I've finally acquired enough equipment to measure the remaining
Amp-Hour capacity of my Lead-Acid and Lithium battery collection. The
first result that jumped out is that older batteries suffer from
rising internal resistance as they discharge, enough that the
automatic low voltage cutoff trips short of rated capacity, and then
the battery slowly recovers to well above the full discharge voltage
given in the specs.

http://www.power-sonic.com/images/po...hManual-Lo.pdf

The 5-year-old 12v 4.5Ah UPS battery I tested this AM delivered 2.45Ah
at 3A, which is the average current my laptop draws while browsing.
Table 2 shows in the 1 Hour Rate column that it should be good for
2.75Ah at 2.75A current.

Does anyone know a good reason why I can't measure the true remaining
capacity in two steps by first discharging to 10V at the fairly high
current of my typical loads, then continuing at the 20 hour rate AGM
batteries are specified for until the voltage drops to [the
appropriate endpoint] again?

The run time for a typical load tells me how useful the battery still
is, but it combines the effects of capacity and resistance. I'm
wondering if also knowing the Amp-Hour capacity at the 20 hour rate,
with less interference from the internal resistance, would indicate
how well my long-term maintenance procedures work.

-jsw

"Jim Wilkins" wrote in message
news

The 5-year-old 12v 4.5Ah UPS battery I tested this AM delivered
2.45Ah at 3A, which is the average current my laptop draws while
browsing. Table 2 shows in the 1 Hour Rate column that it should be
good for 2.75Ah at 2.75A current.

-jsw

That wasn't a good example. I have a 12V 12Ah AGM battery that is down
to 1 useful Amp-hour because its voltage droops to 10V so quickly.
Afterwards it recovers above 12.2V.
-jsw

On Friday, May 19, 2017 at 12:33:52 PM UTC-4, Jim Wilkins wrote:
I've finally acquired enough equipment to measure the remaining
Amp-Hour capacity of my Lead-Acid and Lithium battery collection. The
first result that jumped out is that older batteries suffer from
rising internal resistance as they discharge, enough that the
automatic low voltage cutoff trips short of rated capacity, and then
the battery slowly recovers to well above the full discharge voltage
given in the specs.

http://www.power-sonic.com/images/po...hManual-Lo.pdf

The 5-year-old 12v 4.5Ah UPS battery I tested this AM delivered 2.45Ah
at 3A, which is the average current my laptop draws while browsing.
Table 2 shows in the 1 Hour Rate column that it should be good for
2.75Ah at 2.75A current.

Does anyone know a good reason why I can't measure the true remaining
capacity in two steps by first discharging to 10V at the fairly high
current of my typical loads, then continuing at the 20 hour rate AGM
batteries are specified for until the voltage drops to [the
appropriate endpoint] again?

The run time for a typical load tells me how useful the battery still
is, but it combines the effects of capacity and resistance. I'm
wondering if also knowing the Amp-Hour capacity at the 20 hour rate,
with less interference from the internal resistance, would indicate
how well my long-term maintenance procedures work.

-jsw

I think that doing the 20 hour test my provide you with academic indication of the condition of the batteries, but only at the 20 hour rate. In my recollection (based on 25 years ago designing a 100 station lead acid charger), there is surprisingly little correlation between capacity at different discharge rates.

So, I would suggest you test at your normal load and perhaps with a "normal minimum load" assuming that those rates are pretty far from 20 hours. Anything else is, as I said, purely academic.

BTW, while I was buying the voltage reference, I also bought a USB power meter (Drok). The Amazon add and the user's manual keep referring to "capacitance" measurement. What they really mean is capacity of USB battery packs. Pretty funny. Sort of. You can actually buy this meter bundled with a USB load bank.

"rangerssuck" wrote in message
...
On Friday, May 19, 2017 at 12:33:52 PM UTC-4, Jim Wilkins wrote:
I've finally acquired enough equipment to measure the remaining
Amp-Hour capacity of my Lead-Acid and Lithium battery collection.
The
first result that jumped out is that older batteries suffer from
rising internal resistance as they discharge, enough that the
automatic low voltage cutoff trips short of rated capacity, and then
the battery slowly recovers to well above the full discharge voltage
given in the specs.

http://www.power-sonic.com/images/po...hManual-Lo.pdf

The 5-year-old 12v 4.5Ah UPS battery I tested this AM delivered
2.45Ah
at 3A, which is the average current my laptop draws while browsing.
Table 2 shows in the 1 Hour Rate column that it should be good for
2.75Ah at 2.75A current.

Does anyone know a good reason why I can't measure the true
remaining
capacity in two steps by first discharging to 10V at the fairly high
current of my typical loads, then continuing at the 20 hour rate AGM
batteries are specified for until the voltage drops to [the
appropriate endpoint] again?

The run time for a typical load tells me how useful the battery
still
is, but it combines the effects of capacity and resistance. I'm
wondering if also knowing the Amp-Hour capacity at the 20 hour rate,
with less interference from the internal resistance, would indicate
how well my long-term maintenance procedures work.

-jsw

I think that doing the 20 hour test my provide you with academic
indication of the condition of the batteries, but only at the 20 hour
rate. In my recollection (based on 25 years ago designing a 100
station lead acid charger), there is surprisingly little correlation
between capacity at different discharge rates.

So, I would suggest you test at your normal load and perhaps with a
"normal minimum load" assuming that those rates are pretty far from 20
hours. Anything else is, as I said, purely academic.

BTW, while I was buying the voltage reference, I also bought a USB
power meter (Drok). The Amazon add and the user's manual keep
referring to "capacitance" measurement. What they really mean is
capacity of USB battery packs. Pretty funny. Sort of. You can actually
buy this meter bundled with a USB load bank.

=========================

I want to separate the effects of capacity and internal resistance to
see if equalizing etc improves either or both of them. The internal
resistance of AGMs has some strangely behaved component reputedly
related to an oxide film. Otherwise I discharge them at the current my
laptop draws when browsing as I have them for power-outage backup and
NWS radar is the best indication of storms approaching my house that
I've found. It tells me when to repair roof damage and when to tarp
it.

