50g battery warning

[HP67]

This is the first set of batteries for this 50g. I'm using Duracells instead of the junk that came in the package. The battery warning has come on but it hasn't died and after sitting off for a while it can do a bunch of work before the indicator comes on again. Does anybody have a feel for how long the batteries have to live when the indicator comes on? I don't want to waste the batteries by throwing them out before their time, but dying in the middle of editing a big program is not very attractive either. I do take backups but history shows the backup you need is usually not the one you have.

[John R. Graham]

The Lithium coin cell backup battery should prevent data loss when the calculator stops working, so it's pretty safe to tickle the dragon's tail.

- John

[HP67]

Does the watch battery save the stack too? What about a program being edited?

Thanks.

[Jim Horn]

You might consider plugging it into a computer or USB power supply via the USB port and cable. The '50 is unusual in that it can draw its power from the USB, saving its batteries.

[HP67]

Thanks, that's an idea. I need to look for a long enough cable. I should have one somewhere. Will it charge the batteries on USB or is that too much to ask?

But it would be interesting to know just how much the coin cell saves- the stack, a program being edited, etc.

[John R. Graham]

(06-06-2014 02:46 PM)HP67 Wrote:  Does the watch battery save the stack too? What about a program being edited?

No, neither. But it does safe the contents of all stored programs, variables, and current calculator settings (e.g., flags, current directory).

- John

[HP67]

Thank you. Well, that's better than nothing!

[Jim Horn]

The '50 was designed with primary (non-rechargeable) cells in mind so it won't recharge its batteries when USB power is available. And good thing, too - the differences between nickel cadmium, nickel metal hydride, various lithium and other rechargeable cells combined with the potentially disastrous effects of trying to recharge primary cells would almost certainly guarantee many damaged calculators had they included charging.

Generic but good alkaline AAA cells are inexpensive and great for travel - a small set of spares takes little room and allows immediate replacement when needed. The USB option is good when working extended sessions at the desk. It's nice to have both options!

[HP67]

Agreed. I don't like rechargeable batteries that are fixed in place although I often do use AAA or AA rechargeables. But yeah, keeping extra sets of batteries around is no problem, and Duracells are long dated nowadays and they seem tight and I have never had a leak in decades of using them. But there is still the problem of not knowing when to throw a set of batteries in the trash...

[HP67]

I kept using it until I got the warning steady whenever I turned on the calculator.

Before throwing the batteries out, I decided to try them in another device. Two of the 4 castaways are now happily powering an old Palm Pilot and the battery meter shows 40%.

So after your HP 50g says your batteries don't cut the mustard, don't throw them out without checking whether they're good enough for some other AAA-powered gadget!

[ElectroDuende]

(06-08-2014 05:50 PM)HP67 Wrote:  I kept using it until I got the warning steady whenever I turned on the calculator.

Before throwing the batteries out, I decided to try them in another device. Two of the 4 castaways are now happily powering an old Palm Pilot and the battery meter shows 40%.

So after your HP 50g says your batteries don't cut the mustard, don't throw them out without checking whether they're good enough for some other AAA-powered gadget!

The ones that come from my calculator with steady warning can power the remotes for my tv and/or Stereo for months...