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Panasonic•EverVolt

Analysis by Marcus & Team

Panasonic EverVolt: Sulfur Smell During Charging

Diagnosing sulfur smell in Panasonic EverVolt battery during charging. Potential causes, safety measures, and professional solutions for residential energy storage.

Frequently Asked Questions

•What should I do if I see the EverVolt is overheating?

Immediately disconnect the system at both the AC and DC disconnects. Contact a certified technician.

•Where can I find a certified Panasonic EverVolt installer?

Consult the Panasonic website or contact their customer support for a list of qualified installers in your area.

•How often should the EverVolt system be inspected?

Annual inspections are recommended to ensure optimal performance and safety.

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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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Technical Overview:

The Panasonic EverVolt system utilizes lithium-ion battery modules managed by a Battery Management System (BMS). The BMS monitors cell voltages, temperature, and current to optimize performance and ensure safe operation. The DC voltage from the battery is converted to AC via an inverter for use in the home or export to the grid. Sulfur-like odors can arise from electrolyte decomposition or outgassing within the battery cells, potentially linked to overcharging, overheating, or manufacturing defects. Proper ventilation is critical to prevent the accumulation of flammable gases. Communication between the BMS and inverter ensures proper charging parameters are maintained, preventing conditions that could lead to off-gassing.

Technical Recommendation:

Access the EverVolt's internal diagnostic menu (consult the service manual for the specific key combination or software tool). Check the cell voltage deviation parameter. A deviation exceeding 0.2V between cells during charging or discharging indicates a potential cell imbalance or fault.

Common Causes:

Overcharging of battery cells due to BMS malfunction or incorrect charging parameters.
Internal short circuit within one or more battery cells, leading to electrolyte decomposition.
Electrolyte leakage due to cell damage or manufacturing defect.
Thermal runaway initiation in one or more cells, resulting in venting of decomposition products.
Degradation of separator material within the battery cells, leading to increased internal resistance and heat generation.
Hydrogen sulfide (H2S) or sulfur dioxide (SO2) release from failing cell components or contaminants.

Important Warnings:

Lithium-ion batteries contain high DC voltage, which can be lethal. A sulfur smell indicates a potential for thermal runaway and battery fire. Do not attempt to repair the system yourself. Contact a qualified electrician familiar with NEC Article 706 and energy storage systems. Ensure proper PPE, including safety glasses, gloves, and arc-rated clothing, is used during inspection. Observe all lockout/tagout procedures. Follow manufacturer's safety guidelines strictly.

Recommended Action:

1

Immediately disconnect the AC power supply to the EverVolt system at the main service panel. Follow NEC 706.15 guidelines for disconnecting energy storage systems.
2

Deactivate the DC disconnect switch located near the EverVolt unit. Verify voltage is near 0V with a calibrated multimeter before proceeding. Document DC bus voltage reading.
3

Contact a certified Panasonic EverVolt installer to inspect the system. Do not attempt to open the battery enclosure yourself.
4

The installer should use a calibrated multimeter and clamp meter to check individual cell voltages and module currents. Compare readings with the BMS data log.
5

The installer must use an IR thermometer to scan the battery enclosure for hotspots, indicating potential thermal runaway.
6

The installer should perform a diagnostic test using the Panasonic service software to check for error codes related to cell voltage imbalance, over-temperature, or communication faults. Analyze CAN bus data for anomalies.
7

If necessary, the installer should carefully remove the battery module and inspect it for signs of swelling, leakage, or corrosion in a well-ventilated area. Follow manufacturer-specific safety protocols.

Preventative Care:

Schedule annual inspections by a certified technician to check for signs of degradation or damage. Ensure proper torque on all electrical connections.
Monitor the EverVolt system's performance data regularly via the monitoring app, paying attention to cell voltages, temperatures, and charging/discharging currents. Check SOC and SOH regularly.
Keep the battery enclosure clean and free of debris to ensure proper ventilation. Clean with a dry cloth only; avoid liquids.
Ensure the system firmware is up to date to address potential bugs or improve performance. Enable automatic firmware updates if available.
Periodically perform a full charge/discharge cycle to help balance the cells and maintain capacity. Log all test data.