I bought this which has an easily set low voltage disconnect and
handles up to +/-30A,
https://www.amazon.com/DROK-Display-...ct_top?ie=UTF8

and previously this which is 10x as accurate at low current
https://www.amazon.com/bayite-Multif.../dp/B01D7JGGE4

The first one measures charge and discharge current separately and
counts the Amp-hours up or down accordingly, though the Watt-hours
total is the positive sum of both (???). It has a more accurate
voltmeter and a better timer that counts seconds and stops when the
relay opens, allowing a pause in the measurement and a record of
battery run time. Unfortunately the current resolution is 0.1A despite
the display, so it doesn't handle small AGMs well.

The second one matches other ammeters to 1 or 2 digits and I use both
in series for discharge loads up to 10A. Together they each make up
for the deficiencies of the other. The 12V,12Ah battery is discharging
on them at 0.5A.
-jsw

"Jim Wilkins" wrote in message
news

"rangerssuck" wrote in message
...
I think that doing the 20 hour test my provide you with academic
indication of the condition of the batteries, but only at the 20
hour rate. In my recollection (based on 25 years ago designing a 100
station lead acid charger), there is surprisingly little correlation
between capacity at different discharge rates.


I've read that repeated capacity tests on the same battery don't
correlate well.

On 5/19/2017 9:33 AM, Jim Wilkins wrote:
I've finally acquired enough equipment to measure the remaining
Amp-Hour capacity of my Lead-Acid and Lithium battery collection. The
first result that jumped out is that older batteries suffer from
rising internal resistance as they discharge, enough that the
automatic low voltage cutoff trips short of rated capacity, and then
the battery slowly recovers to well above the full discharge voltage
given in the specs.

http://www.power-sonic.com/images/po...hManual-Lo.pdf

The 5-year-old 12v 4.5Ah UPS battery I tested this AM delivered 2.45Ah
at 3A, which is the average current my laptop draws while browsing.
Table 2 shows in the 1 Hour Rate column that it should be good for
2.75Ah at 2.75A current.

Does anyone know a good reason why I can't measure the true remaining
capacity in two steps by first discharging to 10V at the fairly high
current of my typical loads, then continuing at the 20 hour rate AGM
batteries are specified for until the voltage drops to [the
appropriate endpoint] again?

The run time for a typical load tells me how useful the battery still
is, but it combines the effects of capacity and resistance. I'm
wondering if also knowing the Amp-Hour capacity at the 20 hour rate,
with less interference from the internal resistance, would indicate
how well my long-term maintenance procedures work.

-jsw


I gave up. Never got any predictive information.

Most of my testing was done with Lithium batteries in laptops.

I consider a laptop battery bad when it won't run the laptop
long enough. How vague is that? ;-)

Started with bad battery packs and tested cells.
At low current, I almost always got something like specified
capacity. The electrons are in there, but the laptop won't
let you have them.

I don't know what the sampling interval is, but the laptop
wants to shut down at some voltage so you don't lose data
and call the vendor. Subtract the peak voltage across the ESR
from the battery voltage. If it dips below the threshold,
the laptop wants to shut down.

Turn off the power features that warn of impending low voltage
shutdown.

The symptom is that the battery gauge decays slowly for a while
then drops instantly to a much lower number. The laptop senses
impending doom, but you've blocked that.
I've had laptops run two hours past the point when the battery
gauge hit zero. Problem is that when it dies, you lose whatever
you were working on.

I've never had any success trying to fix the ESR. That's probably
the same problem you have when your car fails to start. Never been
able to do anything about that either.

The higher the peak current, the fewer electrons all those
protection circuits will let you have.
Even with a new battery, capacity is a strong function of
load current.

Numbers from browsing the web won't help much when
Microsoft decides to do an update and runs all your cores
at 100%.

On 2017-05-19, mike wrote:
On 5/19/2017 9:33 AM, Jim Wilkins wrote:
I've finally acquired enough equipment to measure the remaining
Amp-Hour capacity of my Lead-Acid and Lithium battery collection. The
first result that jumped out is that older batteries suffer from
rising internal resistance as they discharge, enough that the
automatic low voltage cutoff trips short of rated capacity, and then
the battery slowly recovers to well above the full discharge voltage
given in the specs.

[ ... ]

The higher the peak current, the fewer electrons all those
protection circuits will let you have.
Even with a new battery, capacity is a strong function of
load current.

Numbers from browsing the web won't help much when
Microsoft decides to do an update and runs all your cores
at 100%.

Well ... that is not a problem for me. The first thing I do
when I pick up a new (to me) laptop is to remove the virus. The last
virus was called "Windows 10". I replace it with either a linux or an
OpenBSD system, so Microsoft doesn't have a say in when I update, and
updates for the others are based on telling me that updates are
available, and letting me decide whether and when to install them. :-)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"mike" wrote in message
news
On 5/19/2017 9:33 AM, Jim Wilkins wrote:
...
The symptom is that the battery gauge decays slowly for a while
then drops instantly to a much lower number. The laptop senses
impending doom, but you've blocked that.
I've had laptops run two hours past the point when the battery
gauge hit zero. Problem is that when it dies, you lose whatever
you were working on.
...

The "fuel gauge" IC counts Coulombs in and out to determine actual
Lithium battery capacity, on the assumption that they recharge at 100%
efficiency. It resets its capacity estimate if the battery is nearly
fully discharged and recharged, but if only partly discharged it can't
detect the slow loss of capacity with age and retains the old, overly
optimistic number from the last full cycle. That's why the sudden jump
when it realizes it's wrong.

When you give the battery another full cycle it can measure and update
the battery capacity to its new, lower value.

