1. Core Compatibility: Three Electrical Parameter Matching Principles

　　Compatibility essentially refers to the electrical coordination between the PV panels, inverter, and battery system. Key parameters must meet the following conditions:

　　Voltage Matching

　　The operating voltage of the PV string must fall within the battery system's MPPT (maximum power point tracking) voltage range (typically 200-800V DC). Taking typical parameters as an example:

　　300W monocrystalline panel: Operating voltage ~30V, open-circuit voltage ~36V

　　Recommended number of panels in series: 18-22 (total voltage 540-660V)

　　400W monocrystalline panel: Operating voltage ~35V, open-circuit voltage ~42V

　　Recommended number of panels in series: 16-19 (total voltage 560-665V)

　　Note: Low temperatures will increase voltage, so a 10%-15% safety margin should be allowed to prevent overvoltage damage.

　　Current Matching

　　The total string current must be ≤ the maximum input current of the inverter (mainstream high-current inverters support 20A+). The short-circuit current of a single 300W panel is approximately 9.5A, and that of a 400W panel is approximately 11A. Limiting the number of parallel groups to 2-3 ensures current compliance.

　　Power Balance

　　The recommended total PV array power is 1.1-1.2 times the battery capacity (capacity-to-capacity ratio) to ensure full charging efficiency while avoiding overload. 20kW battery compatible total panel power:

　　300W panels: 67-80 panels (total power 20.1-24kW)

　　400W panels: 50-60 panels (total power 20-24kW)

　　II. Practical System Configuration

　　1. Typical Grid-Connected System Configuration

　　300W panels: Each panel has approximately 30V/10A parameters. It is recommended to connect 20 panels in series and 3 groups in parallel, for a total power of 18kW. The compatible inverter must meet MPPT requirements of 200-800V and an input current of 30A or higher. With this configuration, system efficiency can reach over 98%.

　　400W panels: Parameters for a single panel are approximately 35V/11.4A. A recommended configuration is 18 panels in series and three in parallel, for a total power of 21.6kW. The compatible inverter must meet MPPT requirements of 250-850V and an input current ≥34A.

　　2. Special Considerations for Off-Grid Systems

　　Off-grid systems require an additional charge-discharge controller (typically 60A/80A specifications) to support 300W/400W panel string voltages of 48V/96V. In a 48V system, 300W panels (30V) require two panels in series (total voltage 60V), while 400W panels (35V) require two panels in series (total voltage 70V). Both require a controller to step down the voltage to match the battery voltage.

　　3. Common Compatibility Scenarios

　　Most 20kW battery systems are compatible with high-efficiency panels around 320W and 400W. The recommended string configuration is 20 strings x 3 parallels. When paired with a compatible 400W dedicated inverter, system efficiency may increase by approximately 3%.

　　Some 20kW energy storage systems support mixed configurations of 300-450W panels. String parameters can be automatically detected via the relevant system app, and intelligent warnings will be triggered if the voltage deviates from the threshold (±5%).

　　Mainstream 20kW energy storage systems are typically labeled as compatible with 300W (common models) and 400W (common models) panels, requiring a total string power deviation of ≤10%. Some 410W/510W panels can also be directly compatible with 20kW batteries. The optimal configuration can be found using the inverter matching tool.

　　IV. Compatibility Pitfall Avoidance Guide

　　Avoid parameter mismatches: Prioritize checking the "maximum charging voltage" and "rated charging current" in the battery system manual. For example, if a 20kW battery has a maximum charge voltage of 750V/30A, no more than 21 400W panels can be connected in series (35V x 21 = 735V).

　　Prefer panels of the same specification: Mixing 300W and 400W panels can easily lead to power imbalance in the string. It is recommended to use panels of the same power model within the same system.

　　Verify inverter compatibility: Older inverters may not support high current input (e.g., ≤15A). Upgrade to a compatible model capable of 20A+ to avoid system operation impacted by insufficient current.

　　Verify standard parameters: When confirming compatibility, provide the battery parameters and panel model. Combine the configuration logic with the system manual to ensure that all component parameters match.

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