In short: we verify specs from official sources, calculate runtimes with the formula shown on the page, and say clearly what we haven’t tested. We don’t lab-test power stations (yet). Here is exactly where every number on Tested Watts comes from.
What we verify
- Official specs. Capacity, outputs, ports and charging figures come from the manufacturer’s official product page, user manual or datasheet, checked when we write or update an article. Every article links them in its “Sources” section.
- Named independent sources. If the official page doesn’t list a figure, we cite an independent source by name, or we leave the figure out and ask you to check the current listing.
- Public safety and outage data. Health and safety guidance comes from agencies such as the CDC, FDA and FoodSafety.gov, and outage data from the U.S. Energy Information Administration (EIA).
What we calculate
Runtimes and sizes on this site are estimates. We always show the formula, so you can check it or plug in your own numbers:
Hours = (battery Wh × 0.85) ÷ (device watts + 10 W)
The 0.85 accounts for conversion losses: you rarely get a battery’s full rated capacity from its AC outlets. The extra 10 W covers the inverter’s own draw with small AC loads. Example: a 1,024 Wh power station gives about 870 usable Wh (1,024 × 0.85). An average full-size refrigerator draws about 62.5 W on average, so 870 ÷ (62.5 + 10) ≈ 12 hours.
| Assumption | Value we use |
|---|---|
| Usable capacity | 85% of rated Wh |
| Inverter overhead (small AC loads) | +10 W |
| Average full-size refrigerator | 1.5 kWh/day (about 62.5 W average) |
| Efficient / older refrigerator | 1.0 / 2.0 kWh/day |
| CPAP, no humidifier | About 30 W (about 320 Wh per 8-hour night, inverter included) |
| CPAP with humidifier | About 55 W (about 520 Wh per night) |
| CPAP with humidifier and heated tube | About 90 W (about 800 Wh per night) |
| Solar panels in real use | About 75% of their rated watts |
| Peak sun hours in the U.S. | 3–6 per day, depending on location and season |
Real results vary with temperature, battery age, device settings and how often a compressor cycles. Try your own numbers in our power station calculator.
What we measure
We plan to measure the real power draw of everyday appliances, such as a refrigerator, a Wi-Fi router, a TV and a fan, with a plug-in watt meter. The measurements are taken in Colombia, which uses the same 110–120 V, 60 Hz supply as the United States. When an article includes our own readings, it will label them “Measured at home” and show a photo of the meter. Until an article says that, its numbers are calculated from specs.
What we don’t do (yet)
- We haven’t tested power stations hands-on. Our reviews are specification-based: official specs, manuals and our runtime math. Each review says so near the top.
- No scores or star ratings. Our verdicts compare specifications, not lab results.
- No prices in articles. Prices change every day, so we ask you to compare the current price at the retailer.
- No manufacturer photos without permission. Our images are illustrations or our own charts.
If we start hands-on testing, we’ll publish the test protocol on this page and label tested results clearly in each article.
Who writes and reviews
Tested Watts is written by Alejandro Rodríguez, MD, a physician (MD, Colombia) who works in rural primary and emergency care. He is not licensed to practice medicine in the United States. Articles that touch on health, such as CPAP use, carbon monoxide, heat, cold or food safety, are reviewed and approved by him, cite official sources and include this note: “This article is general information, not medical advice.”
Our independence
We may earn a commission if you buy through our links, at no extra cost to you. Commissions never decide our verdicts. If a brand ever sends us a product, we’ll say so in the article. See our Affiliate Disclosure.
Updates and corrections
Models, firmware and specs change. We show the last-updated date on every article and change it only when we make a real update. Spotted an error? Tell us, and we’ll fix confirmed mistakes as described in our Corrections Policy. The full rules we write by are in our Editorial Policy.