Power station runtime calculator

Estimate how long a portable power station could run a stated load. Start with usable battery energy and measured running power for the equipment you want to connect. The battery capacity alone cannot tell you runtime.

Collect usable energy in watt-hours, conversion efficiency, connected running watts and the power used by the inverter while on. The inverter converts stored battery energy to the output your equipment uses. Keep its idle use separate if it is not already included in your load measurement.

Also collect the power station continuous and starting-output limits. Running power and starting demand are different checks. Some equipment briefly needs more power when it starts than while it keeps running.

Available output energy Wh = usable stored Wh × conversion efficiency. Estimated runtime hours = available output Wh ÷ (connected running watts + inverter idle watts). Check continuous and starting power against entered output limits.

Use a percentage as a fraction once: for example, 50% means 50 ÷ 100 = 0.5. Use 0.5 in the energy formula; do not divide it by 100 again.

Stored energy is entered in watt-hours and operating load in watts. Apply the conversion efficiency to the usable stored energy, then divide by the running load plus separately entered inverter idle consumption. Do not deduct a conversion loss twice if the documented usable energy already represents delivered output. Continuous output and supported starting output are separate equipment ratings.

Read the power-limit checks as well as runtime. A long energy-based estimate does not mean the power station can start or support the connected equipment. Use the combined demand of items that could start together, rather than checking each item alone.

These illustrative inputs are separate from your saved answers. Prices, use and performance are held constant for this worked scenario; they are not personal defaults.

Do not apply conversion losses twice to a maker capacity that already represents delivered AC energy. Use matching documentation.

Runtime varies with load, standby use, battery condition and temperature. Starting demand and continuous ratings require a separate equipment check.

The calculation assumes the entered running load stays constant. Equipment that cycles needs a suitable average for runtime, but its full running and starting needs still require the separate power check. A brief meter sample may not describe the intended use.

Use watt-hours for energy and watts for power. A capacity quoted in another unit must be converted before entry. Do not substitute a nominal rating for usable energy without checking what the maker includes.

The result is an estimate for the entered setup. It does not test the battery, model recharging during use or guarantee supply for an essential load. Keep a record of the equipment and measurements. Invalid edits retain the last valid result with a warning.

The UK and Australian versions use the stated equipment units rather than a fuel tariff. Source dates describe the stored method; they do not verify your battery or connected appliances.

Use the exact model documents and output ratings for your local equipment. A product name or family rating may not describe every version. The calculator does not check plugs, voltage, installation rules or compatibility. Confirm those separately with the maker or a qualified local professional.

Ask the maker or a qualified electrical professional if you are unsure about usable capacity, output limits or starting demand. Bring a full equipment list and the power station manual.

Use an appropriate qualified professional for any connection to building wiring. Follow the maker instructions. This runtime estimate does not approve an installation or establish a dependable backup arrangement for essential equipment.