As an experiment I reduced the low voltage trip as far as possible and
got almost as much run time from an old Dell battery below the 5%
level as from 100% to 5%. It appears that Li-Ion cells can be
discharged down to or even below 2.7V briefly without much damage. The
normal settings are above 3.0V.
http://batteryuniversity.com/learn/a...oltage_cut_off

This gives you the battery voltage:
https://www.hwinfo.com/

-jsw

On Fri, 19 May 2017 16:13:34 -0400, "Jim Wilkins"
wrote:


"rangerssuck" wrote in message
...
On Friday, May 19, 2017 at 12:33:52 PM UTC-4, Jim Wilkins wrote:
I've finally acquired enough equipment to measure the remaining
Amp-Hour capacity of my Lead-Acid and Lithium battery collection.
The
first result that jumped out is that older batteries suffer from
rising internal resistance as they discharge, enough that the
automatic low voltage cutoff trips short of rated capacity, and then
the battery slowly recovers to well above the full discharge voltage
given in the specs.

http://www.power-sonic.com/images/po...hManual-Lo.pdf

The 5-year-old 12v 4.5Ah UPS battery I tested this AM delivered
2.45Ah
at 3A, which is the average current my laptop draws while browsing.
Table 2 shows in the 1 Hour Rate column that it should be good for
2.75Ah at 2.75A current.

Does anyone know a good reason why I can't measure the true
remaining
capacity in two steps by first discharging to 10V at the fairly high
current of my typical loads, then continuing at the 20 hour rate AGM
batteries are specified for until the voltage drops to [the
appropriate endpoint] again?

The run time for a typical load tells me how useful the battery
still
is, but it combines the effects of capacity and resistance. I'm
wondering if also knowing the Amp-Hour capacity at the 20 hour rate,
with less interference from the internal resistance, would indicate
how well my long-term maintenance procedures work.

-jsw

I think that doing the 20 hour test my provide you with academic
indication of the condition of the batteries, but only at the 20 hour
rate. In my recollection (based on 25 years ago designing a 100
station lead acid charger), there is surprisingly little correlation
between capacity at different discharge rates.

So, I would suggest you test at your normal load and perhaps with a
"normal minimum load" assuming that those rates are pretty far from 20
hours. Anything else is, as I said, purely academic.

BTW, while I was buying the voltage reference, I also bought a USB
power meter (Drok). The Amazon add and the user's manual keep
referring to "capacitance" measurement. What they really mean is
capacity of USB battery packs. Pretty funny. Sort of. You can actually
buy this meter bundled with a USB load bank.

=========================

I want to separate the effects of capacity and internal resistance to
see if equalizing etc improves either or both of them. The internal
resistance of AGMs has some strangely behaved component reputedly
related to an oxide film. Otherwise I discharge them at the current my
laptop draws when browsing as I have them for power-outage backup and
NWS radar is the best indication of storms approaching my house that
I've found. It tells me when to repair roof damage and when to tarp
it.

I bought this which has an easily set low voltage disconnect and
handles up to +/-30A,
https://www.amazon.com/DROK-Display-...ct_top?ie=UTF8

Hmm, there are 3 different pictures of the back of those. One has a
built-in shunt, another a pair of relays, and another is bare. Which
is the real meter pic for the "30a w/ relay"?


and previously this which is 10x as accurate at low current
https://www.amazon.com/bayite-Multif.../dp/B01D7JGGE4

IF I ever get the weeding done around here, I'll get those panels up
and build the control panel to see how those li'l Bayites work.
You showed another link for a milliamp/millivolt-resolution meter a
few weeks ago, too. How's that working for you?


The first one measures charge and discharge current separately and
counts the Amp-hours up or down accordingly, though the Watt-hours
total is the positive sum of both (???). It has a more accurate
voltmeter and a better timer that counts seconds and stops when the
relay opens, allowing a pause in the measurement and a record of
battery run time. Unfortunately the current resolution is 0.1A despite
the display, so it doesn't handle small AGMs well.

The former part is cool. Not having proper resolution for decent data
is never fun, though.


The second one matches other ammeters to 1 or 2 digits and I use both
in series for discharge loads up to 10A. Together they each make up
for the deficiencies of the other. The 12V,12Ah battery is discharging
on them at 0.5A.

Did I ever ask you why you didn't use a real battery for that? g
(real being 12v 35-275Ah) I set one up for use with the 45w HF trio
of panels and was able to power a 14" electric chainsaw with the 2kW
modified sine wave inverter, also from HF. It would have taken days
to recharge it (or more panels if needed for continued use.)

--
In today’s academia and mainstream media,
we’re all guilty of hate until proven leftist.

--Robert Knight, senior fellow, American Civil Rights Union

"Larry Jaques" wrote in message
news
On Fri, 19 May 2017 16:13:34 -0400, "Jim Wilkins"
wrote:

....................

I bought this which has an easily set low voltage disconnect and
handles up to +/-30A,
https://www.amazon.com/DROK-Display-...ct_top?ie=UTF8

Hmm, there are 3 different pictures of the back of those. One has a
built-in shunt, another a pair of relays, and another is bare.
Which
is the real meter pic for the "30a w/ relay"?

The 30A model I received has a shunt and blue NC relay on the base
module. The display module has a small red+black pigtail for external
power if you don't use a USB connection. At first the USB connection
on mine was poor and it intermittently shut off, or switched to
wireless without losing power. The correct accumulated totals
reappeared when it reconnected.

It displays current to 2 decimal places but is accurate only to 1
place +/-, for example 0.478A on a Fluke 8600A reads as 0.48A on the
10A "Electrical Parameter Tester", and 0.65A on the 30A unit.

A layer of Gorilla tape tightened the USB plug in the base unit
against the circuit board contacts and it has remained connected when
moved.

You showed another link for a milliamp/millivolt-resolution meter a
few weeks ago, too. How's that working for you?

The 33.00V/3.000A meter is my favorite for recharging and equalizing
batteries slowly from my solar panels. It clearly shows when a small
AGM's charging current has decreased to 1% of the C/20 capacity, like
45mA for a 4.5A-h AGM battery. Currents around 1% are recommended end
points for trickle charging.
http://www.trojanbattery.com/pdf/Tro...UsersGuide.pdf
Diagram 4 gives 1-3% for flooded, Diagram 5 gives 0.5% for AGM.

