Quick answer
Runtime depends on usable watt-hours, inverter losses, the actual load, temperature, battery age, and whether the device runs continuously or cycles on and off. This calculator gives you a planning range — not a guarantee.
Use the appliance presets for common devices, or enter custom values if you know the exact load. A watt-meter reading is more accurate than guessing from a spec sheet.
Calculator
Estimate power station runtime
This runs in your browser. No data leaves the page.
Presets set load and duty cycle. Switch to Custom to enter your own numbers.
10% is a common planning reserve to avoid fully draining the battery.
Continuous = 100%. Cycling appliances like fridges typically run 25–50% of the time.
Usable energy
783 Wh
After efficiency and reserve
Average load
60 W
100% duty cycle
Estimated runtime range
10.4 hours to 14.4 hours
Conservative to optimistic. These are planning estimates, not guarantees.
Base estimate
13.1 hours
How the calculator works
The formula is straightforward:
- Usable watt-hours = battery Wh × efficiency × (1 − reserve fraction)
- Average load = load watts × (duty cycle ÷ 100)
- Estimated hours = usable Wh ÷ average load
The result is shown as a range: the base estimate, a conservative estimate at 80% of the calculated number, and an optimistic estimate at 110%. Real-world conditions fall somewhere in between.
What affects runtime
- Inverter efficiency — converting DC battery power to AC household power loses 10–25% depending on the inverter quality and load.
- Battery age and temperature — cold reduces usable capacity. Older batteries lose capacity over time.
- Duty cycle — a fridge that cycles on 5 minutes per 15 minutes runs at a 33% duty cycle, not 100%.
- Reserve margin — most batteries should not be fully drained. The calculator defaults to 10% reserve to protect battery life.
- Starting surge — fridges, pumps, and motors draw 2–5x their running watts for a split second when starting. The inverter must handle that peak.
What portable power stations are good for
- Wi-Fi routers, modems, and network gear
- Phone, tablet, and laptop charging
- LED lighting
- CPAP and medical devices (with manufacturer confirmation)
- Small electronics and entertainment
- Intermittent appliance use (mini-fridge, fan, air purifier)
What they are not great for
- Resistive heat loads (space heaters, kettles, toasters, hair dryers) — they drain most stations in under an hour.
- Large motor loads (well pumps, large fridges, freezers, furnace fans) — starting surge may exceed inverter limits.
- Whole-home backup — that needs a generator or a much larger battery system installed by a licensed electrician.
Official sources used
Public Safety Canada / Canada.ca
Canadian household outage risks and 72-hour preparedness framing.
Health Canada
Recognized Canadian certification marks and electrical product warnings.
Buying electrical products online
Health Canada
Risks of uncertified electrical products from online marketplaces.