Power Station Runtime Calculator
Enter the battery capacity and the load to see how many hours you will get.
Add a device (typical power)
How it is calculated
Runtime = capacity × efficiency ÷ load
Generator runtime = fuel in tank ÷ hourly consumption
Notation
- capacity
- battery capacity, Wh
- efficiency
- inverter efficiency as a fraction
- load
- total power of the devices, W
Worked example
- Station 1,000 Wh, efficiency 85%, load 100 W.
- 1,000 × 0.85 = 850 Wh of usable energy.
- 850 ÷ 100 = 8.5 hours, or 8 h 30 min.
Capacity on the box is not the energy you get: the inverter loses part of it while converting battery power to mains voltage. The calculator takes this into account, and the device buttons help you add up a realistic load.
For a generator the logic is simpler: tank volume divided by hourly consumption. Use the figure from the manual for your expected load.
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How long will a 1000 Wh power station run?
With a 100 W load and 85% inverter efficiency, about 8 hours 30 minutes: 1,000 × 0.85 ÷ 100 = 8.5. At 500 W the same station lasts about 1 hour 42 minutes.
Why is the real runtime shorter than capacity divided by load?
The inverter loses energy when it converts battery power to 230 V, usually around 10–20%. Cold temperatures and an old battery reduce it further.
Can a power station run a fridge?
Usually yes, if its output exceeds the fridge's start-up power, which is several times the running power. The compressor also cycles on and off, so the average load is below the rated power on the label.
How do I find a generator's runtime?
Divide the fuel in the tank by the hourly consumption from the manual. A 15 L tank at 1.2 L/h lasts 12.5 hours.
What does efficiency mean here?
It is the share of battery energy that reaches your devices. We use 85% by default; replace it with the figure from your model's specifications if you have one.