Quick Answer
To calculate the right number of solar panels needed, multiply your hourly energy requirement by the number of peak sun hours your location receives, and then divide by the wattage of each panel. For a level 2 charger, a typical daily energy requirement is around 16-32 kWh. Use a solar panel wattage of 350-400 watts per panel for a conservative estimate.
Determining Hourly Energy Requirement
To calculate your hourly energy requirement, divide your daily energy requirement by 24. For a level 2 charger, this would be 16-32 kWh / 24 hours = 0.67-1.33 kWh per hour. Make sure to account for any additional energy requirements, such as lighting or water pumping systems.
Calculating Solar Panel Requirements
Assuming a peak sun hour (PSH) of 5 hours per day for your location, you’ll need to calculate how many solar panels are required to meet your hourly energy requirement. Using our previous calculation, 0.67-1.33 kWh per hour, you’ll need 1-2 kilowatts (kW) of solar power. Convert this to wattage by multiplying by 1,000 (1 kW = 1,000 watts), resulting in 1,000-2,000 watts. Divide this number by the wattage of each solar panel (350-400 watts per panel) to determine the total number of panels needed. For our example, 1,000-2,000 watts / 350-400 watts per panel = 2.5-5 panels.
Accounting for Charger Efficiency
When sizing your solar panel system, don’t forget to account for the efficiency of your level 2 charger. A typical level 2 charger has an efficiency of around 80-90%, meaning it can only utilize 80-90% of the energy generated by your solar panels. To account for this, increase your total wattage requirement by 10-20% to ensure you have enough energy to meet your needs.
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