On 18/12/2020 12:38, Fredxx wrote:
On 18/12/2020 12:06:39, The Natural Philosopher wrote:
On 18/12/2020 11:18, Andy Burns wrote:
PeterC wrote:

Bosch 10.8V are now 12V but can be used with the 10.8V battery.

That's just the old marketing vs technical MOAAR POWAH! argument

3x3.6V = 10.8V nominal or 3x4V=12V fully charged
5x3.6V = 18V nominal or 5x4V=20V fully charged
10x3.6V = 36V nominal or 10x4V=40V fully charged

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

Of course the voltage is supremely irrelevant and goes back to the
days when all there was was a 600mAh 1.2v sub C nickel cell. If you
wanted more capacity you had to stack em in series.

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.


Not necessarily. There is a broad sweet spot between 10v and 200V. and
10A an 100A. Contact resistance doesn't come into a modern variable
speed brushless.

And calculations show that where motors are concerned the same weight of
copper in a few fat turns or a lot of thin ones ends up the same if you
adjust the voltage..

To be sure if you are cheapskating the power FETS a higher voltage lower
current is a bit less demanding in terms of 'on resistance'

And wires in excess of 100A get pretty unweildy.


--
Canada is all right really, though not for the whole weekend.

"Saki"