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SolarEdge•Unknown

Analysis by Marcus & Team

SolarEdge Battery Losing Charge Overnight: Diagnosis

Diagnosing SolarEdge battery overnight charge loss. Find possible causes, solutions, and safety tips for your residential energy storage system.

Frequently Asked Questions

•What is the expected lifespan of a SolarEdge battery?

The lifespan of a SolarEdge battery typically ranges from 7 to 10 years, depending on usage patterns, operating temperature, and maintenance practices.

•How often should the BMS be calibrated?

The BMS calibration frequency depends on the specific model and usage. Generally, a calibration every 1-2 years or after significant changes in usage patterns is recommended.

•What are the optimal operating temperature ranges for a SolarEdge battery?

Optimal operating temperature ranges for SolarEdge batteries are typically between 15°C to 30°C (59°F to 86°F). Extreme temperatures can negatively impact performance and lifespan.

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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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Critical Safety Precautions:

SolarEdge battery systems operate at high DC voltages, posing a significant electrical shock hazard. Never attempt to work on live circuits. Always disconnect AC and DC power sources before performing any maintenance or troubleshooting. Adhere to NEC rapid shutdown procedures. Consult a qualified electrician for all repairs and maintenance.

Solution:

1

Disconnect the AC power to the SolarEdge inverter and battery system following NEC rapid shutdown procedures. Verify zero voltage at the AC disconnect.
2

Use a calibrated multimeter to measure the DC bus voltage of the battery system. Compare this reading to the expected voltage range specified in the SolarEdge documentation.
3

Use a DC clamp meter to measure the standby current draw of the inverter and BMS. Excessive current draw indicates potential component failure or parasitic loads. Consult SolarEdge documentation for acceptable ranges.
4

Perform a battery capacity test using the SolarEdge monitoring portal (if available) or through a qualified technician with specialized battery testing equipment to assess the actual battery capacity and State of Health (SOH).
5

Inspect battery connections for corrosion or loose wiring. Clean and tighten connections as necessary. Use an antioxidant compound on connections.
6

Review the inverter and BMS firmware versions. Update to the latest versions through the SolarEdge monitoring portal or app. This can resolve software glitches contributing to charge loss.
7

If SOC reporting is suspected, perform a full charge and discharge cycle and recalibrate the BMS according to the manufacturer's instructions. A qualified technician might be required.

Observed Symptoms:

The SolarEdge battery system is exhibiting a 5% State of Charge (SOC) decrease overnight under zero load conditions.

Possible Causes:

Parasitic loads from the inverter, BMS, or other system components consuming power even when no load is present.
Self-discharge of the lithium-ion or LFP battery cells. The rate increases with temperature and age.
BMS calibration errors leading to inaccurate SOC reporting. The BMS may be overestimating the SOC initially.
Internal resistance increase in battery cells, leading to higher heat generation and energy loss.
DC-DC converter inefficiency during idle or standby mode, causing slight drain.
Software glitches or firmware bugs within the BMS or inverter control logic.

Technical Background:

Residential SolarEdge battery systems typically consist of lithium-ion or LFP battery modules, a Battery Management System (BMS), a DC-DC converter for voltage regulation, and an inverter for DC-AC conversion. The BMS monitors cell voltages, temperature, and current to optimize performance and ensure safety. Standby power consumption by the inverter and BMS, parasitic loads, and self-discharge of the battery cells themselves can contribute to overnight charge loss. Inefficient DC-DC conversion can also result in losses during idle states. Grid support functions that draw minimal power are also relevant.

Prevention:

Regularly check the SolarEdge monitoring portal for error codes or abnormal battery behavior.
Keep the battery system clean and free of dust or debris. Ensure proper ventilation to prevent overheating.
Schedule annual licensed technician inspections of the battery system to assess battery health, connection integrity, and firmware versions.
Perform periodic battery capacity tests to track State of Health (SOH) and identify potential degradation.
Ensure proper thermal management by verifying ambient temperature is within the manufacturer's recommended range. Optimize ventilation if needed.