Calculate the energy stored in a battery and its usable portion.
Energy is the product of charge and voltage, so a 100 Ah 12.8 V battery stores 1.28 kWh. Using nominal rather than peak voltage gives the realistic figure. Comparing batteries on amp-hours alone is misleading across different voltages; watt-hours is the only comparable unit.
Battery Energy
Energy (Wh) = capacity (Ah) × nominal voltage (V)
Energy (Wh) = capacity (Ah) × nominal voltage (V) Energy is the product of charge and voltage, so a 100 Ah 12.8 V battery stores 1.28 kWh. Using nominal rather than peak voltage gives the realistic figure.
Comparing batteries on amp-hours alone is misleading across different voltages; watt-hours is the only comparable unit.
This calculator takes 4 inputs: Capacity, Nominal voltage, Usable depth of discharge, Cells in series. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.