Article View: sci.electronics
Article #18002Re: NICADs
From: Jim Rees
Date: Tue, 01 Sep 1987 12:39
Date: Tue, 01 Sep 1987 12:39
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Won't a great deal of heat result in a 1C charge for 16 hours? Won't this
heat result in a possible exploding battery or at the very least a damaged
battery especially if the battery is not vented?
Sorry, slip of the keys/mind.
.1C (one-tenth C) is the max safe charge rate without overcharge detection.
The standard charge is .1C for 16 hours, which allows for a full charge
even at a very low efficiency.
I've seen quick chargers go as high as 10C, but you'd better have some
pretty sophisticated full-charge detection circuitry at this rate.
If you have a battery pack that has four cells and one of them has accidently
been reversed charged, or internally shorted as you say, when these cells are
fully charged what will the shorted cell read on a volt meter?
If you burn off the short first, it will be 1.2 - 1.25, just like a normal
cell. If you don't burn off the short, it won't take a charge at all,
and even after 16 hours of .1C it will still read < .1v.
Now, can someone post similar guidelines for gel-cells? I have one that
self-discharges in about two weeks, and won't take a charging current
over 100 ma (it's a 5 ah battery) without exceeding 2.25 volts/cell.
Is it NFG?
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!uunet!husc6!mit-eddie!apollo!rees From: rees@apollo.uucp (Jim Rees) Newsgroups: sci.electronics Subject: Re: NICADs Message-ID: <37043f5d.b8ab@apollo.uucp> Date: Tue, 1-Sep-87 08:39:00 EDT Article-I.D.: apollo.37043f5d.b8ab Posted: Tue Sep 1 08:39:00 1987 Date-Received: Sat, 5-Sep-87 02:26:52 EDT References: <646@gec-mi-at.co.uk> <36f19f36.b8ab@apollo.uucp> <1762@sol.ARPA> Organization: Apollo Computer, Chelmsford, Mass. Lines: 26