How we get our numbers
Prices
We read the price published on the manufacturer's own product page, automatically, once a day. We store every reading. The "90-day low" and "typical price" figures on our pages are computed from that stored history — not estimated, not supplied by anyone. Where a price is a limited-time promotion, our history shows it as one.
Specifications
Taken from the manufacturer's published data for that model. Where two sources on a manufacturer's own site disagree, we say so on the page rather than silently picking one.
Runtime figures
Any runtime number is one of two things, and we always label which:
- the manufacturer's stated figure, or
- a calculation from rated capacity and a stated load, with the assumed inverter efficiency shown.
These are estimates. Real-world runtime is affected by temperature, battery age, load type and inverter draw, and will usually be lower.
What we never do
- We do not accept payment for a recommendation, a ranking or a placement.
- We do not publish manufacturer-supplied copy as our own.
- We do not invent test results.
Corrections
If a number here is wrong, tell us and we'll fix it and note the change on the page. Every page carries a "last updated" date and a change log.