On Fri, 26 May 2017 10:21:39 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Wed, 24 May 2017 09:49:55 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
...
On Mon, 22 May 2017 18:39:59 -0400, "Jim Wilkins"
wrote:

...


I've had
some luck restoring a weak cell in a flooded battery and had popped
open that 12V 12AH AGM to add water, but it didn't appear to help
enough.

You added water to an AGM? How did you do that? And how had the
AGM
lost water?

I pried off the cover plate over the rubber caps, which pull off

I don't recall seeing covers on AGM cells, just small perfs.


easily. I don't know why some of the cells were dry. It's a
replacement from Batteries Plus I bought in 2009 to revive a dead UPS.
When new it delivered 82 Watt-hours; 12V times 12 Amp-hours is 144
Watt-hours, though only at or below the C/20 rate.

I measured computer run times on it a few times and plugged it in
occasionally to recharge. It wasn't on continuously because I had
changed from desktops to laptops that consume about 1/4 as much power
and serve as their own UPS, and after I found the free APC1400 and
rigged two external 105A-h batteries to it the small UPSs weren't
needed. In 2015 I noticed that its run time was very short and began
testing suggestions on how to salvage the battery.

I got about 7 minutes from my desktop UPS (450VA IIRC). The rest have
failed at the worst moments, NOT keeping my comp running when the
power went off. I've bought maybe 3x the number of batteries than I
have UPSes so far.


...
So "dead" batteries go into meltdown mode once they do finally start
accepting a charge? I see why most people have no success at it.
Even with the "save your battery" goo scam.

I suspect that pulse desulfators are a simple way to apply a high
enough voltage to break through sulfation while reliably limiting
current with capacitive and inductive impedance instead of active
control. Personally I prefer DC because an ammeter that reads
milliAmps shows how much the battery is improving, or not. My own
results and advice I've read suggest that a battery which needs over
17-18V applied before it accepts current can't be saved.

That's a lotta volts.


Dumb transformer + rectifier battery chargers have a moderate output
impedance that makes the current decrease as the voltage rises and
conversely increase as it drops, but not as sharply as a regulated
power supply.

The charger I was using then was an old manual 6 Amp Schauer with a
small 3 Amp Powerstat added to adjust for the current I wanted. The
current didn't change all that much as the voltage rose or fell, so
the battery didn't actually run away.

Ayup. That's safer.


A tightly regulated power supply could possibly let a battery run away
unless its current was limited by circuitry, its transformer or the
solar panel source such as the HF kit which is a good match to slow
battery reconditioning.

I like the current limiting in the cheapie 0-30.0v 0-3.00A Chiwanese
lab supply, and suppose I could get finer adjustment with a
milliammeter inline and the fine tune pot.


The power supply I built from a Variac and an arc welding transformer
has a relatively high output impedance to give the arc its constant
current characteristic, enough that the rectifier/cap output ripple at
20A is roughly a 1V sine wave. It puts out over 50V no load and drops
rapidly to around 35V as the current increases, with 120V AC in. The
output voltage then holds steadier up to around 25A out, its
experimentally determined 100% duty cycle limit. It will briefly
exceed 50A which is useful for testing components.

Nice and beefy!


As a 20A 24V battery charger it holds its output current quite steady
during the bulk charge phase but then becomes dangerous because it
won't automatically decrease the current enough when the battery
voltage rises to the gassing level. The simple fix is to pass the
output through a P20L or similar cheap solar controller set to reduce
the current when the voltage per battery reaches 13.6V. Light fizzing
that varies a little between cells becomes visible around 13.8V.

So, output from the PS to solar input terminals on the controller?
Unusual, but I guess it'd work, wouldn't it? Cool.


My two series-connected batteries, of different ages and sometimes
topped off to different levels, automatically self-balance to 13.6V
each on the APC1400's float charging current. Each has its own
voltmeter to watch that, also if one discharges faster.

Hooked up in series or parallel to charge? I don't know APC1400 specs
or setup.


I'm equalizing as gently as appears effective. The goal is to
determine if a variable voltage source with high resolution volt and
amp meters is enough to prolong and restore batteries IF operated
properly, which is the tricky part; the hardware is cheap except for
the Variacs that I already had.

I wish I'd grabbed the cheap Variac which was offered to me long
ago.

Cheap Variacs may need new brushes, which are far from cheap. I bought
a brass bar and some larger carbon brushes and machined my own
replacements because the right ones were out of stock. The original
brush geometry was too tricky to mill and assemble so I made the
brushes thicker and thus less fragile and will have to trim the end
contact width as they wear.
http://www.carbonbrush.com/brushes.htm

I nearly -ran- out of an electric shop once after getting a quote on
brushes. I guess they hate competition.


They use silver epoxy to glue in replacement carbons instead of
pressing tightly fitted ones in like the originals, and after pressing
mine in I understand why. I had better luck tediously cutting them to
size with a razor saw and files than milling them because they are so
brittle.

They _are_, aren't they? Nasty stuff to work with.


This isn't New Orleans; after a natural disaster the local
governments
quickly clean up and repair and only expect FEMA to arrive
afterwards
and write checks to cover the cost. My father was the CFO of one of
the state's departments that participated.

Interesting. Remember seeing the difference between OK after a
tornado and elitists in NY after a hurricane? Everyone came out to
help in OK, while elitists sat surrounded by mess and complained to
the Press about their blocks, all while not one single person came
out
to work to clean it up. Absolute night & day differences, wot?

NO: Save the city in a hole! Don't fill in the ground and bring it
above levee level so it never happens again, just put in bigger
pumps.
Crom, those folks are smart...not. I wonder what genetic strains
will
come from those folks now living where thousands of fracking ponds
(full of 600 different hazardous chemicals) were strewn by Katrina.
I tend to not buy anything from LA nowadays.


The dump trucks and loaders the towns need to clear snow can repair
flood washouts and push fallen trees off the roads, really
everything
except paving and building bridges. My one-week storm preparations
could stretch to two weeks but I don't think any longer is likely
with
the high level of response I've seen here.

Were I there, I'd have months worth of supplies for everything.

I think two weeks is probably enough in an area where people and local
governments have the tools to recover, though not in cities where
there's no place to run a generator. Germany and Japan kept their
societies functioning pretty normally until the very end.

Yeah, IF the local gov'ts do recover. What if the area is larger,
like the whole east coast? Prepping is truly cheap, compared to the
alternative.


I assume my biggest need will be roof repair to prevent further
damage. When a fallen tree top punctured my roof in over a dozen
places I quickly covered the holes with sheet metal shoved under the
shingles at the upper end. I lost the shiny finish on my 6061 aluminum
but saved the house from water. Plywood covered with a large tarp
would also have worked, unless everyone else had the same idea and the
stores were empty. I happen to have the machines to work sheetmetal
and the need to make electronic enclosures.

That's why I took most of my trees down. I'd rather my house not be a
target, thanks.


When Jay Leno asked New Yorker actress Lea Michelle how she handled TS
Sandy she told him she didn't even own a flashlight. In my Mensa
experience that's fairly typical of the complete dependency they
accept as natural, can't change and don't think about. Let the good
times roll.

sigh Luckily, nature accepts the survival only of the fittest.
But the rich folks' armed bodyguards might take things from others if
others aren't careful.

--
I started out with nothing and
I still have most of it left!
--anon