Quick Answer
To size solar arrays with Tesla battery modules, consider the total energy required, the battery's capacity, and the solar panel's efficiency. A general rule of thumb is to size the solar array to 150-200% of the battery's capacity to ensure adequate charging. This calculation should be based on peak sun hours and local irradiance.
Understanding Tesla Battery Module Capacity
When sizing solar arrays with Tesla battery modules, it’s essential to understand the capacity of the battery. Tesla’s Powerwall 2, for example, comes in 13.5 kWh and 9.6 kWh capacities. The 13.5 kWh model has a maximum charge rate of 11.4 kW and a maximum discharge rate of 9 kW. The 9.6 kWh model has a maximum charge rate of 8.4 kW and a maximum discharge rate of 7.2 kW.
Calculating Solar Array Size
To calculate the required solar array size, first determine the total energy required from the battery. Let’s assume you have a 13.5 kWh Powerwall 2 and you want to charge it from 20% to 80% every day. This is approximately 10.8 kWh per day. Next, calculate the required solar panel capacity. Assuming a 20% loss in solar panel efficiency due to inverter losses and wiring, you would need a solar array that can produce 16.4 kWh per day (10.8 kWh / 0.65). Based on an average of 5 peak sun hours (PSH) per day, you would need a solar array of approximately 3,280 watts (16.4 kWh / 5 PSH).
Additional Considerations
When sizing solar arrays with Tesla battery modules, consider additional factors such as local irradiance, seasonal sun angle changes, and inverter efficiency. Always consult Tesla’s sizing guidelines and local building codes to ensure compliance. It’s also essential to account for any shading issues or obstructions that may impact solar panel efficiency.
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