Fredxx wrote:

The Natural Philosopher wrote:

Actually its 3.7V and 4.2V

3x3.7V = 11.1V nominal or 3x4.2V=12.6V fully charged
5x3.7V = 18.5V nominal or 5x4.2V=21V fully charged
10x3.7V = 37V nominal or 10x4.2V=42V fully charged

Yes, but of course none of the tool manufacturers make batteries
advertised as any of those voltages.

And you can wind a motor for any voltage you want. And build a lithium
cell to any capacity you want...

Contact resistance and electronics tend to favour a higher voltage lower
current. The limit being what is considered safe for the human body and
how many cells you can get in a package.

Dewalt have switchable 18V/54V batteries, presume without talking to a
high-voltage tool the battery defaults to 18V to avoid users touching
54V terminals, and so counts as ELV?