Creating NiCD pack for HP-41



#2

Hi,

as I've got several HP-41s, which I activate only from time to time, maintaining battery power is either a hassle. Either I switch calcs with only one complete pack or I have to buy quite a lot of these expensive N cells.
I wasn't yet lucky (or willing) enough to get a NiCD rechargeable pack.

Has anybody come around DIY instructions how build a NiCD pack from a normal battery holder? The only things I've seen so far were REbuild instructions, but, as it says: rebuilding is not possible without the building :-)

N sized cells are not too hard to find, it's the connection to the charger, that troubles me.

Thanks for any help.
Klaus.


#3

Easy, just buy four nicad "N" cells and an external charger. If you need to keep the machine alive while they charge buy eight.


#4

I found, that as long as you don't press any keys, especially the ON key, the HP-41 will hold its memory for at least a day or longer without batteries. This is for a unit that is used daily though not one that is in storage and is powered up on occasions to keep the circuits alive.


#5

Most HP41C machines can hold up for several days without batteries. CV's at least a week. I have CX machines that lasted over a month.

#6

I agree with David. In North America Radio Shack caries those (part no: 23-521), they are ~$9 for two NiMH N batteries (in Canadian dollars). As for the charger I use the regular Energizer (or Duracell) with battery charging module for N cells. That is just a spacer to convert N size into AA size, also sold at Radio Shack for $2 for 4 pieces (part no: 23-137).

1234

Edited: 2 June 2004, 3:35 p.m.

#7

.


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