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From: email@example.com (Robert Richter)
Subject: Re: Difference between AC adapter and charger?
Date: 23 Oct 2002 05:02:43 -0700
References: <0001HW.B9D43FDF0325BBB11662EAD0@news.covad.net> <0001HW.B9D4EE870344BA681662EAD0@news.covad.net> <3DB01FBB.EAF744F9@usa.net> <0001HW.B9D572FB034E39101662EAD0@news.covad.net> <3DB02E27.firstname.lastname@example.org> <3DB2A987.FA0DD93E@usa.net> <3DB2D4FC.B566FCAE@usa.net> <37ot9.260$FS5.email@example.com>
NNTP-Posting-Date: 23 Oct 2002 12:02:43 GMT
"Peter Gottlieb" wrote in message news:<37ot9.260$FS5.firstname.lastname@example.org>...
> "Robert Richter" wrote in message
> > I took 15V (which is "way too high" for a car battery) to a charged
> > lead acid battery and the current was only 3A. Over-voltage on a lead
> > acid battery simply results in very little current that slowly breaks
> > the water apart and vents the gases (or re-combines them in the
> > maintenance free batteries). Even on a dead battery, it is common to
> > let the internal resistance of the battery be the ONLY source of
> > current limiting, and the alternator can usually handle this because
> > lead acid batteries simply won't charge very rapidly. I have seen
> > lead acid batteries that state "No current limiting needed at 13.8V".
> Leave 15V on a 12V lead battery overnight and bad things can happen. I saw
> this a couple of times with 12V 7 AH sealed batteries which got very hot and
> vented H2SO4 vapor, in one case requiring an evacuation of our offices.
I removesd the vent caps before doing this test (which I did simply
for the purpose of this thread) and it does bubble a bit hard; I would
not recommend such a high overvoltage, especially on a sealed battery;
they don't always have proper venting but rely on re-combining.
> > Very few people make it through life without hearing of a catastrophic
> > failure of a least one friend's car battery.
> Where do you live? I'd like to stay away from that area. Our batteries are
> much more civilized around here.
Not everyone I know is in the upper class and drives a car with less
than 100,000 miles on it.
Galileo being forced to admit the earth was the center of the
universe--after confession, "It still moves, though". As far as NiCd
chargers, maybe they are connected directly to a wall-wart; but after
confessing this fact, "they still aren't charged with a DC voltage"
After this post the thread will die as far as I am concerned.
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