As mentioned, the current rises in older batteries and is an indicator
of declining condition.

The first one measures charge and discharge current separately and
counts the Amp-hours up or down accordingly, though the Watt-hours
total is the positive sum of both (???). It has a more accurate
voltmeter and a better timer that counts seconds and stops when the
relay opens, allowing a pause in the measurement and a record of
battery run time. Unfortunately the current resolution is 0.1A
despite
the display, so it doesn't handle small AGMs well.

The former part is cool. Not having proper resolution for decent
data
is never fun, though.

I first learned how to make accurate measurements as a chemist whose
results might have to stand up in court, then when building very
precise automatic test equipment for the semiconductor industry.
Analog Devices' op amps and voltage regulators were tested on machines
whose performance I was responsible for.
https://en.wikipedia.org/wiki/Automatic_test_equipment

The second one matches other ammeters to 1 or 2 digits and I use
both
in series for discharge loads up to 10A. Together they each make up
for the deficiencies of the other. The 12V,12Ah battery is
discharging
on them at 0.5A.

Did I ever ask you why you didn't use a real battery for that? g
(real being 12v 35-275Ah) I set one up for use with the 45w HF trio
of panels and was able to power a 14" electric chainsaw with the 2kW
modified sine wave inverter, also from HF. It would have taken days
to recharge it (or more panels if needed for continued use.)

I do have "real" batteries that will run the fridge for about 20
hours. Once I'm satisfied with my discharge testing setup I'll get to
them. For now I'm testing and risking smaller, older, less valuable
jumpstarter and UPS AGMs. These tests are too long to watch and if the
low voltage disconnect fails the battery could be drained flat before
I notice.
-jsw

"Jim Wilkins" wrote in message
news
"Larry Jaques" wrote in message
news
On Fri, 19 May 2017 16:13:34 -0400, "Jim Wilkins"
wrote:

....................

I bought this which has an easily set low voltage disconnect and
handles up to +/-30A,
https://www.amazon.com/DROK-Display-...ct_top?ie=UTF8


Previously I was using a rewired Battery Isolator I bought from
Quicksilver Radio for $5 at a hamfest to disconnect the load when the
voltage dropped. This describes the idea:
http://www.fridge-and-solar.net/The-...-Start-VSR.htm

The rewiring changed it from switching the load to the second battery
when the main one's voltage dropped to switching one battery from the
load to a charger.

As a discharge controller it has the disadvantages of still drawing
current from the main battery to operate the relay after it has
discharged to the disconnect voltage, and needing an adjustable power
supply to set or check it.

I haven't seen that remaining for an hour or so at full discharge
would further harm a battery and want to record the voltage it
recovers to without any load as an indication of true remaining
capacity and a safety check that I haven't set the disconnect voltage
too low and drained the battery too far.

If not for its poor current resolution the 30A Drok unit would be a
fine discharge test controller when powered from an external 12V
supply that separates its operating current from the test circuit. The
circuit board was drilled but not properly connected for an SPDT
version of the SPST NC relay it comes with. I'll set the Battery
Isolator to a lower disconnect voltage as a backup on the load side of
the Drok.

Based on Amazon comments, it seems the 3-wire / 2-wire jumper may
select battery circuit or external power to operate the device.

A DC-AC inverter powering a safe resistive load like a crockpot can be
used as a discharge test load though you can't set the dropout voltage
and it may cycle back on when the battery recovers.
-jsw

On Sun, 21 May 2017 19:49:32 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
news
On Fri, 19 May 2017 16:13:34 -0400, "Jim Wilkins"
wrote:

....................

I bought this which has an easily set low voltage disconnect and
handles up to +/-30A,
https://www.amazon.com/DROK-Display-...ct_top?ie=UTF8

Hmm, there are 3 different pictures of the back of those. One has a
built-in shunt, another a pair of relays, and another is bare.
Which
is the real meter pic for the "30a w/ relay"?

The 30A model I received has a shunt and blue NC relay on the base
module. The display module has a small red+black pigtail for external
power if you don't use a USB connection. At first the USB connection
on mine was poor and it intermittently shut off, or switched to
wireless without losing power. The correct accumulated totals
reappeared when it reconnected.

It displays current to 2 decimal places but is accurate only to 1
place +/-, for example 0.478A on a Fluke 8600A reads as 0.48A on the
10A "Electrical Parameter Tester", and 0.65A on the 30A unit.

A layer of Gorilla tape tightened the USB plug in the base unit
against the circuit board contacts and it has remained connected when
moved.

Duct tape to the rescue again.


You showed another link for a milliamp/millivolt-resolution meter a
few weeks ago, too. How's that working for you?

The 33.00V/3.000A meter is my favorite for recharging and equalizing
batteries slowly from my solar panels. It clearly shows when a small
AGM's charging current has decreased to 1% of the C/20 capacity, like
45mA for a 4.5A-h AGM battery. Currents around 1% are recommended end
points for trickle charging.
http://www.trojanbattery.com/pdf/Tro...UsersGuide.pdf
Diagram 4 gives 1-3% for flooded, Diagram 5 gives 0.5% for AGM.

I've downloaded both guides you've mentioned in the past several days
and will have to compare them. Each one will have tidbits of info the
other doesn't. That's the true benefit of research: gleaning tidbits.


As mentioned, the current rises in older batteries and is an indicator
of declining condition.

That sounds like something I should pay attention to.


The first one measures charge and discharge current separately and
counts the Amp-hours up or down accordingly, though the Watt-hours
total is the positive sum of both (???). It has a more accurate
voltmeter and a better timer that counts seconds and stops when the
relay opens, allowing a pause in the measurement and a record of
battery run time. Unfortunately the current resolution is 0.1A
despite
the display, so it doesn't handle small AGMs well.

