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SolarEdge•Unknown

Analysis by Marcus & Team

SolarEdge Inverter Error 18xB2: DC Injection Line 2 High

Diagnosing SolarEdge Error 18xB2 (DC Injection Line 2 High) in residential hybrid inverters. Causes, solutions, and safety for homeowners.

Frequently Asked Questions

•What is the typical open-circuit voltage (Voc) for my PV array?

The Voc depends on the specific PV module model, number of modules in series, and temperature. Consult the module datasheet and use online calculators to estimate the Voc at different temperatures.

•How do I activate the rapid shutdown system (RSD) on my SolarEdge inverter?

The RSD activation method depends on the specific system configuration. It typically involves a dedicated switch or breaker labeled 'Rapid Shutdown.' Consult the system's documentation for instructions.

•Where can I find a qualified electrician to service my SolarEdge inverter?

Contact SolarEdge directly or search online directories for electricians specializing in solar PV systems. Ensure the electrician is licensed and certified to work on PV systems in your jurisdiction.

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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.

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Pro Tip:

Access the SolarEdge inverter's service menu (consult the service manual for the key combination) to view detailed diagnostic data, including DC injection current levels on each input line. Compare the values to the manufacturer's specifications to identify the source of the problem. Use the inverter's self-test function (if available) to run diagnostic tests on internal components.

Critical Safety Precautions:

Solar PV systems operate at high DC voltages, posing a significant electrical shock hazard. Only qualified electricians with experience working on PV systems should perform diagnostic and repair work. Always disconnect both AC and DC power before working on the system. Wear appropriate personal protective equipment (PPE), including insulated gloves and safety glasses. Consult the inverter's system manual for specific safety instructions. NEC Article 690 covers solar photovoltaic (PV) systems.

Step-by-Step Fix:

1

Disconnect the AC power to the SolarEdge inverter using the AC disconnect switch. Consult local regulations for proper disconnection procedures.
2

Activate the rapid shutdown system (RSD) according to NEC 2017/2020 guidelines. Verify voltage at the array is below safety thresholds using a calibrated multimeter. Record the voltage.
3

Isolate the DC input line 2 by disconnecting the DC connectors. Measure the open-circuit voltage (Voc) of the string connected to line 2 with a multimeter. Compare to expected Voc based on module specifications and temperature.
4

Perform an insulation resistance test (megger test) on the DC wiring connected to line 2 to check for ground faults. A reading close to zero indicates a ground fault.
5

Inspect the PV modules in the string connected to line 2 for any physical damage, discoloration, or signs of overheating. Use an IR thermometer to check for hotspots.
6

Use a DC clamp meter to measure the current in each string while the system is operating (if safe to do so before disconnecting). Compare the current readings to identify any strings with abnormally high or low current.
7

If no external faults are found, the inverter itself may be faulty and require replacement or repair by a qualified SolarEdge service technician.

How It Works:

Hybrid inverters manage power flow from solar panels, battery storage, and the grid. DC current injection refers to the presence of DC current in the AC output. This is undesirable as it can saturate transformers and damage grid-connected equipment. Error 18xB2 specifically implicates DC input line 2, typically connected to a specific string of PV modules. The inverter's anti-islanding protection system is designed to prevent DC injection onto the AC grid. Internal sensors monitor DC current levels. The MPPT algorithm optimizes power extraction from the PV array, while DC/DC converters regulate voltage levels.

Common Causes:

Failed or shorted PV module(s) in string connected to DC input line 2.
Ground fault on the DC wiring or PV array connected to input line 2.
Internal component failure within the SolarEdge inverter's DC/AC conversion stage, specifically affecting DC input line 2.
Loose or corroded DC connector on line 2.
Damaged DC wiring insulation, leading to leakage current.
Incorrect grounding or bonding of the PV array.

Observed Symptoms:

SolarEdge inverter displays Error 18xB2, indicating excessive DC current injection on DC input line 2. The inverter may shut down or derate its output power. This is observed through the SolarEdge monitoring app or directly on the inverter's display.

Prevention:

Regularly inspect PV module wiring and connectors for signs of corrosion or damage.
Schedule periodic insulation resistance testing of the PV array.
Monitor the SolarEdge monitoring portal for any error codes or performance anomalies.
Keep the inverter clean and free of debris to ensure proper ventilation.
Ensure proper grounding and bonding of the PV array and inverter.