Guides

Why the guides exist

Every ranking on this site rests on a handful of ideas: what a lumen is, why the biggest number does not last, what the cell format decides, and what a water rating promises. A ranking whose reasoning you cannot check is an opinion with a table attached, so these pages are the reasoning, written out.

They are also wired to the rankings in both directions, which nothing else in this category does. Every roundup links down to the guides that justify its ordering, and every commercial guide links up to the roundups that apply it. If you disagree with a ranking, the page explaining why it is ordered that way is one click away.

Where to start

If you are buying a light and want the shortest path: read how many lumens you actually need, then the 10,000-lumen problem, then whether you can replace the battery. Those three cover the mistakes that account for most disappointment in this category.

If you already own a light and something is wrong with it, go straight to the ownership guides: why it will not charge, why it gets hot, and how long the battery should have lasted. Those pages carry no product picks at all, because somebody whose light will not charge is not shopping.

How the guides divide

Into three groups. Literacy: lumens, candela, watts, the ANSI FL 1 standard, IP ratings and cell formats — the vocabulary that makes a spec sheet legible. Decision: whether rechargeable is worth it, whether cheap lights are any good, and which brands publish real numbers. Ownership: charging, runtime over years, and what to do when something stops working.

The idea that connects all of them

A number is only useful if you know what was measured and for how long. The ANSI FL 1 standard defines runtime as lasting until output falls to ten percent of the reading taken thirty seconds after switch-on — which means a light can post a long runtime while spending most of it far below its headline figure. Once you know that, half the marketing in this category becomes legible.

The same idea explains why a missing figure is information. Water testing is cheap and straightforward; a brand that has done it publishes the result. Runtime testing produces the output figure anyway; a brand that publishes output without duration chose not to state the second half. Neither silence is proof of anything, and both are worth noticing.

What these pages will never do

Claim we tested anything. We have no lab, no integrating sphere and no drawer of samples, and every figure on this site is the manufacturer's own, cited. What we do is compile those figures, check them against each other, do the arithmetic, and say plainly when a number is missing. That is a smaller claim than most publishers in this category make, and it is one you can verify.