Quick Answer
For a 24-hour battery bank, a solar panel size of 400-600 watts is recommended to recharge the battery bank during the day and maintain a full state of charge.
Battery Bank Sizing
When sizing a solar panel array for a 24-hour battery bank, it’s essential to consider the total daily energy demand. This includes the energy consumption of all appliances, lighting, and other loads during a 24-hour period. A general rule of thumb is to size the solar panel array to recharge the battery bank within 24 hours, considering a 20% to 30% reserve capacity for safety and flexibility.
Calculating Daily Energy Demand
To calculate the daily energy demand, add up the total watt-hours (Wh) of all appliances, lights, and other loads. For example, if a household has a refrigerator using 150 Wh/h, a laptop using 30 Wh/h, and LED lights using 20 Wh/h, the total daily energy demand would be 200 Wh/h. To calculate the daily energy demand in watt-hours (Wh), multiply the total daily energy demand in watt-hours per hour (Wh/h) by 24 hours: 200 Wh/h * 24 h = 4800 Wh.
Solar Panel Array Sizing
When sizing the solar panel array, consider the maximum power point tracking (MPPT) efficiency and the solar panel’s peak power rating. A 400-watt solar panel with an MPPT efficiency of 95% can produce approximately 380 watts of usable power. To recharge the battery bank within 24 hours, the solar panel array should produce enough power to cover the daily energy demand, considering the battery bank’s capacity and the desired depth of discharge (DOD). For a 24-hour battery bank, a solar panel size of 400-600 watts is recommended to recharge the battery bank during the day and maintain a full state of charge.
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