Our Methodology
Updated
Where do the numbers come from?
Manufacturer spec sheets and manuals first, then independent published tests where they exist. Every review lists its sources.
How do we make models comparable?
Capacity in watt-hours, output in watts, weight in kilograms, charge time in minutes from 0 to 100%. From these we derive energy density (Wh/kg) and price per Wh, using a dated reference price for each region.
What do the labels mean?
- Portable: under 15 kg.
- Home backup: 2,000 Wh or more, or 1,000 Wh or more and expandable with extra batteries.
- UPS-grade switchover: switches to battery in 30 ms or less.
- LFP battery: lithium iron phosphate chemistry, which typically lasts thousands of cycles.
How are ratings calculated?
Each review scores the criteria that matter for that product from 1 to 5 in half points; the overall rating is their average.
Do you test products yourselves?
No. Every review is research-based, built from manufacturer specs and attributed independent tests, and it says so at the top.