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SolarEdge•Optimizer

Analysis by Marcus & Team

SolarEdge Optimizer: 'Optimizers Missing' on String Issue

Troubleshooting 'Optimizers Missing' error on SolarEdge systems. Identify string faults, optimizer failures, and connection issues. Expert diagnostics and solutions.

Frequently Asked Questions

•What are the typical DC voltage ranges for SolarEdge optimizers?

Typical DC input voltage ranges for SolarEdge optimizers are between 12.5V and 48V, but this can vary depending on the specific optimizer model. Refer to the optimizer's datasheet for accurate specifications.

•How does shading affect the performance of SolarEdge optimizers?

SolarEdge optimizers mitigate the impact of shading by allowing each PV module to operate at its maximum power point, even if other modules in the string are shaded. This helps maintain overall system performance.

•What are the common causes of optimizer failure?

Common causes of optimizer failure include component degradation due to heat or moisture, surge events, and manufacturing defects. Regular monitoring and preventative maintenance can help minimize the risk of failure.

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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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Observed Symptoms:

String 2 of the SolarEdge system reports "Optimizers Missing" while String 1 operates normally. The SolarEdge monitoring portal or app displays an error related to String 2 optimizer communication. Power production from String 2 is significantly reduced or absent.

Technical Recommendation:

Use the SolarEdge SetApp with Installer access to perform individual optimizer testing. The SetApp allows you to communicate directly with each optimizer and view its voltage, current, and temperature readings. This allows for faster identification of problematic optimizers within the string. Remember to follow manufacturer guidelines for using the SetApp.

Safety Warning:

Solar PV systems operate at high DC voltages (up to 600V or higher). Improper handling can result in serious injury or death. Always disconnect the DC supply before performing any maintenance or repairs. Follow NEC rapid shutdown procedures to de-energize the system. Work must be performed by a qualified electrician wearing appropriate personal protective equipment (PPE), including insulated gloves and eye protection. Arc flash hazards exist.

Technical Overview:

SolarEdge systems utilize DC power optimizers connected to each PV module. These optimizers individually maximize power output from each module and communicate performance data to the inverter. The inverter then aggregates and converts the DC power to AC for grid export or battery charging. Loss of communication from multiple optimizers in a string triggers the "Optimizers Missing" fault. This can be due to wiring issues, optimizer failures, or inverter communication problems. Each optimizer reports voltage, current, and temperature data to the inverter.

Why This Happens:

Wiring Fault: Damaged or loose wiring connections within String 2 affecting optimizer communication.
Optimizer Failure: One or more optimizers in String 2 have failed, disrupting communication for the entire string.
String Voltage Imbalance: Significant shading or module mismatch within String 2 causing voltage deviations outside the optimizer's operating range.
DC Disconnect Issues: Improperly closed or faulty DC disconnect switch isolating String 2.
Inverter Communication Problem: Failure of the SolarEdge inverter to properly communicate with optimizers specifically on String 2.
Firmware Bug: Rare instances of software glitches on the inverter causing misreporting.

Recommended Action:

1

*Safety First**: Engage a qualified electrician familiar with SolarEdge systems and NEC rapid shutdown requirements.
2

*DC Disconnect**: Verify all DC disconnects for both strings are fully engaged. Use a calibrated multimeter to measure DC voltage at the inverter terminals for both strings.
3

*String Voltage Test**: With the system shut down and DC disconnected, use a multimeter to measure the open-circuit voltage of each string at the inverter input terminals. Compare String 1 and String 2 voltage readings. A significant difference suggests a problem in String 2.
4

*Optimizer inspection**: Visually inspect all optimizers in String 2 for physical damage (cracks, corrosion, burn marks). Note the serial number of each optimizer for record keeping.
5

*Optimizer Continuity Test**: With the system shut down, use a multimeter to perform a continuity test on the DC wiring between each optimizer in String
6

Look for open circuits or shorts.
7

*Isolate Faulty Optimizer**: If continuity testing reveals a faulty optimizer, replace it with a compatible SolarEdge optimizer. Ensure proper torque is applied to all connections.
8

*Inverter Diagnostics**: Use the SolarEdge SetApp or monitoring portal to check for error messages related to optimizer communication. Consider contacting SolarEdge support for inverter firmware updates or advanced diagnostics.

Preventative Care:

Annual Visual inspection: Conduct a yearly visual inspection of all optimizers and wiring for damage or corrosion.
Firmware Updates: Regularly update the SolarEdge inverter firmware to the latest version to ensure optimal performance and bug fixes.
String Performance Monitoring: Monitor string voltage and current on the SolarEdge monitoring portal to identify potential issues early.
Torque Verification: Periodically check the torque of all DC connections to prevent loosening over time.