How we work

Math

Every runtime shows its work

This site does not run a testing lab, and it will never pretend to. What it does instead is arithmetic nobody else bothers with: every capacity number is attributed to the manufacturer's own spec page, and every runtime figure is computed from it in the open — real appliance duty cycles (a fridge compressor runs about a third of the time), an 85% inverter-efficiency haircut, and loads sourced to DOE and device-maker documentation. Spec sheets assume a perfect inverter and 100% depth of discharge; our numbers include the losses, which is why they're lower and why they're useful.

Every estimate is labeled as an estimate, and the formula travels with it — you can check any number on this site with a calculator, and you're invited to.

Source

Every claim carries a citation with a date

Every factual claim — a price, a spec, a commission-relevant detail — is backed by a source you can see in the ledger at the bottom of each page, with the date we last checked it. Citations older than 120 days fail our build: the page cannot ship until the claim is re-verified or removed. Prices and promos in this niche move fast; a dated citation is the difference between information and rumor.

Money

Affiliate links never touch the rankings

This site earns commissions from some links — every one of them is marked, routed through a visible /go/ redirect, and tagged rel="sponsored". Picks and rankings are decided on the math first; the links get attached afterward. No brand sees a draft, buys a placement, or edits a verdict. If a recommendation ever changes because the commission changed, that would be a correction-level failure — see the next section.

Correct

Substantive changes are logged in public

When a claim changes after publish — a corrected spec, a re-tested runtime, a retracted recommendation — the change is logged on the corrections page with a date and what changed. Typo fixes don't get entries; anything that could have changed your buying decision does.