HP Forum Archive 19

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HP gee-whiz question (batteries) Message #1 Posted by megarat on 29 Jan 2010, 2:29 a.m. Hey all, I'm looking to solve a piece of trivia that goes beyond my own scope with HP calcs: which HP calculator was the first to use off-the-shelf batteries that still exist, abundantly, today? I mean batteries that I can buy at the corner pharmacy, not via special order from Rat Shack. Is it really the Voyagers, or am I missing something earlier? Would it be the 41C series? I'm less interested in outliers like the HP-01 or the computer-esque models (e.g., 71B). And I almost want to disqualify anything that uses N-cells because, as I understand it, the "standard size" of the cells has changed and they're now less convenient to replace with some models, e.g., the 28S/28C. Edited: 29 Jan 2010, 2:33 a.m.

Re: HP gee-whiz question (batteries) Message #2 Posted by Mohammed Hadi on 29 Jan 2010, 3:40 a.m., in response to message #1 by megarat The 41C series uses type N cells which probably match the CR-2032 coin cells (modern hp calcs, some car remote keys and PC motherboards) in terms of local store availability. Just make sure you get the 1.5V rating as they come at severl voltage levels.

Re: HP gee-whiz question (batteries) Message #3 Posted by Martin Pinckney on 29 Jan 2010, 9:34 a.m., in response to message #2 by Mohammed Hadi I think N cells are 1.5v period, unless rechargeable substitutes, in which case they would be either 1.2v or 1.25v, depending on how the manufacturer rates them.

Re: HP gee-whiz question (batteries) Message #4 Posted by Mike Reed on 30 Jan 2010, 1:17 p.m., in response to message #2 by Mohammed Hadi I don't have any at hand to measure, but as I remember it, the 'N' cells I put in my several HP-41's (when I had them) were cylindrical, about the diameter of a AAA battery, but about 1/2 it's length. They were not disc shaped at all - not even remotely like a CR-2032. These N cells were and still are widely available in the USA. I just saw a blister pack of 4 at my local pharmacy (chemist shop, for Euro friends) for less than $5.

Re: HP gee-whiz question (batteries) Message #5 Posted by Martin Pinckney on 30 Jan 2010, 10:46 p.m., in response to message #4 by Mike Reed Mike, Mohammed said they matched "in terms of local store availability", not any physical features.

Re: HP gee-whiz question (batteries) Message #6 Posted by Mohammed Hadi on 31 Jan 2010, 6:08 a.m., in response to message #5 by Martin Pinckney Thank you Martin for responding on my behalf. And thank you also for correcting my information regarding the N cell rating.

Re: HP gee-whiz question (batteries) Message #7 Posted by Martin Pinckney on 31 Jan 2010, 2:49 p.m., in response to message #6 by Mohammed Hadi There is a 12v battery that is very close to the N cell in physical dimensions. A23 I think.

Re: HP gee-whiz question (batteries) Message #8 Posted by megarat on 4 Feb 2010, 6:19 p.m., in response to message #4 by Mike Reed Quote: I don't have any at hand to measure, but as I remember it, the 'N' cells I put in my several HP-41's (when I had them) were cylindrical, about the diameter of a AAA battery, but about 1/2 it's length. They were not disc shaped at all - not even remotely like a CR-2032. These N cells were and still are widely available in the USA. I just saw a blister pack of 4 at my local pharmacy (chemist shop, for Euro friends) for less than $5. As I understand it (I'm certainly no authority on the subject): the "standard physical dimension" of N-cells went through a change sometime in the 90s, to be very slightly thicker. Someone told me this by way of explanation for why it was so difficult to remove the batteries from my (then-) HP 28c. Validation pending. Perhaps this is complete bollocks and that N-cells have always been a bugger to change on the HP 28-series (or that my own unit was an outlier), but it's the only data I have. Can anyone confirm/verify/refute? Edited: 4 Feb 2010, 6:20 p.m.

Re: HP gee-whiz question (batteries) Message #9 Posted by Bart (UK) on 29 Jan 2010, 4:17 a.m., in response to message #1 by megarat Quote: And I almost want to disqualify anything that uses N-cells because, as I understand it, the "standard size" of the cells has changed and they're now less convenient to replace with some models, e.g., the 28S/28C. It depends on where in the world you are. From my point of view, N-cells are off-the-shelf and abundant, as here in the UK I can get them at my local Tesco, in the Tesco brand even. I prefer Duracell and recently ordered some here. By the way, the 12V remote batteries are slightly smaller than the N cell, but the best advice is "always read the label".

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