The former part is cool. Not having proper resolution for decent
data
is never fun, though.

I first learned how to make accurate measurements as a chemist whose
results might have to stand up in court, then when building very
precise automatic test equipment for the semiconductor industry.
Analog Devices' op amps and voltage regulators were tested on machines
whose performance I was responsible for.
https://en.wikipedia.org/wiki/Automatic_test_equipment

Cool! Nice legacy.


The second one matches other ammeters to 1 or 2 digits and I use
both
in series for discharge loads up to 10A. Together they each make up
for the deficiencies of the other. The 12V,12Ah battery is
discharging
on them at 0.5A.

I forgot to ask what you meant by that. Are they drawing half an amp
or showing that discharge rate?


Did I ever ask you why you didn't use a real battery for that? g
(real being 12v 35-275Ah) I set one up for use with the 45w HF trio
of panels and was able to power a 14" electric chainsaw with the 2kW
modified sine wave inverter, also from HF. It would have taken days
to recharge it (or more panels if needed for continued use.)

I do have "real" batteries that will run the fridge for about 20
hours. Once I'm satisfied with my discharge testing setup I'll get to
them. For now I'm testing and risking smaller, older, less valuable
jumpstarter and UPS AGMs.

Smart.


These tests are too long to watch and if the
low voltage disconnect fails the battery could be drained flat before
I notice.

That wouldn't be fun. How often do the disconnect programs (or
hardware/relays) fail?

--
In today’s academia and mainstream media,
we’re all guilty of hate until proven leftist.

--Robert Knight, senior fellow, American Civil Rights Union

"Larry Jaques" wrote in message
news
On Sun, 21 May 2017 19:49:32 -0400, "Jim Wilkins"
wrote:

..................
http://www.trojanbattery.com/pdf/Tro...UsersGuide.pdf
Diagram 4 gives 1-3% for flooded, Diagram 5 gives 0.5% for AGM.

I've downloaded both guides you've mentioned in the past several
days
and will have to compare them. Each one will have tidbits of info
the
other doesn't. That's the true benefit of research: gleaning
tidbits.


As mentioned, the current rises in older batteries and is an
indicator
of declining condition.

That sounds like something I should pay attention to.

I suspect it means that the self-discharge rate has increased and they
may need more frequent topping off. I don't know how it relates to
remaining capacity.


The second one matches other ammeters to 1 or 2 digits and I use
both
in series for discharge loads up to 10A. Together they each make
up
for the deficiencies of the other. The 12V,12Ah battery is
discharging
on them at 0.5A.

I forgot to ask what you meant by that. Are they drawing half an
amp
or showing that discharge rate?

I kept the current from the battery close to 0.5A by tweaking the
rheostat load. Surplus phone chargers power the meters and the relay
independently from the battery, since I won't be wasting my backup by
running these discharge tests into a dummy load during a power outage.

Some of my homebrew test equipment runs on AC power for better
accuracy, some on DC from the battery being tested or the solar panels
so it will still show demand or charging rate during a power outage.
The load current varies too much for accurate measurement and battery
remaining life prediction, but all I really need to know is if the
batteries can run the fridge overnight.

The box whose components I tested this morning will have a switch for
internal or external power. The meters have to be on external power to
measure single 18650 Lithiums to their discharge endpoint which is
below the minimum supply voltage..

The two of these I bought match the Fluke 8800A to 1mV. YMMV.
https://www.amazon.com/DROK-Digital-.../dp/B01BXZNK0C

Did I ever ask you why you didn't use a real battery for that? g
(real being 12v 35-275Ah) I set one up for use with the 45w HF
trio
of panels and was able to power a 14" electric chainsaw with the
2kW
modified sine wave inverter, also from HF. It would have taken
days
to recharge it (or more panels if needed for continued use.)

I do have "real" batteries that will run the fridge for about 20
hours. Once I'm satisfied with my discharge testing setup I'll get
to
them. For now I'm testing and risking smaller, older, less valuable
jumpstarter and UPS AGMs.

Smart.


These tests are too long to watch and if the
low voltage disconnect fails the battery could be drained flat
before
I notice.

That wouldn't be fun. How often do the disconnect programs (or
hardware/relays) fail?

How often do brakes fail?

On Mon, 22 May 2017 08:34:11 -0400, "Jim Wilkins"
wrote:

"Jim Wilkins" wrote in message
news
"Larry Jaques" wrote in message
news
On Fri, 19 May 2017 16:13:34 -0400, "Jim Wilkins"
wrote:

....................

I bought this which has an easily set low voltage disconnect and
handles up to +/-30A,
https://www.amazon.com/DROK-Display-...ct_top?ie=UTF8


Previously I was using a rewired Battery Isolator I bought from
Quicksilver Radio for $5 at a hamfest to disconnect the load when the
voltage dropped. This describes the idea:
http://www.fridge-and-solar.net/The-...-Start-VSR.htm

Great price!


The rewiring changed it from switching the load to the second battery
when the main one's voltage dropped to switching one battery from the
load to a charger.

Discharge in series? Sounds like a plan.


As a discharge controller it has the disadvantages of still drawing
current from the main battery to operate the relay after it has
discharged to the disconnect voltage, and needing an adjustable power
supply to set or check it.

Those I've seen only engage the relay to switch to the secondary
battery. Are you talking about when the secondary battery is
discharged/cutoff and the relay continuing to be engaged? I see that
as a problem, too. Perhaps rig up a kickout relay to disengage when
the cutoff hits on the secondary?


I haven't seen that remaining for an hour or so at full discharge
would further harm a battery and want to record the voltage it
recovers to without any load as an indication of true remaining
capacity and a safety check that I haven't set the disconnect voltage
too low and drained the battery too far.

Yeah, that's a fly in the ointment of capacity measurement. Are you
saying "full discharge to cutoff point" there?


