Convert battery capacity in Ah or mAh to power in kW or W using voltage and time, or find required capacity from power, voltage, and time.
Common Mistakes Quick tips
- Trying to convert Ah to kW without both voltage and duration; power needs energy ÷ time.
- Confusing energy with power: Ah × V = Wh (energy), not kW unless you divide by hours and by 1000.
- Missing unit scaling: mAh → Ah (÷1000), minutes → hours (÷60), seconds → hours (÷3600), kW ↔ W (×/÷1000).
- Assuming voltage stays constant; real battery voltage varies with load and state of charge.
When to Use This Calculator
- Estimate average power from a battery given capacity, voltage, and discharge time.
- Size a battery: compute required Ah to support a kW (or W) load for a target duration.
- Compare systems at different nominal voltages (12 V, 24 V, 48 V, etc.).
Input Definitions
- Battery Capacity — in Ah (or mAh); a measure of charge capacity.
- Power — average output over the chosen time, in kW or W.
- Voltage — nominal system voltage in V (or mV/kV).
- Time — discharge duration in hours, minutes, or seconds.
- Conversions — kW = (Ah × V) ÷ (t × 1000); Ah = (kW × 1000 × t) ÷ V; Energy: Wh = Ah × V; Current: A = Ah ÷ t.
- All Unit Converters
- Ah To Hours Calculator
- Ah to Kwh Conversion Calculator
- Ah to Watts Conversion Calculator
Ah to kW Formula
The following formulas convert amp-hours to kilowatts and back; use time in hours and voltage in volts.
\mathrm{kW} = \frac{\mathrm{Ah}\cdot V}{1000\, t_\mathrm{h}} \qquad \mathrm{Ah} = \frac{\mathrm{kW}\cdot 1000 \cdot t_\mathrm{h}}{V}- Ah = amp-hours (capacity), V = volts, th = time in hours; 1 kW = 1000 W.
- Energy: Wh = Ah × V; kWh = Wh ÷ 1000.
- Average current over the period: A = Ah ÷ th.
How do you convert Ah to kW? Multiply Ah by volts to get Wh, then divide by time (hours) and by 1000: kW = (Ah × V) ÷ (t × 1000).
How do you convert kW to Ah? Multiply kW by 1000 and by time (hours), then divide by volts: Ah = (kW × 1000 × t) ÷ V.
Ah to kW Conversion Table
| Capacity (Ah) | Power (kW) |
|---|---|
| 1 | 0.012 |
| 2 | 0.024 |
| 5 | 0.060 |
| 10 | 0.120 |
| 15 | 0.180 |
| 20 | 0.240 |
| 25 | 0.300 |
| 30 | 0.360 |
| 40 | 0.480 |
| 50 | 0.600 |
| 60 | 0.720 |
| 75 | 0.900 |
| 80 | 0.960 |
| 100 | 1.200 |
| 125 | 1.500 |
| 150 | 1.800 |
| 200 | 2.400 |
| 250 | 3.000 |
| 300 | 3.600 |
| 400 | 4.800 |
| * Using: kW = (Ah × V) ÷ (t × 1000). Table assumes V = 12 V and t = 1 h. | |
Example Problem
Convert 100 Ah at 24 V over 2 hours to kW.
Use the formula: kW = (Ah × V) ÷ (t × 1000).
kW = (100 × 24) ÷ (2 × 1000) = 1.2 kW
