How We Test and Research

We use the same research process for every guide so readers can see how a recommendation was reached. Unless an article states that we tested a product ourselves, our guides are research-based and we do not claim hands-on testing.

What we look at

Real capacity and output. Rated watt-hours, continuous watts, surge watts and the number and type of ports, compared against what the product is meant to run.
Charging. AC, solar and car charging inputs, and published charge times.
Battery chemistry and life. LiFePO4 versus other lithium chemistries and the manufacturer’s stated cycle life.
Noise and size. Fan noise reports, weight and dimensions.
Warranty and support. Length of warranty and how the maker handles claims.
Safety. Certifications, recall history and instructions for safe use.
Value. What the product offers for its price tier. We do not show prices because they change often; check Amazon for current details.

Sources

We draw on manufacturer specification sheets and manuals, published reviews, buyer feedback, and official sources such as the CPSC and the EIA. We link to sources where it helps.

Runtime estimates

Runtime depends on the device load, conversion losses and conditions. Our estimates use simple Wh divided by watts maths with a realistic efficiency allowance and are guides only. Try our runtime calculator.

Safety and medical devices

We do not give medical advice. If you rely on medical equipment such as a CPAP, follow the equipment maker’s guidance and consult your healthcare provider before choosing backup power.

Corrections

If you spot an error, tell us and we will review it. We update guides as new models, recalls and information appear.