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dannylsmith
Joined: 21 Feb 2006 Posts: 9 Location: Panama City Beach, FL
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Posted: Wed Jul 04, 2007 11:17 am Post subject: Battery Won't Take a Charge |
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I have a couple of 12V Panasonic batteries that came out of a computer UPS
that are much like the Odyssey PC680.
They've been setting on the bench for months and only shows about 11.4V.
(They were ok when I last used them.)
When I hook the battery charger up they measure 12.9V but the charger shows
0 amps. If I leave it hooked
up the 12.9V measurement remains but still 0 amps. If after several hours of
being hooked to the charger I
unhook it they still read 11.4 V again.
Is this a charger problem or battery problem?
Danny
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dannylsmith
Joined: 21 Feb 2006 Posts: 9 Location: Panama City Beach, FL
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Posted: Fri Jul 06, 2007 7:32 am Post subject: Re: Battery Won't Take a Charge |
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Can someone take a guess at this question?
Thanks, Danny
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mprather(at)spro.net Guest
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Posted: Fri Jul 06, 2007 8:38 am Post subject: Battery Won't Take a Charge |
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What's the question? We have a short attention span (at least I do,
anyway), so it's probably a good idea to completely re-ask questions that
don't get answered.. In the interest of being helpful, and because I was
curious, I looked in the archive. A requote:
"I have a couple of 12V Panasonic batteries that came out of a computer UPS
that are much like the Odyssey PC680.
They've been setting on the bench for months and only shows about 11.4V.
(They were ok when I last used them.)
When I hook the battery charger up they measure 12.9V but the charger shows
0 amps. If I leave it hooked
up the 12.9V measurement remains but still 0 amps. If after several hours of
being hooked to the charger I
unhook it they still read 11.4 V again.
Is this a charger problem or battery problem?
Danny"
Both batteries are at 11.4V? The charger behaves the same way when
attached to each separately?
Sounds like a charger problem though 11.4V no-load says the battery is
quite dead, or might have a damaged cell. I think 12.9V isn't enough to
really charge a battery - maybe _very_ slowly. You'll need something more
like 13.5V-14V to make anything happen.
You don't mention what kind of charger you are using..
You could take that charger and attach it to a battery that appears to be
healthy (maybe on your car) and see what it puts out. If it reaches a
normal charging voltage and current then your Panasonic(s) is(are)
probably damaged in some way.
Regards,
Matt-
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rjquillin
Joined: 13 May 2007 Posts: 123 Location: KSEE
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Posted: Fri Jul 06, 2007 8:40 am Post subject: Battery Won't Take a Charge |
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At 12:10 7/4/2007, you wrote:
Quote: |
<dsmit132(at)bellsouth.net>
I have a couple of 12V Panasonic batteries that came out of a computer UPS
that are much like the Odyssey PC680.
They've been setting on the bench for months and only shows about 11.4V.
(They were ok when I last used them.)
When I hook the battery charger up they measure 12.9V but the charger shows
0 amps. If I leave it hooked
up the 12.9V measurement remains but still 0 amps. If after several hours of
being hooked to the charger I
unhook it they still read 11.4 V again.
Is this a charger problem or battery problem?
Danny
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Battery problem.
I won't hazard a guess as to the exact failure mechanism, but as I
understand it, one or more cells or internal connections go high
resistance and the battery is unable to supply or accept any current.
Ron Q.
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nuckollsr(at)cox.net Guest
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Posted: Fri Jul 06, 2007 11:28 am Post subject: Battery Won't Take a Charge |
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At 08:32 AM 7/6/2007 -0700, you wrote:
Quote: |
<dsmit132(at)bellsouth.net>
Can someone take a guess at this question?
Thanks, Danny
--------
Danny
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I agree with Matt that the voltages you've quoted raise some
questions as to the condition of your charger. Consider a
trip to Walmart to pick up a Schumacher WM-1562 charger.
They're under $20 and very smart. An exemplar charging
profile for this device is shown at:
http://www.aeroelectric.com/Pictures/Curves/schumacher_3.jpg
Your batteries need to be charged with a constant current
until voltage rises to something between 14.5 and 15.0 volts
for a SHORT period of time. After the battery is topped off,
the charger output relaxes to something just over 13 volts
and stay there no matter how long the charger is left connected
to the battery (maintenance mode).
After you've cycled the batteries over a known good charger,
the minimum test for battery integrity would be to load
them t0 about 300 amps and see how long it takes for
the voltage to drop below 9 volts. You can do this with
an inexpensive but well crafted device from Harbor Freight
http://www.aeroelectric.com/Pictures/Tools/Battery_Testers/HF91129_4.jpg
These run about $60 normally but go on sale from
time to time for less. I think I paid $40 for the
one I have. If you done wish to acquire this capability,
then go to a automotive service station and see if
they'll test them for you. Hold 300 amps for 15
seconds . . . the voltage should be 9.0V or greater
at the end of 15 seconds.
If that test is good, then it's probable that the
batteries are fit for service in the airplane but
it would be a good thing to check for capacity either
in the airplane or by conducting some sort of endurance
bench test like that described in:
http://www.aeroelectric.com/articles/battest.pdf
or with a capacity tester like:
http://westmountainradio.com/CBA_ham.htm
The short answer to your question is, we believe your
charger may not be working properly to top of
a lead-acid battery. If push comes to shove,
you can hook one of the batteries right to
your cigar lighter in the car and leave it plugged
in for a few days of driving around. I have
several such adapter cables that travel with
me to maintain instrumentation batteries in the
field.
Bob . . .
----------------------------------------
( "Physics is like sex: sure, it may )
( give some practical results, but )
( that's not why we do it." )
( )
( Richard P. Feynman )
----------------------------------------
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nuckollsr(at)cox.net Guest
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Posted: Fri Jul 06, 2007 8:45 pm Post subject: Battery Won't Take a Charge |
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At 10:34 AM 7/6/2007 -0600, you wrote:
Quote: |
What's the question? We have a short attention span (at least I do,
anyway), so it's probably a good idea to completely re-ask questions that
don't get answered.. In the interest of being helpful, and because I was
curious, I looked in the archive. A requote:
"I have a couple of 12V Panasonic batteries that came out of a computer UPS
that are much like the Odyssey PC680.
They've been setting on the bench for months and only shows about 11.4V.
(They were ok when I last used them.)
When I hook the battery charger up they measure 12.9V but the charger shows
0 amps. If I leave it hooked
up the 12.9V measurement remains but still 0 amps. If after several hours of
being hooked to the charger I
unhook it they still read 11.4 V again.
Is this a charger problem or battery problem?
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Just for grins, hook up the charger and watch the voltage
while the charter is on. see if you can get a measurement
every 15 minutes or so as long as it's changing. What we'd
LIKE to see is a slow climb to 14.5 volts or more.
However, you mentioned that these batteries had been in
service on a UPS . . . do you know for how long? And were
they removed from ACTIVE (UPS plugged into the wall) service?
If allowed to set in a discharged state for very long,
the batteries will self-destruct.
Bob . . .
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