HP-41 rechargeable battery pack repair

[burkhard]

(07-16-2018 09:03 AM)damaltor Wrote:  Also, have a look here for two-pin packs
http://www.keesvandersanden.nl/calculators/hp82120A.php
and here (my personal page) for three-pin-packs
http://malte.deringenieur.net/wiederbele...ks-82120a/

A few questions:
1. So, why does your pack have 3 pins? Is that a "Euro thing" or a "late production thing"? The packs I have myself and seen in the US (admittedly not a whole lot) are all 2-pin.

2. The base battery pack you sourced from akkuplus was NiCad rather than NiMH. Wouldn't the pack capacity have been a lot higher with NiMH, offsetting the smaller size of the 1/3 AAA? You mentioned a couple of upsides for NiCad, but it seems that NiMH is a better battery chemistry choice today. Am I overlooking something, or does your opinion still favor NiCad?

3. In addition to your site, the Dutch page above has a bunch of other nice links at the bottom. Lots of people of done these pack updates via a few different techniques. It doesn't seem too tough and I am pretty handy with such stuff, but I've got a *ton* of projects already, up to my chin, and I'm at the point I'd rather just buy one from some expert. Is there a "favorite vendor" people have who does a nice job and just sells them?

Thanks!

burkhard