DC sides of the inverter to protect against voltage surges.
Periodically inspect wiring connections for tightness and corrosion.
Keep the inverter's firmware up-to-date to benefit from the latest bug fixes and improvements.
Monitor the inverter's performance data regularly for any signs of anomalies or potential issues.
Follow the manufacturer's recommended maintenance schedule.