Portable Power Station Runtime Calculator
Estimate how long a portable power station can run your devices based on battery capacity, load wattage, and inverter efficiency.
Calculate runtime
Enter battery capacity, device load, and efficiency to estimate total runtime.
8.70 hours
How long will a power station last?
Runtime depends on battery size and power draw.
- Small loads (phones, routers): many hours
- Medium loads (laptops, lights): several hours
- High loads (heaters, kettles): very short runtime
Tips for success
- Rated capacity is usable capacity. Most portable stations already account for inverter loss in their spec.
- Pass-through charging. Stations with pass-through charging let you run loads while recharging from solar or wall.
- LiFePO4 lasts longer. Lithium (LiFePO4) stations keep 80% capacity after 2,500+ cycles; older Li-ion types fade faster.
- Burst-use for high-draw devices. High-draw devices (microwaves, kettles, hair dryers) drain a station in minutes; plan for short bursts only.
Runtime assumes continuous draw at the load's rated wattage. Most real appliances pull less on average (compressors cycle, laptops idle), so observed runtime often exceeds the calculated worst case by 20–40%. For preparedness planning, always size with a safety margin and verify with a real test run before a live emergency.
Common mistakes
- Ignoring efficiency losses. Real stations lose 10–30% of rated capacity to inverter and conversion losses.
- Using peak wattage instead of average. Most appliances draw far less than their peak rating under normal use.
- Overestimating usable battery capacity. Older or partially degraded batteries have less usable capacity than the label suggests.
- No real-world test. Run a 1-hour test with your actual devices before an emergency to know your actual numbers.
- No recharge plan. Have a solar panel or wall outlet schedule ready; a power station without a recharge plan is a single-use item.
FAQ
Why include efficiency?
Energy is lost through conversion and inverter use.
Can this replace a generator?
For small loads yes, but not for high-power appliances.
How long will a portable power station last in a real outage?
For a 1,000 Wh power station running a fridge (150 W average), laptop (40 W), and some LED lights (20 W), you'll get roughly 4 to 6 hours before needing to recharge. A 2,000 Wh unit stretches that to 8 to 12 hours. For multi-day outages, pair the power station with solar panels to recharge during daylight, even a 100-watt panel adds 300 to 500 Wh per sunny day.
What's the difference between Wh and Ah on a power station?
Wh (watt-hours) is the number that matters, it directly tells you how long a device will run. Ah alone isn't useful without knowing the voltage. A 1,000 Wh unit runs a 100-watt device for about 10 hours (minus efficiency loss). Always compare power stations by Wh capacity, not by Ah or by the headline 'continuous watts' output rating, which describes peak power, not total energy.
Can I charge the power station while running devices off it?
Yes for most modern units, a feature called 'pass-through charging.' The input AC or solar power flows through to power the loads and top off the battery simultaneously. Check your unit's spec, some older or cheaper models only charge when loads are disconnected, and a few can't pass through more wattage than the input rating. Pass-through is valuable in extended outages when solar is your only recharge source.