From: duenodemonte on 17 Oct 2006 11:30
Another year with my HP49G+ (three) and I will never know when I should
change the CR2032 backup battery.
Thanks to www.adictoshp.org I have a graphical show of the AAA battery
charge, but, what about the backup one. Is there any way / experience
to know when should I change it ?
Thanks for comments.
From: Zeno on 17 Oct 2006 12:30
In article <1161099041.389596.202620(a)i42g2000cwa.googlegroups.com>,
> Another year with my HP49G+ (three) and I will never know when I should
> change the CR2032 backup battery.
> Thanks to www.adictoshp.org I have a graphical show of the AAA battery
> charge, but, what about the backup one. Is there any way / experience
> to know when should I change it ?
> Thanks for comments.
You should not have to change the Lithium backup battery for many yers
with normal use. (Normal use being regular working AAA batteries also
in place) Lithium batteries have a very long "shelf" and "use" life.
From: John H Meyers on 17 Oct 2006 13:17
The original HP48[S/G]X series had the ability
to detect not only low-voltage main batteries,
but also low-voltage plug-in card batteries,
and to display an appropriate message for each.
Various PDAs (such as my Sharp Wizard)
also make it known when either its main
or its backup battery needs replacement,
and they tell me which one needs replacing.
So it might be a logical question to inquire
whether there would ever be a warning message
about replacing the ARM-based calc series backup battery,
or else should one replace it every year, or how often?
How long might the backup battery last when good main batteries
are always in place, vs. how long when main batteries are dead?
(Sharp actually specifies all these things in its Wizard manual,
so they are aware that these things are significant to owners).
I have not seen any definitive answers for HP calcs, but
I did an experiment last year which suggested that these calcs
might have *no* low-battery detection for the backup cell
(in particular, removing the cell failed to trigger any message)
It's too bad the ARM-based calcs don't use the same coin cell
as the 48-series RAM cards, for then the answer might be
to transfer the cell to a 48-series RAM card, plug the RAM card
into a 48-series calc and turn it on, and the good old HP48
would then tell you whether the cell needed replacement :)
From: bokubob on 17 Oct 2006 16:35
>From Page 26-9 of the HP 49 User's guide* (edition 4, p/n F2228-90006):
A CR2032 back up battery is included in the calculator to provide power
backup to volatile memory when changing the main batteries. It is
recommended that you replace this battery every 5 years. A screen
will indicate when this battery needs replacement.
* Available for download at:
From: bokubob on 17 Oct 2006 16:36
>From Page 26-9 of the HP 49 User's guide*
Sorry, I meant 49g+