HP-15C CE often freezes

[Johnh]

It's good to see that the source of the issues is identified ,as battery power, even if the best way to deal with it is still being considered.

A program to solve Soduku sounds very clever! But if it's driving the machine at full speed for a considerable time then that could be a significant drain.

You can't directly tell a CR3032's ability to maintain voltage when supplying a given current except by testing under load. But my rule-of-thumb is to note that a new one fresh out of the blister-pack measures at least 3.3V unloaded, and I test occasionally and replace them when they measure less than 3V unloaded. At this point, they are still good for many other less critical gadgets, so I move them on.

I'm not running long routines on mine, just short quick but useful ones, and general ad-hoc number punching. On that basis, I changed after a year on my 15C-CE. I also have the VoyagerSave app going now, and I use emulators for most messing around with new program ideas.

Based on that, I'll see how long it takes to get too low for my use, and then retest the batteries unloaded and then loaded to see if I want to adjust my values.

[rprosperi]

(10-27-2024 02:48 PM)BuSchu Wrote:  

(10-27-2024 09:56 AM)Steve Simpkin Wrote:  You might want to try new batteries anyway. Coin batteries often lose their current capacity before their voltage drops very much making them hard to create an accurate low battery indication.

Thank's a lot, Steve. You are right. I tested the batteries with my multimeter: Open curcuit 2,9 V, under load 2,5 V. Seems to bee too little for the calculator. But the empty battery indicator also seems to be a waste of time. :-(

With new batteries, the calculator runs like new again. But if the batteries run out, you can lose the fun of using the calculator. It's a collector's edition.

This is very common on many new high-end calculators, and why this was the first advice offered 17 minutes after your initial post, but perhaps you missed it.

The voltage drop off cliff is soo steep in these thin cells that extended run time of such devices, sucks all the energy out getting very close to the edge of the cliff. In manual mode, as you type commands, the cell still has enough to power the small spurts requited, but as soon as you have a heavty draw, the voltage gets pulled down below threshold value and wonky things start to occur.

These are the first positive comments I've heard about using rechargeabe 2032 cells, I may give it a shot, I go through a LOT of them.

[AnnoyedOne]

(10-28-2024 12:55 AM)rprosperi Wrote:  In manual mode, as you type commands, the cell still has enough to power the small spurts requited, but as soon as you have a heavty draw, the voltage gets pulled down below threshold value and wonky things start to occur.

I'm sure that no-one considered that a HP-15C CE would run a program for a few minutes.

Every program I've run completed in less than a second. Slower on a HP-15C.

I'd use a computer or emulator/simulator for long programs.

As for LIR2032's I wish you luck!

A1

[MinkLib]

A Google search gives 45mAhr for the rechargeable LIR3032, 225maHr for the CR2032.
So the rechargeable doesn't look like much of a substitute on paper?

[AnnoyedOne]

(Yesterday 06:23 PM)MinkLib Wrote:  A Google search gives 45mAhr for the rechargeable LIR3032, 225maHr for the CR2032.

I saw 45/120/180mAh. Still less than 240mAh for Energizer ECR2032's.

I bought mine cheap (less than LIR2032's).

A1

[Commie]

Hi,

I agree with A1, it's simply not worth it going rechargable, it would take years to get payback.

Cheers
Darren