Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!hp4nl!kunivv1!ge
From: ge@kunivv1.sci.kun.nl (Ge' Weijers)
Newsgroups: comp.sys.handhelds
Subject: Re: Rechargeable batteries for the hp28s
Message-ID: <1058@kunivv1.sci.kun.nl>
Date: 19 Feb 90 16:39:52 GMT
References: <5923@skinner.nprdc.arpa> <6824@sdcc6.ucsd.edu> <7960@cbnewsh.ATT.COM> <4102@ccncsu.ColoState.EDU>
Organization: University of Nijmegen, The Netherlands.
Lines: 42

jn163051@longs.LANCE.ColoState.Edu (Joel Nevison) writes:

>I would not reccomend using NiCd batteries in the 28s for the following
>reasons:
>1) NiCd batteries won't last as long as a good alkaline battery, NiCd's
>hold less amp hours per unit volume.   NiCd's also tend to self discharge
>over long periods of time ie. several months.   This could produce some
>nasty surprises when you find your 28s NiCds drained (memory lost).
Does the HP28 run reliably on 3.6V in stead of 4.5V? I wonder...
I regularly use a Z88 portable computer I keep fed with NiCd batteries.
Normal AA Alkalines are drained after about 20 hours, so this is definitely
economically sound.
NiCds usually last about a month on standby mode. So if you store the
Z88 (or HP28) when you go on a holiday remember to put in a set of normal
alkaline batteries. AA (penlight) NiCds are cheap, chargers are common
and cheap. This is not true for AAA type chargers.

>2) NiCd's forte is the ability to produce high currents for a short time, as
>opposed to the requirement of a 28s (low currents for a long time).
They're not that bad in low-current applications. Remember to discharge them
fully (to 1V) once in a while to prevent the memory-effect from occurring.

>3) What are you going to power your 28s with while your NiCd's charge?
>Note - most chargers take eight hours.
Alkaline batteries, of course, or take 2 sets of NiCds.

>4) How often do you need to replace your batteries anyway?   Mine have been
>going for over 14 months now.
You might break even on your investment in perhaps a few years. Add up
the cost of a charger and 6 NiCds, and figure out how long it takes before
you break even. Is this worth all the hassle?

>I'd say go with HP's reccomendations on this one.
I couldn't agree more.

Ge' Weijers


Ge' Weijers                                    Internet/UUCP: ge@cs.kun.nl
Faculty of Mathematics and Computer Science,   (uunet.uu.net!cs.kun.nl!ge)
University of Nijmegen, Toernooiveld 1         
6525 ED Nijmegen, the Netherlands              tel. +3180612483 (UTC-2)