Newsgroups: comp.sys.handhelds
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!laird
From: laird@think.com (Laird Popkin)
Subject: Re: rechargeables in palmtops?
Message-ID: <1991Apr29.185743.28808@Think.COM>
Sender: news@Think.COM
Organization: Thinking Machines Corporation, Cambridge MA, USA
References: <1991Apr27.161015.19757@cmcl2.nyu.edu> <1991Apr28.012501.28554@zoo.toronto.edu>
Date: Mon, 29 Apr 91 18:57:43 GMT

In article <1991Apr28.012501.28554@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>In article <1991Apr27.161015.19757@cmcl2.nyu.edu> dimitrov@lab.ultra.nyu.edu (Isaac Dimitrovsky) writes:
>>My portfolio says alkaline batteries are recommended.
>>Does anyone know if using Nicad rechargeables will actually
>>cause problems, or if it just results in shorter times
>>between battery replacement.
>
>You will have to recharge the nicads much more often than you will have to
>replace the alkalines, unless you are using your machine *a lot*.  Nicads
>discharge themselves; they won't stay charged for more than a couple of
>weeks, typically.  They really make sense only for high-power devices
>that would otherwise eat batteries like crazy.  Most handhelds nowadays 
>are sufficiently light on power that Nicads aren't worth it.
>
>I don't immediately see any problem they would cause, however.  They do
>have somewhat lower output voltage than *fresh* ordinary batteries, but
>battery-powered hardware has to be able to run on nearly-dead batteries,
>and that means being able to cope with lower voltages.

One significant difference between NiCad batteries and ordinary batteries
is the power curve as they go dead.  Ordinary batteries deliver a gradually
decreasing power level, whereas NiCad batteris deliver fairly level power
and then go dead suddenly.  What this means is that once you are warned
that power is low, you have very little time remaining on the NiCad battery
as compared to the regular battery.  Given that a Portfolio will run on
normal batteries for 2 months or so, I'd second Henry's advice not to
bother with NiCads.

- Laird Popkin