Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!psuvax1!hsdndev!cmcl2!phri!rna!dan
From: dan@rna.UUCP (Dan Ts'o)
Newsgroups: comp.sys.laptops
Subject: Re: Batteries
Message-ID: <1095@rna.UUCP>
Date: 3 Apr 91 22:25:37 GMT
References: <46Gdxpf1@cs.psu.edu> <mn2G*3sf1@cs.psu.edu>
Reply-To: dan@rna.UUCP (Root Beer)
Distribution: usa
Organization: Rockefeller University Neurobiology
Lines: 16

In article <mn2G*3sf1@cs.psu.edu> cho@sol4.cs.psu.edu (Sehyeong Cho) writes:
>Now I have two (apparently) contradicting theories. The only way to be
>consistent is perhaps "before you begin recharging the battery, make sure
>it doesn't have too much charge remained."
>But then how much is too much?
>Any idea?

	I would say to go down to 1 volt per cell. The standard NiCad cell
provides 1.25volt per cell when charged. If you go too low, some cells will
reverse (very bad). Cells that are dead tend to short themselves, forming
little crystals that span the electrodes. You can save such a shorted cell
by blowing the crystal with high current (either another NiCad or a big
capacitor). But such cells are permanently crippled and tend to lose their
charge faster and have less capacity then when new.

					Dan