Message #2 Posted by Steve (Australia) on 19 Feb 2001, 5:19 p.m.,
in response to message #1 by JMB
There was an article in one of the PPC Journals that discussed the battery life of the HP41 when using a card reader. The author thought that Lithium cells should give better performance.
This person found that 2 3V lithium batteries (around AA size?) could be squeezed into the battery compartment of the HP41.
The result was far longer battery life (measured in numbers of cards that could be read).
On the basis that it's been done before, and that I never saw any subsequent warnings, I would feel that there would be no problem in using a 6V Lithium battery.
As a precaution, I would measure the battery voltage, to ensure it did not exceed 6.8v (which is about the highest voltage you'd expect from 4 fresh alkaline cells).
The fact that Lithium cells can deliver a high current is not a problem, since NiCad cells can deliver even more :-)
The major issues are the form factor, the capacity, and the cost.