Every guide on Watt & Hour is grounded in three pillars: manufacturer electrical spec sheets, verifiable arithmetic formulas, and large-scale owner telemetry. We do not pretend a single sponsored sample in a garage represents long-term reliability.
Independent research methodology for US and Canadian power systems.
How every guide and sizing recommendation goes from raw electrical engineering specs to plain, verified advice.
We extract nameplate Wh capacity, continuous wattage, peak surge capacity, cell chemistry (LiFePO4 vs NMC), ports, and charging input thresholds directly from official engineering manuals.
We apply standard AC inverter and DC-DC conversion efficiency penalties (15% to 20% loss). We compute true runtime against real 120V household loads—and publish the exact equation.
We mine verified owner reviews, forum discussions, and teardowns for patterns in BMS bugs, thermal throttling, inverter fan whine, and real-world degradation. One review is an anecdote; twenty is a signal.
We translate raw numbers into practical buying advice: which appliances a station runs, exact safety margins, who the unit suits, and where the manufacturer specs fall short.
When battery brands say a power station has 2,048 Wh, that describes the DC cell capacity. When powering a 120 V household appliance, the internal inverter must convert DC to AC power, dissipating 15% to 20% as heat.
Our standard formula applies a realistic 85% inverter efficiency: 2,048 Wh × 0.85 ÷ 300 W = 5.8 hours. No inflated runtimes. No hidden variables.
Manufacturer specs represent optimal factory testing. Battery chemistry and ambient temperatures (freezing winter camping or hot summer garages) can decrease usable capacity by 10% to 25%.
Compressor-driven appliances (refrigerators, freezers, portable ACs) don't draw steady power. They cycle on and off. Our math uses conservative duty-cycle estimates, but user usage patterns vary.
Owner reviews are crowdsourced signals, not lab tests. We screen for batch defects and recurring firmware issues, filtering out one-off shipping damage or user error.
If a manufacturer updates firmware, lowers pricing, or releases an updated revision, we update our calculations. If we ever make an error, we correct it openly and immediately.
Use our interactive runtime calculator to check how long a portable power station will run your essential devices.