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HP Forum Archive 05

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Re: New article and battery search help
Message #1 Posted by Katie on 5 Jan 2001, 1:13 a.m.

I finally got to the bottom of the 82120 battery pack replacement cell story. The Sanyo 1/2N cells that TNR Technical used to have are no longer available. Furthermore, the person at TNR, Marty, who had rebuilt these packs in the past, is no longer working there.

I confirmed with several manufacturers and distributors that 1/2 N nicads are no longer made by anyone. However, I have found a suitable replacement: 1/3AAA size nicads. They have a smaller diameter but are only 1mm longer and therefore fit just fine. There capacity is only 50mah verses 75mah for the 1/2 N cells so they'll need to be recharged more often.

Most Sanyo distributors carry them as part number: 1/3AAA-50WT for a single quantity retail cost of $3.50, but I'm sure that can be had for around $2.00. One source for these (and where I bought them from) is Dan Tona in New York City - phone: (800) DANTONA.

Re: New article and battery search help
Message #2 Posted by Ion Abraham (New Mexico US) on 6 Jan 2001, 1:51 p.m.,
in response to message #1 by Katie


Sorry to hear about the demise of the TNR option for rechargeable battery packs. I guess it was too good to last. Kudos to you for all the digging into the battery question.

The only other thing I wanted to know is, do you rebuild the packs yourself with the new batteries you found, or have you found someone to do it?

Best regards,

Ion Abraham Albuquerque, New Mexico

Re: New article and battery search help
Message #3 Posted by Kevin Schoedel on 8 Jan 2001, 8:17 p.m.,
in response to message #2 by Ion Abraham (New Mexico US)

Recently I dismembered a "9V" nicad battery (actually 7.2V, but in the common 9V size), and guess what was inside? Six 1/2N cells. Granted, this battery was not brand new, but it had not been used much, and all the cells were good.

I haven't needed more cells, so I haven't looked at any new batteries yet. The battery casing should have one or more vents, so that it may be possible to peer inside without having to buy and open one. Even if no currently available batteries use 1/2N cells, if they do use discrete cells, as nicad packs generally seem to, and they are not long and thin, then four should fit comfortably in the same space as four 1/2N cells.

Re: New article and battery search help
Message #4 Posted by Katie on 10 Jan 2001, 12:44 a.m.,
in response to message #3 by Kevin Schoedel


I've only done one 41C battery pack rebuild with these 1/3AAA batteries so I don't have much in the way of experience with it. I've done a zillion of the other HP battery pack rebuilds and I can tell you that this is by far the most difficult. It's too bad that Marty isn't at TNR, $20 for rebuilding one of these was a real bargain!


I've never opened up one of those rechargeable 9V batteries, but it must be an awful tight squeeze to get 6 - 1/2 N cells in there. Externally, I can't see how they can do it. Can you tell me which make of 9V battery you opened up, I'd like to see if whatever's in there might be a better to use for 41C battery re-builds.



Re: New article and battery search help
Message #5 Posted by Kevin Schoedel on 10 Jan 2001, 9:51 a.m.,
in response to message #4 by Katie

The battery I used was labelled as a supermarket house brand, from the Weston chains (Loblaws, Zehrs, etc.) here in Canada. (I don't think they sell nicads any more, but I could be wrong -- if they do still have the same ones, I'll post an offer to forward in the classified section.) I don't recall seeing any manufacturer's marking, and unfortunately I threw away the casing at the time. I do remember that the casing was black plastic, pretty thin, and the two short edges opposite the contacts were curved around the cells, giving the battery a "U" shape. There was a single round vent between the battery contacts, through which it was possible to see the first two cells. The cells were arranged in "six-pack" form, i.e. in rows with sides touching rather than in columns with contacts touching.

It turned out that the connection between the 'rows' was long enough that I could fold/twist them into a straight line. I guess one could also tear tabs off flush with the 'extra' cells to join them that way. I also 'lazily' soldered the charging circuit to the pair of spring tabs in the caculator pack, rather than to the cell tabs.

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