Power issues with power drill physics help needed please

[uart]

Its a powered screwdriver...sorry for that confusion it was my bad. Here is a link to what it is https://www.amazon.com/dp/B0000223HR/?tag=pfamazon01-20

Ok given all the info at hand I think I can solve this one now.

The battery on that unit is not particularly big 2.4V 1.33A-hr NiCad. Even a relatively small NiCad like this can still provide quite large current, perhaps even more than 30 Amps, but 30Amps is somewhere in the right ball park.

Torque is directly related to current so one way or another (directly or indirectly) it has to be caused by too lower current. Given the low voltage operation I would therefore say that the problem is most likely due to the increased resistance caused by the added wiring and connections.

The internal resistance of a NiCad cell can easily be as low as 1/60C, so for that pack (2 cells in series) I'd expect 25 milliohms or even less. You should check the wire gauge/length you're using and it's resistance but it's quite possible that it could be more than the battery internal resistance, which would definitely have an effect on performance.

 

[russ_watters]

Another possible issue is the rated voltage of the battery might not match the real/actual voltage. Ie, though the rated voltage of a Nimh is 1.2V, the real nominal voltage is 1.38. So if your 2.4V pack really needs to be 2.76V, that, combined with a difficulty in getting the amperage you need could be the problem.

For 30A, you probably want #14 or #16 wires, if they are short to minimize resistive losses in the wiring.