Power Energy
Battery Energy
Battery energy is estimated by multiplying nominal voltage by capacity in ampere-hours. The result is in watt-hours; divide by 1000 for kilowatt-hours. This is a nominal figure: the usable energy is always lower because of internal resistance, voltage sag, temperature and the depth of discharge the system allows.
Battery Energy
E = V × Ah
Variables and units
| Symbol | Quantity | Unit |
|---|---|---|
| E | Nominal energy | Wh |
| V | Nominal battery voltage | V |
| Ah | Battery capacity | Ah |
Conditions of application
Nominal estimate at the stated voltage and capacity. Usable energy is lower and depends on discharge rate, temperature, age and the depth of discharge permitted by the system.
Worked example
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Convert amp-hours and voltage to watt-hours and kilowatt-hours.