Surge Watts vs Running Watts: Why Startup Power Matters
Surge watts are the brief spike when a motor starts. Running watts are the steady-state draw. Here's why ignoring surge can brick your setup.
The Short Answer
Running watts are the continuous power a device draws during normal operation. Surge watts (also called startup watts or peak watts) are the brief spike — usually lasting under a second — when a motor or compressor first kicks on. A refrigerator might run at 150W but surge to 800W on startup. Your power station must handle the surge, or it'll trip the overload protection and shut off.
Which Devices Surge?
Anything with a motor or compressor: refrigerators, freezers, air conditioners, power tools, pumps, and fans. The surge is typically 2-4x the running watts for compressor-driven devices and 1.3-2x for motor-driven devices. Electronics without motors (laptops, phones, routers, TVs, LED lights) have little to no surge.
Why This Matters for Power Stations
Every portable power station has two power ratings: continuous watts and surge (peak) watts. The continuous rating is what it can sustain indefinitely. The surge rating is what it can handle for a fraction of a second. If your fridge surges at 800W, you need a station with at least 800W surge capacity — even if the fridge only runs at 150W continuously.
A Common Mistake
Buying a 500W power station because your fridge "only uses 150W." When the compressor kicks on, the 800W surge trips the station's overload protection. The station shuts off. The fridge stops. You're left wondering what went wrong. Always check the surge requirement, not just the running wattage.
How to Check
Look for the "LRA" (Locked Rotor Amps) or startup wattage on the device's nameplate or manual. If it's not listed, assume 3x running watts for compressor devices and 1.5x for motor devices. When in doubt, oversize. A station with 2000W surge can handle virtually any single household appliance startup.