Posted by ads on January 5, 2019, 4:05 am
On Fri, 4 Jan 2019 12:41:49 -0500, "Jim Wilkins"
><ads> wrote in message
>> On Thu, 3 Jan 2019 09:14:42 -0500, "Jim Wilkins"
>>
>>>Have you needed to replace AGMs yet? My experience with 12V18Ah AGMs
>>>is that they deteriorate after around 5 years and can't be restored,
>>>while flooded batteries are useable for at least 10 years if kept
>>>charged.
>>>
>>>-jsw
>>>
>>
>> The AGMs were purchased used, a data center UPS changeout at 5 years
>> (rated life is 10 years). ...
>
>This is why I asked:
>http://www.power-thru.com/documents/The%20Truth%20About%20Batteries%20-%20POWERTHRU%20White%20Paper.pdf
>
>"Many VRLA batteries are installed throughout the world and the
>industry is
>beginning to acknowledge that a 20 year VRLA battery life is unlikely
>to realize. Recent
>industry experience indicates that a 4 to 7 year VRLA battery life is
>more likely,
>regardless of cell size or warranty claims."
>
>"The data has shown us that so long as we control the temperature in
>our battery
>room, perform regular maintenance on our cells and install a quality
>battery in the
>first place, we should see our batteries last the design life of 5
>years (VRLA) 15
>years (Flooded), ..."
>
>Power-Thru sells flywheel UPS systems that reduce the peak demand on
>battery backups.
>
>An Interstate battery in my truck did last 17 years. I replaced it
>when its measured (carbon pile) discharge current fell uncomfortably
>close to the starter's cold weather demand.
>
>A few of my second-hand 12V,18A AGMs have failed from very low
>capacity in one cell. They appear normal on a top-up charge but
>rapidly drop to 10V during a load test.
>
>
>-jsw
>
I've been researching alternative batteries for the eventuality that
the current battery bank must be replaced. There is semi-local
(reasonable driving distance) vendor who has new Interstate Powercare
batteries (12MQ2400, 12 volt, 94AH [8 hour]) for $5 each (exchange).
I need to ask if he needs the exact battery or just a "core" of
similar weight. $90 to replace the entire battery bank would be a
very good price.
The single cell failure seems to be a common failure mode for small
VRLA batteries. I have several that died "in one cell" by the voltage
readings.
I've yet to try the "recover your AGM battery" process of opening the
battery up and adding water to the low cell. While I can see that it
might work in the short term, whatever caused that cell to fail is
still there and I'd expect it to fail again in the not-too-distant
future.
I've been spending the recent rainy days (4 days rain, 1 day not rain,
repeat) catching up on my fiction writing. I published my first
TEOTWAWKI novel a little over two years ago and have sold some 1700
copies. Probably OK for an unknown author's first book:
https://www.amazon.com/dp/B01LVU5ILA
I'll have two more books with a similar family theme on Amazon by the
end of this month.
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Posted by Jim Wilkins on January 5, 2019, 2:01 pm
<ads> wrote in message
> On Fri, 4 Jan 2019 12:41:49 -0500, "Jim Wilkins"
>
> ...
> I've yet to try the "recover your AGM battery" process of opening
> the
> battery up and adding water to the low cell. While I can see that
> it
> might work in the short term, whatever caused that cell to fail is
> still there and I'd expect it to fail again in the not-too-distant
> future.
>
Adding water didn't improve the one weak 12V,18A AGM I tried it on.
The valve caps were soft rubber and easy to remove.
My discharge test loads are an assortment of large rotary rheostats,
up to 1 Ohm 1000W (31A). Their advantage is a steady current that
doesn't confuse the ammeter with switching noise, the disadvantage is
that the intended constant current or power ramps down between
unevenly timed readjustments. Successive capacity measurements can
vary around +/- 10%, possibly due to this procedure, which obscures
small changes.
A DC-AC inverter makes a pretty good constant-power load with a
built-in but non adjustable low voltage cutoff. My crock pot draws
100W from the inverter without becoming dangerously hot, while the
rheostats approach 600F at their rated power. An inverter does produce
switching noise that seems to randomize the low voltage trip point.
The run time of an AC-powered refrigerator is hard to estimate because
the inverter will trip out on a starting surge voltage drop although
the battery could still provide the running current. My datalogger
uses PC-linked multimeters which can't sample faster than once per
second, and miss spikes. The DC Alpicool's ramped soft start is a help
here.
