Motor and compressor startup
Check the startup gate before calculating runtime.
Running watts determine sustained output. Starting watts test a separate peak-output gate. This tool keeps voltage, continuous load, and published peak evidence distinct.
Startup check
Compare the appliance with the inverter
Use measured inrush or model-specific startup evidence. Do not substitute a resistive-load boost mode for a general motor surge rating.
Published ratings clear these inputs
- Voltage
- Pass
- Continuous output
- Pass
- Published peak
- Pass
Why a peak-watt number is not the whole answer
Startup has both magnitude and duration. A station can advertise a high peak yet shut down before a motor reaches speed. A compressor can also behave differently against pressure than it does during an easy restart.
Confirm voltage first, then continuous output, then model-specific starting demand against a documented station peak and duration. Hardwired loads need an approved transfer method.
Running watts and starting watts test different limits
Continuous output covers the appliance after it reaches normal operation. Starting demand can be several times higher for a compressor, pump, or blower motor. The station has to clear both gates at the correct voltage before stored energy becomes relevant.
A published peak number is incomplete without duration. The motor may need enough time to accelerate, and a compressor can start harder when pressure has not equalized. Resistive-load boost modes can lower voltage to support some heaters or kettles, but they are not general motor-start ratings.
Measure startup when the consequence matters
Use an inrush-capable meter, a manufacturer startup specification, or a model-specific compatibility record. Ordinary plug-in meters may miss a brief peak. Pumps, refrigeration, furnaces, and hardwired equipment also need the correct connection method and protection.
After startup is resolved, use the runtime calculator for one appliance or the outage load planner for several loads. The 120V versus 240V guide explains why voltage cannot be repaired with extra battery capacity.