My HP-15C revives......

[Steve Simpkin]

(10-04-2018 04:28 PM)Thomas Okken Wrote:  I wonder about the usage pattern of people whose Voyagers run for over decade before needing new batteries. I used to own an HP-10C in college, which I used a lot; I used it in my studies and exams, and I enjoyed the challenge of programming it, with its severe limitations (I also had a 41CX, on which, of course, everything was easy). I would run through a set of batteries in a matter of months -- and I started using even more after I had had it undergo speed-up surgery (which was slightly disappointing, I think it was about 1.6 times faster afterwards, while I had expected 2x).

I'm not complaining about several months on one set of batteries; I actually thought that was pretty good, given how heavily I used it. But how do you make a set of batteries last 10, 15, 20 or even more years?

Hmm, maybe my 10C was just out of spec? I don't have it any more, but I did buy a used 10C on eBay a while ago; I guess I could just pop a fresh set of batteries in there and set it to run a program with an endless loop, and see how long it takes before the low-battery warning comes on, and how long before it dies. If anyone has run this kind of test before, what did you find?

I bought my HP-11C new in early 1987 and sold it around 2000. It still had the original alkaline batteries that it came with. The low battery indicator had just started to come on occasionally. I had used it heavily at my job for about a year until I bought a used HP-28C (followed by other HP models). After that I very rarely used my HP-11C.

From the HP-11C Owner's Handbook (P230):
"A set of alkaline batteries will provide at least 80 hours of continuous program running (the most power-consuming kind of calculator use). A set of three fresh silver-oxide batteries will provide at least 180 hours of continuous program running."

"If the calculator remains turned off, a set of fresh batteries will preserve the contents of Continuous Memory for as long as the batteries would last outside of the calculator - at least 1-1/2 years for alkaline batteries or at least 2 years for silver-oxide batteries."