dennis@home wrote:

A fully charged 18V LiIon ryobi battery is about 20V not 18V.

I expect they have just decided to use the same number of cells and
quote the fully charged voltage.

20V vs 18V is the USA vs UK marketing trick, but "rounding up" from 18V
to 40V would be quite a trick, doubling the number of cells, and *then*
counting 4.0V/cell rather than 3.7V quite possibly, Milwaukee already
produce 60V packs.