Why are the HP Prime and HP-35s so unpopular?

[Garth Wilson]

(01-24-2021 12:46 PM)Maximilian Hohmann Wrote:  Hello!

(01-24-2021 09:31 AM)Garth Wilson Wrote:  I also don't want a proprietary battery that may not be available when it needs replacement years or decades down the road. I wish my 41 (which I use every day) used AAA cells like my 71 does; but at least the N cells are still available, even now after 40 years, even if not as cheap as AAA's.

I would say that the N cells of the HP-41 were then and are now much rarer than the Lithium battery of the Prime. The latter is used in many mobile phones and (probably) manufactured in much larger numbers than N cells ever were. And rechargeable N cells have always been quite rare.

True, but even though N cells have never been very common, they have been around for at least 42 years (I can't find what year they were introduced, but it had to be before the 41 was designed) and will be around for probably decades more. Mobile-phone batteries won't be able to compete with that. Mobile phone models are a here-today-gone-tomorrow proposition, and mobile phones just don't last. I suspect that in two or three more decades, any mobile-phone battery available today will have long been discontinued, whereas N cells may still be available.

Quote:I started my calculator life 1975 or 1976 first with a green VFD model followed by a red LED calculator. Both would last between 5 and 10 hours on a fully charged battery pack. Therefore it became natural to me to keep an eye on the charging state of the batteries, especially before an exam or similar event where recharging halfway through was not possible.

I started with a TI-58c and then TI-59. Supposedly a full charge was good for four hours; but I never could get more than 2½, even brand new. I would also put only a decimal point in the display to reduce the current when leaving it idle, especially for the 59 which would lose its memory if you turn it off for even a second, and a program would have to be re-loaded from cards.

Quote:Just like one refuels one's car before setting off for a long trip early in the morning or late at night.

For my first 2½ decades of HP-41cx use, a set of batteries would last a couple of years of regular, daily use. I don't want to have to be thinking about charging regularly. (And no, I don't use a cell phone.) When I got the double extended memory module, it dropped to six months, as it clearly has some current leakage. With Diego's Clonix-D module, it went down to ten weeks, but then I realized the problem might be coming from buying cheap N cells on eBay that might have been counterfeits rather than being what they were labeled. I just put the real thing in to see how they last now.