Rated capacity, and why amp-hours are the wrong column

What the standard pins down

IEC 61960 covers secondary lithium cells and batteries for portable applications, and its contribution to a garden shelf is a definition: what rated capacity means and how it is determined.

Capacity is not a property a pack simply has. It depends on the current you draw, the temperature, the voltage you stop at, and how the pack was charged first. The standard’s work is to fix all of those so that a number is reproducible: the charging regime, the rest period, the discharge current expressed relative to the pack’s own rating, the cut-off voltage, and the ambient temperature.

It also fixes the marking and designation — how a cell or pack is named, and which characteristics must be stated — and it sets out endurance and other performance tests conducted under the same controlled conditions.

The practical consequence for a buyer is simple: a rated capacity is a figure obtained under a gentle, defined discharge. A lawnmower is not a gentle, defined discharge.

What it does not promise

It does not promise runtime. This is the whole of the problem on this shelf. A pack’s capacity is energy; a machine’s runtime is that energy divided by the power the machine draws, and a cordless mower’s draw varies with grass length, moisture, blade sharpness and how fast you walk. Manufacturers that publish a runtime publish a bench figure obtained under their own conditions, and this site prints it as one.

It does not make amp-hours comparable across platforms. Amp-hours are charge, not energy. A pack’s energy is roughly its charge times its voltage, so a 2.0 Ah pack on a 36 V system holds about as much as a 4.0 Ah pack on an 18 V one. Listings on this shelf compare the first number and ignore the second constantly.

It does not promise the nominal voltage on the label is the working voltage. Cordless platforms are commonly marketed at the peak voltage of a freshly charged pack rather than its nominal one, so the same hardware can be sold as 18 V or as 20 V depending on the brand’s convention. That is a naming convention, not a difference in the cells, and it has its own page here.

And it does not promise cycle life in your hands. Storage charge, winter temperatures and how deeply you run a pack down all decide how many seasons it survives, and none of them is the test condition.

The documents it sits next to

The transport and safety side of lithium packs is governed by other documents entirely. The machine the pack powers is under its own machinery and appliance standards, and the pack’s ingress rating under the IP code.

The platform names themselves — the ecosystem badges that decide whether a pack fits — are a market convention with no publisher, and they get their own page.

Which shelves it reaches here

Every cordless family cites it: battery mowers, robots, blowers, shears and the battery scarifiers.

Where a listing prints amp-hours only, this site prints amp-hours and the platform voltage together, because one without the other cannot be compared with anything. Where a runtime is quoted, the page names it as a manufacturer figure and states, where the listing says so, whether the machine is sold with a pack at all — a great many on this shelf are not.