If not for its poor current resolution the 30A Drok unit would be a
fine discharge test controller when powered from an external 12V
supply that separates its operating current from the test circuit. The
circuit board was drilled but not properly connected for an SPDT
version of the SPST NC relay it comes with. I'll set the Battery
Isolator to a lower disconnect voltage as a backup on the load side of
the Drok.

There ya go!


Based on Amazon comments, it seems the 3-wire / 2-wire jumper may
select battery circuit or external power to operate the device.

It didn't look like that was fully populated in the pic I saw. IIRC,
it had only one pin/solder joint out of the 3.


A DC-AC inverter powering a safe resistive load like a crockpot can be
used as a discharge test load though you can't set the dropout voltage
and it may cycle back on when the battery recovers.

Hmm, yeah.

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

"Larry Jaques" wrote in message
...
On Mon, 22 May 2017 08:34:11 -0400, "Jim Wilkins"
wrote:
...
Previously I was using a rewired Battery Isolator I bought from
Quicksilver Radio for $5 at a hamfest ...
....
Those I've seen only engage the relay to switch to the secondary
battery. Are you talking about when the secondary battery is
discharged/cutoff and the relay continuing to be engaged? I see
that
as a problem, too. Perhaps rig up a kickout relay to disengage when
the cutoff hits on the secondary?

This one remains powered by the main battery when it switches the load
to the second one, perhaps to avoid the glitch while the
break-before-make relay contact is moving. It drives the relay with an
SCR and won't release and revert to the main battery until the user
pushes a disconnect button, regardless of how high the main battery
may have recovered or been recharged. This means that connecting NO to
a charger won't make the relay turn off when the battery voltage
rises.

I cut and jumpered the traces to redefine COM as the battery instead
of the load, which is now NC. Originally COM was the load, NC the main
battery and NO the secondary one. As you said it would simply allow
the secondary battery to die, but retain whatever capacity the trip
point left in the main battery.

Maybe running the anchor light as long as possible is more important
than preserving a battery that sinks when the boat is hit?

I haven't seen that remaining for an hour or so at full discharge
would further harm a battery and want to record the voltage it
recovers to without any load as an indication of true remaining
capacity and a safety check that I haven't set the disconnect
voltage
too low and drained the battery too far.

Yeah, that's a fly in the ointment of capacity measurement. Are you
saying "full discharge to cutoff point" there?

Here's the problem:
http://batteryuniversity.com/learn/a...tate_of_charge
"To get accurate readings, the battery needs to rest in the open
circuit state for at least four hours..."

The AGM I discharged at a little less than the 20 hour rate (0.5A)
tripped at 10.0V (twice) and then recovered to 12.15V, which is over
40% State-of-Charge on that chart.

The point of knowing the full capacity is to find out why I'm not
getting it, and see if anything I can do makes an improvement. I can't
fix bad interconnects but a discharge - charge - equalize cycle
reforms the active material. Only measurements will show how well
equalizing and desulfating work. I know I can make them last much
longer than usual, but is it worth the effort?

-jsw

"Jim Wilkins" wrote in message
news
http://batteryuniversity.com/learn/a...nal_resistance
The two-tier DC load method is how the engineer had me test electric
vehicle Lithiums, using a programmable electronic load and a much
better DC current probe than I'll probably ever own personally.
-jsw

On 5/22/2017 9:34 AM, Jim Wilkins wrote:


I kept the current from the battery close to 0.5A by tweaking the
rheostat load. Surplus phone chargers power the meters and the relay
independently from the battery, since I won't be wasting my backup by
running these discharge tests into a dummy load during a power outage.


One consideration for backup is the cost of failure.
if the worst that can happen is a gallon of milk has shortened shelf life,
that's a lot less serious than a mechanical fridge compressor that
stalls when it tries to start under brownout conditions.

If you're serious about these kinds of measurements, wire up
a LM317 (maybe with a booster transistor) as a current load.

If the voltage doesn't vary too much, an incandescent light bulb
makes a current source that's more stable than a resistor.

A computer controlled dual-output power supply is a useful tool.
Use one output to charge the battery and read back the voltage.
Use the other output to drive a voltage to current converter for the load.
Makes it very easy to control and log and graph and...

If I had a solar system, I'd have an arduino or some such
monitoring it at all times.

I have a Palm Pilot monitoring the HVAC system.
Had the installer come fix it before it quit completely.

"mike" wrote in message
news
On 5/22/2017 9:34 AM, Jim Wilkins wrote:


I kept the current from the battery close to 0.5A by tweaking the
rheostat load. Surplus phone chargers power the meters and the
relay
independently from the battery, since I won't be wasting my backup
by
running these discharge tests into a dummy load during a power
outage.


One consideration for backup is the cost of failure.
if the worst that can happen is a gallon of milk has shortened shelf
life,
that's a lot less serious than a mechanical fridge compressor that
stalls when it tries to start under brownout conditions.

I'm more concerned with being able to replace the lost food after a
hurricane or ice storm when the roads are blocked by fallen trees
tangled in possibly live power lines (generator backfeed) and the
stores don't have power either. The area I'm in typically stays dark
for a week before the line crews get to us.
https://en.wikipedia.org/wiki/Decemb...ates_ice_storm

If you're serious about these kinds of measurements, wire up
a LM317 (maybe with a booster transistor) as a current load.

If the voltage doesn't vary too much, an incandescent light bulb
makes a current source that's more stable than a resistor.

A computer controlled dual-output power supply is a useful tool.
Use one output to charge the battery and read back the voltage.
Use the other output to drive a voltage to current converter for the
load.
Makes it very easy to control and log and graph and...

I had very nice, and expensive, equipment like that when I was the
battery tech at Segway. While running the tests I found out what was
important and what wasn't, and saw that I could obtain adequate
results at home with much cheaper surplus equipment like old Ohmite
rotary rheostats. Tubular variable resistors are difficult to adjust
when hot, around 600F near their rated power.

The only time I programmed a load to change automatically was for
two-level battery impedance measurements. Otherwise the voltages and
currents remained constant until I changed them, which can be done as
easily with a knob. We used our lab power supplies to recharge vendor
sample Lithium cells to the appropriate voltage at a constant current.

