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From: wolfgang@wsrcc.com (Wolfgang S. Rupprecht)
Newsgroups: sci.electronics
Subject: Re: battery back-up
Message-ID: <1991May21.005122.15395@wsrcc.com>
Date: 21 May 91 00:51:22 GMT
References: <1991May14.154859.21874@arcturus.uucp>
Distribution: usa
Organization: Wolfgang S Rupprecht Computer Consulting, Washington DC.
Lines: 20

graham@arcturus.uucp (Graham;Thomas D.) writes:
> Got a question re using lead-acid, car battery, as power supply for
> house alarm system.  I'm using a Delco 40 month rated about 20 hrs
> (?).  [..] In a little over an hour the voltage had fell to 9 volts.
> YET, the green ball was still indicating full charge.e

It sure sounds like one or two of the cells are dry or just dead.
Probably the cell that has the little green ball is perfectly fine.

Try to find the vent caps and open them.  Many sealed cells still have
a way to get inside with a bit of prying.  Check under the "Never
Needs Service" label for the service plugs. ;-) I bet you will find
that you boiled much of the electrolyte off of a cell or two and this
is your problem.  Fill these problem cells with water and and charge
for a goodly amount of time.

-wolfgang
-- 
Wolfgang Rupprecht    wolfgang@wsrcc.com (or) uunet!wsrcc!wolfgang
Snail Mail Address:   Box 6524, Alexandria, VA 22306-0524