Inverter Charging Settings: A Master Guide for Axpert, Deye, Growatt, and Solis Systems

Key Takeaways

• Always consult your inverter and battery manuals for precise charging voltage and current settings.
• Battery chemistry (flooded, AGM, Gel, Li-ion) dictates the specific voltage and current requirements.
• Incorrect settings can damage batteries, reduce their lifespan, or cause system malfunctions.
• If you are unsure about any setting or encounter persistent issues, stop and contact a qualified technician.

Understanding Inverter Charging Settings

Properly configuring your inverter's charging settings is crucial for the health and longevity of your battery bank. These settings determine how your inverter charges your batteries from solar panels or the grid. Key parameters include bulk charging voltage, floating charging voltage, equalization voltage, and low DC cut-off voltage. For lithium-ion batteries, State of Charge (SOC) settings are also critical.

Different battery chemistries require distinct charging profiles. Lead-acid batteries (flooded, AGM, Gel) typically use voltage-based charging stages, while lithium-ion batteries often rely on their internal Battery Management System (BMS) to dictate charging parameters, especially when communication protocols (CAN, RS485) are established.

Axpert VM III Charging Settings

The Axpert VM III inverter/charger offers configurable settings for various battery chemistries. It is important to match these settings to your specific battery type and system voltage (24Vdc or 48Vdc).

Safety Note for Equalization: Equalization charging drives lead-acid cells into the hydrogen gassing region. Always ensure the battery area is well-ventilated and free from sparks or flames during this process.

Growatt SPF 5000 ES Charging Settings

Growatt SPF 5000 ES inverters offer specific settings for both lead-acid and lithium batteries. For lithium batteries, State of Charge (SOC) based settings are used in addition to voltage parameters.

For lithium batteries without communication, the Growatt SPF 5000 ES manual advises checking if the voltage points of Program 19 and 21 are too high if a "Bus voltage is too high" (Fault code 08) or "Battery connection is open" (Fault code 56) error occurs.

Deye SG03LP1 Battery Settings

Deye SG03LP1 inverters (models SUN-3.6K-SG03LP1-EU, SUN-5K-SG03LP1-EU, SUN-6K-SG03LP1-EU) provide a battery voltage range for both lead-acid and lithium-ion chemistries.

For Li-ion batteries, the Deye SG03LP1 inverter features self-adaption to the Battery Management System (BMS). This means the inverter communicates with the battery's BMS to determine optimal charging and discharging parameters. If a "BMS communication fault" (F66) occurs, the inverter may stop charging or discharging. You can disable the BMS_Err_Stop item on the LCD if you do not want this behavior, but it is generally recommended to resolve communication issues.

Solis S5-EH1P Battery Settings

Solis S5-EH1P inverters support both Li-ion and lead-acid batteries. The manual provides specific parameters for each chemistry.

Lead-acid Battery Settings (Solis S5-EH1P)

Temperature Compensation: The Solis S5-EH1P manual specifies a temperature compensation of 072mV/degC for lead-acid batteries. This value adjusts charging voltages based on ambient temperature to prevent over or undercharging. The ambient temperature upper limit is +45degC and the lower limit is +05degC.

Li-ion Battery Settings (Solis S5-EH1P)

The Solis S5-EH1P inverter has a general battery voltage range of 42 - 58V and supports battery capacities from 50 - 2000Ah for both Li-ion and lead-acid.

GoodWe ET Battery Settings

GoodWe ET hybrid inverters (e.g., GW5KL-ET, GW6KL-ET, GW8KL-ET, GW10KL-ET) are designed for Li-Ion batteries and provide a nominal voltage and operational range.

The GoodWe ET inverter prioritizes PV energy to loads, then excess to the battery. When the battery is full, excess is exported to the grid. If the battery is insufficient, the system draws power from the grid.

Pylontech US3000C Battery Specifications

While the Pylontech US3000C is a battery and not an inverter, its specifications are critical for setting compatible inverter charge parameters. This battery features a built-in BMS that manages and monitors cells.

When pairing a Pylontech US3000C battery with an inverter, ensure the inverter's charge voltage and current settings fall within the battery's specified ranges. The Pylontech US3000C manual states that if the charging voltage is above 54V, battery protection will activate. Similarly, if the battery discharges to 44.5V or less, battery protection will turn on.

Battery Cable Sizing Recommendations

Proper battery cable sizing is essential to minimize voltage drop and ensure safe current flow. Undersized cables can lead to energy loss, overheating, and potential fire hazards.

For Pylontech US3000C, the power cables (4 AWG) have a peak current capacity of 120A and a constant capacity of 100A. Grounding cables should be 10AWG or higher yellow-green cables. You can find more information on sizing cables for solar systems at /pk/tools.

Safety Considerations for Battery Charging

Working with batteries and inverters involves electrical and chemical hazards. Always prioritize safety.

• Qualified Personnel: Only qualified personnel should install and maintain these devices with batteries.
• Frozen Batteries: Never attempt to charge a frozen battery. This can cause severe damage or explosion.
• Metal Tools: Be extremely cautious when working with metal tools around batteries. A dropped tool can cause a spark or short circuit, leading to an explosion. Use insulated tools where possible.
• Grounding: Inverters should be connected to a permanent grounded wiring system. For Pylontech US3000C batteries, the battery must connect to ground, and the resistance must be less than 0.1Ω.
• Polarity: Before making final DC connections, ensure positive (+) is connected to positive (+) and negative (-) to negative (-). Reverse polarity connection will damage the inverter.
• Ventilation: For lead-acid batteries, especially during bulk or equalization charging, ensure the area is well-ventilated to disperse hydrogen gas.
• Eye Protection: When working with lead-acid batteries, wear eye protection to guard against acid splashes.
• Disconnection: Before any wiring connections or electrical operations, disconnect all DC and AC power from the inverter. Wait at least 5 minutes for capacitors to discharge before touching internal components.
• Temperature: The surface temperature of inverters can exceed 60℃ (140°F) or even 75℃ (167°F) during operation. Avoid touching the inverter's surface while it is running to prevent burns.
• Lithium Batteries: Do not connect lithium batteries in series. The embedded BMS in Pylontech US3000C batteries is designed for 48VDC. It is prohibited to connect batteries of different types or with faulty/incompatible inverters.
• Fire Safety: In case of a battery fire, only use a dry powder fire extinguisher. Liquid fire extinguishers are prohibited.

When to Consult a Professional

While many charging settings can be adjusted by the user, some situations require professional intervention:

• Persistent Errors: If your inverter displays fault codes that you cannot resolve using the manual's troubleshooting steps, such as "Battery is over-charged" (Axpert VM III code 03, Growatt SPF 5000 ES code 03) or "BMS communication fault" (Deye SG03LP1 F66).
• Unusual Behavior: If the system exhibits unexpected behavior, such as repeated shutdowns, unusual noises, or inconsistent charging.
• BMS Issues: For lithium battery systems, if there are indications of BMS failure or communication loss, a technician can diagnose and resolve complex issues.
• Warranty Concerns: Attempting repairs or modifications beyond the scope of the user manual may void your product warranty.
• Complex System Expansion: When adding more batteries or integrating new components, a professional can ensure proper sizing, wiring, and configuration.
• Safety Concerns: If you are ever unsure about the safety of an operation or feel uncomfortable performing a task, stop and call a qualified solar technician.