Work-from-home backup guide
How long will a portable power station run a laptop?
A laptop charger shows its maximum output, not constant use. The most useful input is average wall power while doing the work you expect during the outage.
Backup power runtime
Estimate steady-load runtime after inverter losses and a safety reserve.
Runtime = capacity × efficiency × usable battery share ÷ average load. Motor surge, temperature, battery age and device cycling can change real-world runtime.
What changes the answer?
Charger rating is an upper bound
A 65-watt or 100-watt charger does not draw its full rating continuously. Screen brightness, processor load, battery charging and connected accessories change average demand.
Direct USB-C can avoid an AC conversion
When both devices support a compatible USB-C Power Delivery profile, direct DC output may reduce conversion losses. Confirm voltage, power and cable ratings before connecting.
Include the network if work depends on it
Add the modem, router and any display to a separate combined-load scenario. Laptop runtime alone does not keep an internet connection or external monitor running.
Use this result as a planning range
Use chargers and cables that meet the laptop and power-station specifications, and keep the battery equipment ventilated and dry.
Review the formulas and public sources in our methodology.
Official references
- Analyzing household electricity loadsU.S. Department of Energy
- Food safety during a power outageFoodSafety.gov
- Generator and carbon-monoxide safetyU.S. Consumer Product Safety Commission