Batteries and such


I have a bunch of small questions, mostly about batteries...

1) I've recently purchased an HP-19C and put in a new battery pack with NiMH 1850 mAh AA cells. Is it safe to recharge the batteries in the calculator? I've scoured the HP archives for information on this and it appears the consensus some time ago was that, yes, it was safe. I'm just looking for any updates to those opinions.

2) Same question for the HP-34C.

3) Any reason why a Woodstock would have problems with a rebuild pack using NiMH? I've tried a couple of packs/battery combinations and have gotten nothing. I know the batteries are ok because I can transfer them to another pack for a different type of machine and they work. I also know that the Woodstock calculators work.

3) Can you throw the HP "leatherette" cases into the washing machine? I have Voyager cases spraying the dreaded black powder and a Spice (fuzzy inside) case which stinks. Any experience here?


Yes, Nimh cells work fine in the 19C, spices, woodstocks, and classics. You need to keep them on the charger for up to three times as long, since they can hold up to three times the juice.

I have washed numerous HP41 and spice cases in the wshing machine with great success. Sometimes it takes two wash cycles to get the gunk out of a stubborn case. Air dry them with the mouth propped open.

Woodstock and HP19C machines are famous for bad battery pack connections to the machine terminals. The cells in the woodstock pack need to be able to move freely. If they are glued together or strapped tightly at the spring connection, one terminal may not be making contact. Try small wads of aluminum foil between the battery contacts and the machine terminals.

The ends of the woodstock cells should be connected by a welded strap with a little slack in it. Dont trust the springs alone to make good contacts between the cells.


Mr. Smith, please be careful that your old Spice cases are not still deteriorating chemically, in which case you would still be contact with the (most likely) harmful residue.


I only know about the Spice series black vinyl cases. The foam lining inside deteriorates over the years and leaves not only the objectionable powder, but a bit of an oily residue as well. Dollars to doughnuts this stuff is somewhat toxic or carcinogenic. Therefore, I don't advise washing them, as these things are organic molecules and water won't do much to them and they'll just continue to decompose, as the plasticizers evaporate over the years. I advise you do what I did- simply throw away the vinyl Spice case.

Nowadays, office supply places and stationery stores, especially during back-to-school season (just over) have these generic calculator cases for about $5 to about $10. They are made by the people who make notebooks, binders, etc. (Five-Star, I think, is one of the brands I can remember) But I myself have never bought one.


The lining that decomposes is apparently foam rubber... they make pillows and beds out of it... probably fairly safe. The residue washes out quite well. The spice series cases usually come out of the wash looking like new.

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