Battery Energy Calculator
Calculate battery energy in Wh and kWh from voltage and amp-hours.
Estimate runtime at a given load.
Battery Energy
Battery energy calculations:
Energy (Wh) = Voltage (V) × Capacity (Ah)
Energy (kWh) = Wh / 1000
Runtime (hours) = Wh / Load (watts)
Common battery voltages:
- AA/AAA: 1.5V (alkaline) / 1.2V (NiMH)
- 18650 Li-ion: 3.7V nominal
- Car battery: 12V
- Power station: 12–48V
- EV battery: 300–800V
Capacity examples:
| Battery | Voltage | Ah | Wh |
|---|---|---|---|
| AA NiMH | 1.2V | 2.5 Ah | 3 Wh |
| 18650 Li-ion | 3.7V | 3.5 Ah | 13 Wh |
| Car battery | 12V | 60 Ah | 720 Wh |
| Tesla Powerwall | 48V | 28 Ah | 13,500 Wh |
Note: Actual runtime is typically 80–90% of calculated due to efficiency losses and minimum voltage cutoff.