-jsw
Posted by Jim Wilkins on January 5, 2019, 2:15 pm
<ads> wrote in message
> On Fri, 4 Jan 2019 12:41:49 -0500, "Jim Wilkins"
>
>
> I've been spending the recent rainy days (4 days rain, 1 day not
> rain,
> repeat) catching up on my fiction writing. I published my first
> TEOTWAWKI novel a little over two years ago and have sold some 1700
> copies. Probably OK for an unknown author's first book:
> https://www.amazon.com/dp/B01LVU5ILA
>
So you live fairly close to "Neon" John DeArmond in Tellico Plains.
http://www.johndearmond.com/
Posted by ads on January 6, 2019, 1:43 am
On Sat, 5 Jan 2019 09:15:23 -0500, "Jim Wilkins"
><ads> wrote in message
>> On Fri, 4 Jan 2019 12:41:49 -0500, "Jim Wilkins"
>>
>>
>> I've been spending the recent rainy days (4 days rain, 1 day not
>> rain,
>> repeat) catching up on my fiction writing. I published my first
>> TEOTWAWKI novel a little over two years ago and have sold some 1700
>> copies. Probably OK for an unknown author's first book:
>> https://www.amazon.com/dp/B01LVU5ILA
>>
>
>So you live fairly close to "Neon" John DeArmond in Tellico Plains.
>http://www.johndearmond.com/
>
Not close, but almost due south - about 3 hours by road.
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Posted by Jim Wilkins on January 21, 2019, 3:56 pm
> On Thu, 3 Jan 2019 09:14:42 -0500, "Jim Wilkins"
>
>>Have you needed to replace AGMs yet? My experience with 12V18Ah AGMs
>>is that they deteriorate after around 5 years and can't be restored,
>>while flooded batteries are useable for at least 10 years if kept
>>charged.
>
> All my life I've had a reliable supply of telephone station
> batteries.
> I'd get them about the specified 10 year replacement and I'd get
> about
> 10 years' more use.
>
> With AGMs, the station change out is about 20 years and then I get
> another 20 years out of them.
>
> I have about 10 years into my current set of whole-house AGMs after
> their 20 years in the switch. I have a friend down from Nu Yawk
> Citi
> and one of out projects is to see what these have left using a
> commercial battery tester. I expect these to go the full 40 years
> again.
>
> John
> John DeArmond
> http://www.neon-john.com
> http://www.tnduction.com
> Tellico Plains, Occupied TN
> See website for email address
>
What does your commercial battery tester measure?
My experience is with industrial battery testers designed in-house,
mostly for Lithiums. They performed a time-consuming full discharge
and recharge cycle that recalibrates the battery pack's internal fuel
gauge. I haven't seen convincing evidence that the quicker DC or AC
impedance testers for lead-acids correlate well with remaining
capacity or service life.
-jsw
>> On Thu, 3 Jan 2019 09:14:42 -0500, "Jim Wilkins"
>>
>>>Have you needed to replace AGMs yet? My experience with 12V18Ah AGMs
>>>is that they deteriorate after around 5 years and can't be restored,
>>>while flooded batteries are useable for at least 10 years if kept
>>>charged.
>>>
>>>-jsw
>>>
>>
>> The AGMs were purchased used, a data center UPS changeout at 5 years
>> (rated life is 10 years). ...
>
>This is why I asked:
>http://www.power-thru.com/documents/The%20Truth%20About%20Batteries%20-%20POWERTHRU%20White%20Paper.pdf
>
>"Many VRLA batteries are installed throughout the world and the
>industry is
>beginning to acknowledge that a 20 year VRLA battery life is unlikely
>to realize. Recent
>industry experience indicates that a 4 to 7 year VRLA battery life is
>more likely,
>regardless of cell size or warranty claims."
>
>"The data has shown us that so long as we control the temperature in
>our battery
>room, perform regular maintenance on our cells and install a quality
>battery in the
>first place, we should see our batteries last the design life of 5
>years (VRLA) 15
>years (Flooded), ..."
>
>Power-Thru sells flywheel UPS systems that reduce the peak demand on
>battery backups.
>
>An Interstate battery in my truck did last 17 years. I replaced it
>when its measured (carbon pile) discharge current fell uncomfortably
>close to the starter's cold weather demand.
>
>A few of my second-hand 12V,18A AGMs have failed from very low
>capacity in one cell. They appear normal on a top-up charge but
>rapidly drop to 10V during a load test.
>
>
>-jsw
>