How to size battery for solar panel
- Determine the total Watt-Hours/day consumed by appliances.
- Divide the total Watt-Hours/day consumed by the battery loss factor (typically, it is 0.85).
- Divide the answer you got in item 2 by the depth of discharge of battery (typically it is 0.6).
- Divide the answer you got in item 3 by the Nominal Battery Voltage.
- Multiply the answer you got in item 4 with days of autonomy (the number of days required for the system to operate by solar panels when there is no power generated) to get the required capacity of the deep-cycle battery in Ampere-Hour (AH).
Battery Capacity (AH) = (Total Watt-Hours/day consumed by appliances x days of autonomy)
(battery loss factor x depth of discharge x nominal battery voltage)