Most portable power station reviews answer a simple question: how many watts does it produce? That number matters, but it only tells half the story. The other half, the half that determines whether your refrigerator actually starts at 2 AM during a blackout, is surge.
Every motor-driven device in your home draws far more power at the instant it turns on than it does while running. Your refrigerator compressor might cruise at 200 watts, but the fraction of a second it takes to spin the motor from a dead stop can demand 400 to 600 watts. An air compressor can spike to five times its running load. If your power station’s inverter cannot absorb that spike, it shuts down to protect itself, and your food starts warming up.
That gap between marketing claims and electrical reality is what GeneratorChecker exists to close. Our compatibility engine, the True Surge Protocol, evaluates every generator-device pairing in our database using three things: device-specific OEM data, NEC electrical standards, and conservative load-profile buffers that account for the conditions marketing materials conveniently ignore.
This page explains exactly how that engine works, where the numbers come from, and where we draw the line on what we can and cannot claim.
The Three-Gate Compatibility Check
We check whether the power station delivers the right voltage, whether it can handle the device’s startup spike, and whether it can sustain the running load long enough to matter. Each pairing runs through three sequential gates. If it fails at any gate, the process stops and returns a verdict. The one exception: when a device fails the surge gate, our engine also evaluates whether a soft-start device could reduce the startup spike enough to bring it within range. If it can, the verdict is SOFT_START rather than FAIL.
Gate 1: Voltage
This is a hard pass/fail. The power station either outputs the voltage the device requires, or it does not.
Most portable power stations output 120V only. That works for the majority of household devices. But four categories of devices in our database require 240V: central air conditioners, well pumps, electric water heaters, and clothes dryers. If a 120V-only power station is paired with any of these, the result is an automatic VOLTAGE_FAIL. No amount of wattage compensates for a voltage mismatch.
Gate 2: Surge
This is where most pairings succeed or fail in practice. Can the power station’s peak output handle the device’s startup spike?
The startup demand of a motor-driven device is dramatically higher than its running demand. How much higher depends on the device. A few examples from our database, all pulled from OEM-published specifications:
CRAFTSMAN CMEC6150 (pancake air compressor) runs at 1,320W but surges to 6,800W at startup: a 5.15-to-1 ratio. Those numbers come directly from CRAFTSMAN’s support documentation, not from a generic “air compressor” estimate.
Frigidaire FHWC084WB1 (8,000 BTU window AC, standard compressor) runs at 670W. Its estimated startup demand is approximately 2,010W, roughly 3 times the running load. This is a non-inverter unit with a single-speed compressor, and the 3x multiplier reflects standard engineering estimates for this motor type.
LG LMXS28596S (French door refrigerator) runs at approximately 207W. We estimate its startup surge at 414W using a conservative 2x multiplier. LG’s linear compressor technology produces lower inrush than traditional reciprocating compressors, but we apply 2x rather than a lower figure to maintain a safety margin.
If the device’s estimated surge exceeds the power station’s published peak output (after applying our load-profile buffer, explained below), the pairing fails the surge gate.
Gate 3: Running Watts and Runtime
If the pairing passes voltage and surge, the final check is straightforward: can the power station sustain the device’s running load, and for how long?
Runtime formula
Runtime (hours) = Battery Capacity (Wh) × 0.70 ÷ Running Watts
The 0.70 factor is a derate that accounts for real-world losses: inverter conversion inefficiency, battery management system overhead, voltage sag under load, and temperature effects. Manufacturers quote the nameplate capacity of their battery cells, but what comes out of the AC outlet is always less.
Load-Profile Buffers: Why 100% Is Not Enough
A power station that technically has enough peak watts to handle a device’s startup surge is not the same as one that reliably handles it, night after night, in August heat, at 30 percent battery.
Real-world conditions degrade performance. Inverter efficiency drops as the battery depletes. High ambient temperatures force the electronics to derate. Long or undersized extension cords create voltage drop, which makes motors draw more current, not less. An older motor with worn bearings needs more juice to start than its nameplate suggests.
Our engine applies a buffer multiplier to every device’s power requirements before comparing them against the power station’s output. The buffer varies by load type:
| Load type | Examples | Buffer | Why |
|---|---|---|---|
| Resistive | Space heaters, toasters | 1.10× | Predictable, no startup spike. Covers cable losses and inverter overhead. |
| Electronic | Laptops, phone chargers, TVs | 1.15× | Switching supplies are stable, but some draw brief inrush when capacitors charge. |
| Motor | Fans, pumps, power tools | 1.15× | Single startup spike, then stable. Covers variability vs. published surge figures. |
| Medical | CPAP, oxygen concentrators | 1.15× | Same electrical profile as electronic, but failure consequences are more serious. |
| Compressor | Refrigerators, ACs, air compressors | 1.25× | Repeated surge events (40–70 restarts/day). Head pressure varies startup current. |
| Heating element | Electric blankets, ceramic heaters | 1.10× | Pure resistive behavior. |
When our engine evaluates a pairing, it multiplies the device’s power requirements by the appropriate buffer before checking them against the power station’s specs. A pairing that passes with the buffer applied earns a SAFE verdict. A pairing that passes at raw specs but fails with the buffer is TIGHT. It might work, but we will not call it reliable.
