Topcats, HP82143A and HP82161/82162 Battery Pack


Hi, all;

I am trying to 'make one out of two' HP82143A and both units have no battery terminals. I also have an HP97 with a broken battery terminal and another complete, working HP82143A. And one working battery pack... Nothing is perfect, though.

Having three units and a lack of battery terminals led me to search for a possible updated, readily available replacement. I found what seems to be a solution and, although it is not yet implemented, I´m adding pictures for your evaluation. (you may click on each image to enlarge it)

Now I´m reasoning about a way to connect the batteries with each other and fix them in place. I will use a two-pole connector like the ones used in wireless telephone batteries (maybe a pair of them to make sure enough current will be allowed to the circuit) instead of trying to rebuild original terminals.

I would like to hear from those interested on trying something like this that will not only allow the preservation of the original terminals but also will allow the safe use of the equipment with readily available components.

As soon as I have more news I´ll post.


Luiz (Brazil)

Edited: 16 Oct 2009, 2:38 a.m.


Hi Luiz,

Some electronics shops sell those recharcheable AA cells with tabs on the terminals. Perhaps that would help to connect them to each other?



Hi, Bart;

thanks for your suggestion. Unfortunately I did not find these ones around here... But surely would be faster to build the pack 8^)


Luiz (Brazil)


I would get tabbed ones, solder the tabs together & the connector's wires, then use heat shrink around the lot to make a pack.



NiCad Lady (at the URL below) will rebuild the 82143A battery pack for $18. I've seen this company at an electronics swap meeet years ago and they seemed to do good work. I have no personal experience with them though.


Is there a difference between NiCD and NiHM in an old HP rechargeable?

I'd like to try to do the same. Can someone in the US recommend a good source of the proper AA (NiCD or NiHM) with tabs? I found many Google hits, but I thought I'd ask.



If you want to keep using the same charger, it would probably be best to stay with NiCads.

Also, with all this talk of AA's, I would mention that I think my 82161A tape drive takes the same sub-C batteries, not C or AA. Sub-C rechargeable batteries made for battery pack assemblies should not be difficult to find.

Edited: 16 Oct 2009, 1:35 p.m.


Luiz, Hello!

Yes the rotted or fatigued battery terminals are a flaw in long term design.

I too am preparing a new system for the classics and the Topcats:

1  The classics are easy, purchase a standard 3 NiNH AA battery
pack with the standard female phone plug.
2 Purchase the male plug
3 Open up the classic or topcat and remove the two prongs or
whatever remains!
4 Mill a rectangular hole in the side of the battery housing in
5 Epoxy the male plug in place inside the milled receptacle.
6 attach the power wires to the male plug.
7 Insert the new battery pack (charged!).
8 Plug it in and voila, a new system for keeping the calculator
running with available battery packs.

With the topcat the battery packs are not available. If you have
an existing battery pack, diassemble it with a knife (carefully) as we want to keep the pack. Purchase the batteries and connect them, place them in the battery pack case and glue the halves together.

Now follow the above steps to modify the battery housing to accept the male battery plug. Secure the female plug and attach it to the correct poles in the battery pack and you are set to go.

This is acutally an appendix in my book for Calculators without the battery prongs due to corrosion or fatigue.

Like you, I have not yet documented the procedure but have all the bits here to complete the task.

Good luck, Geoff


1  Male and female phone connector plugs (electronics shop).
2 4 (classic) NiMH AA batteries or 4 (topcat) C batteries.
3 Knife to open up the old battery packs (optional).
4 Tape or heat gun glue to secure the batteries to each other
if not using the old battery packs.
5 tools to mill the receptacle for the male battery plug into
the calculator battery hatch.
6 Of course; wire, solder, flux and solder iron!

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