How to home make a battery for HP25/c/21

From: Ron Hudson <>
Date: Tue Nov 9 13:14:33 2004

1. Obtain radio shack part numbers 23-149 1000mAh Nicad Batteries (2),
270-382A 2 cell AA battery

2. Snip off the snap end, the plastic is a little brittle, so I used
Diagonal Cutters to cut
        it off right where the flat plastic that holds the snaps

3 Snip off the spring from the snap part and place it in the bottom of
the cell holder.

4 Install the two NiCad batteries one with positive showing, one with
negative showing

5 Insert the assembly into the back of the calculator, you will have to
compress the springs
        to get it to fit. The positive battery should touch the left terminal
in the calculator as
        you are holding the calculator with the terminals up (upside-down),
viewing the back.

I use a slip of cardboard to close the back cut into a rectangle with
one tab on one side and
2 tabs that fit into the slots on the calculator. An X-Creditcard or
somthing of that same
thickness would work better.
Received on Tue Nov 09 2004 - 13:14:33 GMT

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