Published September 13, 2026 · Reserve Current editorial guide · Updated September 24, 2026
Quick answer: Three numbers answer different questions. Average watts estimate how long a battery lasts. Running watts must stay within the station's continuous rating. Starting (surge) power decides whether motors and compressors can start at all. Check all three, then test with the real appliance.
Average watts estimate energy
Time-averaged power is useful for estimating battery duration. An appliance that cycles on and off can have a low average even when its demand while operating is much higher. Feeding only the average into a power-compatibility check can produce a misleading answer.
Running watts check sustained demand
Check the demand while equipment is actually operating, and add other devices that may run simultaneously. Compare that total with the station’s normal continuous rating and the limits of individual outlets. Do not count a special boost-mode number as normal output without checking how it works.
Starting power is a separate limit
Motors and compressors may demand more power while starting. Surge capability is not described completely by one large number: duration, voltage behavior and the appliance’s requirements matter too. The manufacturer’s guidance and an appropriate test with the actual equipment are more useful than a generic compatibility promise.
Keep the two decisions separate
The calculator estimates energy duration. It warns when even the average load exceeds the entered continuous rating, but it cannot certify compatibility. Before relying on the setup, confirm running and starting requirements, then test operation according to the manuals while another power source is available.
Check a specific appliance and station with the Will it run? checker.
Frequently asked questions
What is the difference between running watts and starting watts?
Running watts are what a device draws while operating; starting watts are the brief extra demand of a motor or compressor when it starts. The station's continuous rating must cover the first, its surge capability the second.
Can I use a power station's boost mode for any appliance?
Do not count a special boost-mode number as normal output without checking how it works for your appliance. Some modes reduce voltage to keep resistive loads running and are not equivalent to full continuous output.