Where Our Data Comes From
Every number in our database has a source, and every source has a confidence level. We rank them in a hierarchy, from highest to lowest confidence:
From the device owner's manual or installation guide.
CRAFTSMAN CMEC6150 lists 1,320W running / 6,800W starting in official support docs.
From the manufacturer's product page, spec sheet, or FAQ.
CRAFTSMAN also publishes these figures on their support website.
Derived from NEC Table 430.248 (full-load amps) and Section 430.7(B) (locked-rotor code letters).
Motors that list only horsepower and voltage on their nameplate.
Annual energy figures from ENERGY STAR, DOE CCMS, or AHRI directory listings.
LG LMXS28596S: 760 kWh/year from ENERGY STAR, converted to running watts via duty cycle.
Surge estimated from a category multiplier derived from similar devices with known data.
Metabo HPT EC914S surge estimated at 5.15× from the comparable CRAFTSMAN CMEC6150.
Every compatibility page on GeneratorChecker displays a confidence badge showing which source level applies to each data point. If you see ENGINEERING_ESTIMATE, you know we are working from an informed projection, not a manufacturer’s published number. If you see OEM_MANUAL, you know the number comes straight from the device’s documentation.
Why does this matter? Because a SAFE verdict backed by OEM_MANUAL data is more reliable than a SAFE verdict backed by ENGINEERING_ESTIMATE. Both pass our checks, but the margin for error is different. We show you the source level so you can make that judgment for yourself. Most competitor sites give you a single “yes/no” compatibility answer with no indication of where the underlying data came from. We think you deserve to see the work.
The Five Verdicts
Every pairing in our database receives one of five verdicts. Here is what each one means, and what it does not mean.
Passes all three gates with safety buffers applied. Our highest confidence verdict.
• When it happens: The power station has comfortable headroom on both running and surge watts.
• Example: EcoFlow DELTA Pro 3 (4,000W / 8,000W peak) vs. ResMed AirSense 10 CPAP (53W / 104W peak) — roughly 75× the required surge capacity.
Passes at raw specs but fails when the safety buffer is applied. May work in ideal conditions — not recommended for emergencies.
• When it happens: Full battery, moderate temperature, short cable run. Change any of those and it may trip.
• What to watch for: This is the most common source of buyer frustration — works during a backyard test, fails during a heat wave at 25% battery through a 50-foot extension cord.
Surge exceeds peak output, but a soft-start device could fix it. We model a 0.45 reduction factor (surge cut to 45% of original).
• When it happens: Compressor-driven devices (ACs, refrigerators) paired with mid-range power stations.
• What to do: Install a soft-start device such as a MicroAir EasyStart. Our 0.45 factor is conservative vs. manufacturer claims of up to 75% reduction.
The power station cannot run this device. Continuous output or surge capacity is insufficient, even with a soft-start device.
• When it happens: Small stations paired with high-draw appliances.
• Example: EcoFlow RIVER 2 (300W / 600W peak) vs. Frigidaire window AC (670W running / ~2,010W surge) — running watts alone exceed the station’s continuous output.
The device requires 240V and the station outputs 120V only. A structural electrical mismatch — no amount of wattage compensates.
• When it happens: Central ACs, well pumps, electric water heaters, or clothes dryers paired with any 120V-only station.
• What to do: Look for a 240V-capable station — only five models in our database support it.
What We Do Not Claim
Transparency cuts both ways. Here is what GeneratorChecker is, and what it is not.
We are not a testing laboratory. We do not plug devices into power stations and measure current with an oscilloscope. Our analysis is based on published specifications from manufacturers, government databases, and the National Electrical Code. Spec-based analysis has real value (it is repeatable, scalable, and transparent), but it is not a substitute for hands-on testing, and we do not pretend otherwise.
We are not UL listed, NEMA certified, or affiliated with any standards body. Our methodology references NEC tables and standards because they represent the most widely accepted electrical engineering reference in the United States, not because we claim any formal relationship with the National Fire Protection Association. NEC editions are updated on a three-year cycle, and adoption varies by state and local jurisdiction. Our references are to the 2023 edition; your local code may differ.
We are not a substitute for a licensed electrician. If you are connecting a portable power station to your home’s electrical system through a transfer switch or subpanel, hire a professional. Our compatibility analysis covers the electrical relationship between the power station and the individual device, not the installation or wiring. Nothing on this site constitutes electrical or medical advice.
Sources: CRAFTSMAN CMEC6150 starting and running watts from CRAFTSMAN Support. Frigidaire FHWC084WB1 running watts from Frigidaire product specifications (670W at 5.9A, 115V). LG LMXS28596S consumption derived from ENERGY STAR product data (724 kWh/year). EcoFlow DELTA 2 Max specifications from EcoFlow product page (2,048 Wh, 2,400W). EcoFlow DELTA Pro 3 specifications from EcoFlow product page (4,000W / 8,000W peak). NEC 2023 Article 430, Tables 430.248 and 430.7(B). ResMed AirSense 10 power consumption from ResMed Battery Guide (53W typical, 104W peak).