|Re: HP 97 Battery Question|
Message #4 Posted by Vieira, Luiz C. (Brazil) on 11 May 2003, 12:18 a.m.,
in response to message #3 by Jon
I opened (WITH MUCH CARE NOT TO SHORTEN THEIR TERMINALS) at least ten battery packs from TELE T.A.C. series, being both SNN4258D and SNN4019E the ones I used most. I prefer the SNN4258D because it has NiMH cells (usually isolated with green plastic). There are other types I remember being disassembled, but I do not have their codes.
One thing that called my attention is that there are different batteries inside packs with same ID #. In fact, what matters is that they must keep the same Ah relation (Ampère/hour), and the cells inside are found in some different shape. I'd like to find N-size NiMH (HP41) but I think I'll never find them...
What I noticed is that in most cases, dammaged packs have one (worst case was two) bad cell, and unfortunately they are usually in the middle (Murphy's law); at least in one case the dammaged cell was in the edge so the other four ones were kept with their original metal contacts (no need to further soldering except for the terminals).
In general the cells are sub-C equivalent with a lower diameter, so you'll need something to keep them in place inside the HP97 battery holder (and all topcats plus HP82143A, HP82161/82162 and a few others use the same package). The existence of the holder eases the job, you do not need to keep batteries firmly inside the equipment, just inside the holder (the small cage). I used a small piece of thick rubber in the middle of the cage so both batteries and contacts were kept in place. As I have only one 82143A (at least so far) that uses this pack, I rebuilt only one for testing, but I have the cage for a spare that I'll rebuilt and keep for emergency.
I hope it helps a bit. Anyway, I was informed a bit ago that my provider found another host for its customer pages and the one I had to place images is already available. I'll check for this and, if applicable, I'll scan the battery pack and place images there. Keep tunned!
Luiz C. Vieira - Brazil