The best representation of a real-life active load isn't constant
resistance or current but constant power such as a DC-AC inverter
draws, and I can just use one with a hotplate on a Variac for the
adjustable load. Inverters usually have a functioning low voltage
disconnect to protect the battery. However a fixed resistance load is
fine for tracking battery ageing and easier than a switching load to
measure accurately.

These connected to a laptop make a good data acquisition system for
slowly changing parameters like battery voltage.
https://www.amazon.com/Tekpower-TP40.../dp/B000OPDFLM
Since they are optically isolated they can be connected anywhere in
the circuit without creating unwanted current paths through their
cabling, a major concern with grounded instruments like scopes. You
can combine their separate datalog files into a spreadsheet by
aligning the timestamps.

A laptop makes it easy to set up in the best place to run the test.
For me that's in the laundry room where I have running water to deal
with battery acid spills. The laptop itself can be the representative
load on the battery and its own internal battery will keep it running
when the battery being tested drops out, so it doesn't lose the most
important data point. The time that happens, saved in the system
Event Log, may be all you need to know. Older, thicker laptops with
CardBus or ExpressCard slots for port adapters to read multiple meters
are cheap.


My pure sine inverter reports status over a hand-wired non-standard
cable to a monitoring program I wrote but I haven't found much use for
the results. This is more valuable:
https://www.amazon.com/bayite-6-5-10...yite+100v+100a
If that link doesn't work it's a Bayite PZEM-051.

This VAC-1030A could be great if they fixed a few minor bugs and wrote
a decent manual. It's good enough already.
http://www.ebay.com/itm/VAC1030A-The...-/262562495499
I haven't tried the 100A model, VAC-1100A, because I normally recharge
at a current too low for it to measure accurately, though the
VAC-1030A isn't much better.

If I had a solar system, I'd have an arduino or some such
monitoring it at all times.

Monitoring my solar system showed that clouds pass randomly and I
still need a backup generator since I can't depend on a consistently
adequate solar output, especially in the kind of weather when I'd need
it most. I occasionally check the output and wiring drops on bright,
clear days. A cheap HF DVM gives the short circuit current.and an RC
wattmeter and variable resistor can find the maximum power point.
https://www.amazon.com/Tenergy-Preci.../dp/B017YCTRKK
That's just an example, not the discontinued meter I own. It shows
that the power doesn't fall off much on either side of the maximum,
meaning there's little benefit from an MPPT controller on a small
system.

-jsw

"mike" wrote in message
news
On 5/22/2017 9:34 AM, Jim Wilkins wrote:
...
A computer controlled dual-output power supply is a useful tool.
Use one output to charge the battery and read back the voltage.
Use the other output to drive a voltage to current converter for the
load.
Makes it very easy to control and log and graph and...


What happens to the expensive power supply if the AC power fails while
the battery is connected, or you accidentally connect the battery
backwards???
http://www.keysight.com/main/editori...03725:epsg:faq
"Active loads that create a sinking current should not be connected to
a power supply."

I've been charging batteries through series diodes, using this meter
to monitor the voltage beyond the diode drop:
https://www.amazon.com/DROK-Digital-.../dp/B015R3PMFC
"With reverse polarity protection to avoid burning out"
A spare LM78xx from your junk collection can extend their supply
voltage rating above the input limit, an LM7824 increases it the
highest.

The one I tested the other night matched a 5-1/2 digit Fluke to 1 mV
at 10V in. Notice where it was made.

The output protection I've been adding to my homebrew battery charging
variable power supplies is a forward diode to block a meter-busting
surge back into the 0.2 Farad output cap and a reverse-biased diode to
ground that -should- pop the output fuse or breaker if a battery is
connected backwards. The problem with testing breakers is that they
have a maximum interrupting rating above which they may work only
once, and of course with fuses is that you know they -did- work and
hope the next one (from a different source?) is the same.
-jsw

On Mon, 22 May 2017 18:39:59 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Mon, 22 May 2017 08:34:11 -0400, "Jim Wilkins"
wrote:
...
Previously I was using a rewired Battery Isolator I bought from
Quicksilver Radio for $5 at a hamfest ...
....
Those I've seen only engage the relay to switch to the secondary
battery. Are you talking about when the secondary battery is
discharged/cutoff and the relay continuing to be engaged? I see
that
as a problem, too. Perhaps rig up a kickout relay to disengage when
the cutoff hits on the secondary?

This one remains powered by the main battery when it switches the load
to the second one, perhaps to avoid the glitch while the
break-before-make relay contact is moving. It drives the relay with an
SCR and won't release and revert to the main battery until the user
pushes a disconnect button, regardless of how high the main battery
may have recovered or been recharged. This means that connecting NO to
a charger won't make the relay turn off when the battery voltage
rises.

I cut and jumpered the traces to redefine COM as the battery instead
of the load, which is now NC. Originally COM was the load, NC the main
battery and NO the secondary one. As you said it would simply allow
the secondary battery to die, but retain whatever capacity the trip
point left in the main battery.

Maybe running the anchor light as long as possible is more important
than preserving a battery that sinks when the boat is hit?

That would do it.


I haven't seen that remaining for an hour or so at full discharge
would further harm a battery and want to record the voltage it
recovers to without any load as an indication of true remaining
capacity and a safety check that I haven't set the disconnect
voltage
too low and drained the battery too far.

Yeah, that's a fly in the ointment of capacity measurement. Are you
saying "full discharge to cutoff point" there?

(Which you didn't answer.)


Here's the problem:
http://batteryuniversity.com/learn/a...tate_of_charge
"To get accurate readings, the battery needs to rest in the open
circuit state for at least four hours..."

The AGM I discharged at a little less than the 20 hour rate (0.5A)
tripped at 10.0V (twice) and then recovered to 12.15V, which is over
40% State-of-Charge on that chart.

