How to Calculate the Battery Capacity Bank Size?


To calculate the battery capacity bank size, you need to consider the energy requirements of your system and the duration you want it to operate without recharging. The formula is:

Battery Capacity (Ah) = Total Load Power (W) \times \text{Operational Hours}}{\text{Battery Voltage (V)} \times \text{Depth of Discharge (DOD)}}

Make sure to convert all units to be consistent (e.g., watts to kilowatts, hours to ampere-hours). The depth of discharge is the percentage of the battery’s total capacity that can be used before recharging.

For example, if you have a 12V system with a total load of 300W, you want it to operate for 5 hours, and you allow a 50% depth of discharge:

[ \text{Battery Capacity (Ah)} = \frac{300 \times 5}{12 \times 0.5} ]

This formula gives you the required battery capacity in ampere-hours (Ah).