And you thought the tripping was from the internal resistances, didn't
you? But the deeper the DOD, the shorter the battery life. (Loved
the Hot Tip on the Fridge and Solar site. Batteries love to be
charged but don't much like being discharged, etc.) Speaking of
which, what's the difference (other that price) between the standard
Ford style starter relay @ $12.99 delivered and the $80 Enerdrive VSR
super-duper battery disconnect switch? As I look at it again, I see
that it has voltage-sensitive engagement. ($0.37 worth of old 7400
series chips?)


The point of knowing the full capacity is to find out why I'm not
getting it, and see if anything I can do makes an improvement. I can't
fix bad interconnects but a discharge - charge - equalize cycle
reforms the active material. Only measurements will show how well
equalizing and desulfating work.

IIRC, I recently read that EQ can be good, but frequent EQ shortens
battery life.


I know I can make them last much
longer than usual, but is it worth the effort?

Good question. Perhaps with a more expensive battery, it would be, or
in a top-down situ where the grid is and stays out. I rather doubt it
with UPS batteries otherwise, though. Q: are the internal plates and
connections in the larger glass mat batteries the same as the smaller
AGM UPS batteries? I do know that the larger, PV-rated LA batteries
are more up to the task, and they're really heavy (massive lead
plates) and pricy.

It seems like this would have been done and written about by many a
battery manufacturer by now, or by their ad people. "Our batteries
and chargers are better because..." But I grok the "need to know"
function, too. I believe I'll be getting a lot of experience and
experimentation in the next decade, too, playing with solar.

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

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

...
I haven't seen that remaining for an hour or so at full discharge
would further harm a battery and want to record the voltage it
recovers to without any load as an indication of true remaining
capacity and a safety check that I haven't set the disconnect
voltage
too low and drained the battery too far.

Yeah, that's a fly in the ointment of capacity measurement. Are
you
saying "full discharge to cutoff point" there?

(Which you didn't answer.)


Here's the problem:
http://batteryuniversity.com/learn/a...tate_of_charge
"To get accurate readings, the battery needs to rest in the open
circuit state for at least four hours..."

The AGM I discharged at a little less than the 20 hour rate (0.5A)
tripped at 10.0V (twice) and then recovered to 12.15V, which is over
40% State-of-Charge on that chart.

Thus taking the battery down to 10V cutoff at the 20 hour rate wasn't
a full discharge, so I couldn't answer. There was still capacity left
that was unavailable for some reason, perhaps one higher resistance
cell that I might be able to bring back by slow equalizing. 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.

And you thought the tripping was from the internal resistances,
didn't
you? But the deeper the DOD, the shorter the battery life. (Loved
the Hot Tip on the Fridge and Solar site. Batteries love to be
charged but don't much like being discharged, etc.) Speaking of
which, what's the difference (other that price) between the standard
Ford style starter relay @ $12.99 delivered and the $80 Enerdrive
VSR
super-duper battery disconnect switch? As I look at it again, I see
that it has voltage-sensitive engagement. ($0.37 worth of old 7400
series chips?)

I had bought some LM324s and a relay to build one before I found the
Battery Isolator for $5. It's a hand-drawn circuit board in a Radio
Shack grey aluminum box, like the stuff I built as a kid, though it
seems to work well enough.


IIRC, I recently read that EQ can be good, but frequent EQ shortens
battery life.

Since I don't cycle my batteries daily I can afford to experiment with
slow charging from the solar panels at a few percent of the Amp-Hour
rating current. Rather than adding a current limiter which would cut
into the already minimal voltage overhead of solar panels, I've been
charging with simple, rugged LM317 and LM350 regulators with meters
and bumping the voltage up a little when I walk by and notice the
current has dropped. Before long the battery charges high enough that
an AGM draws only C/100 current at 15V and a flooded battery at around
14.0V, though they all are different. The current lost to electrolysis
seems to decrease, as shown by the battery drawing little more current
above 14V than at 13.6V.

I built a homebrew power supply whose current limiter adjusts from
1mA to 0.4A. I use it to restore old electrolytic capacitors at about
5mA and to desulfate free batteries that need to be hit with over 16V
to accept any current. For them the current needs a limiter to avoid
pegging the ammeter as they recover. I've been using one such free
"dead" battery in my tractor for two years.

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.

It may be the sort of gizmo that only the inventor can make work, too
troublesome to be commercially valuable. I've come up with several
ideas that work fine for me but no one else.

I know I can make them last much
longer than usual, but is it worth the effort?

Good question. Perhaps with a more expensive battery, it would be,
or
in a top-down situ where the grid is and stays out. I rather doubt
it
with UPS batteries otherwise, though. Q: are the internal plates
and
connections in the larger glass mat batteries the same as the
smaller
AGM UPS batteries? I do know that the larger, PV-rated LA batteries
are more up to the task, and they're really heavy (massive lead
plates) and pricy.

AFAIK flooded batteries can be nursed to live longer than
maintenance-proof ones, so I lack the experience to answer that. I
don't own batteries larger than I can carry down the stairs and
outdoors to let them gas freely when I equalize them.

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.

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.

It seems like this would have been done and written about by many a
battery manufacturer by now, or by their ad people. "Our batteries
and chargers are better because..." But I grok the "need to know"
function, too. I believe I'll be getting a lot of experience and
experimentation in the next decade, too, playing with solar.

Neon John posted a good reference to actual experience maintaining
backup batteries. I haven't found much else that gives hard technical
details instead of wishful copywriter promises. I did some work once
on 48V telco battery banks, otherwise my industrial experience is
mainly with Lithiums which are still overly expensive.

-jsw

On 5/24/2017 6:49 AM, Jim Wilkins wrote:


Since I don't cycle my batteries daily I can afford to experiment with
slow charging from the solar panels at a few percent of the Amp-Hour
rating current. Rather than adding a current limiter which would cut
into the already minimal voltage overhead of solar panels,

There are some nifty hall-effect sensors with almost zero drop.
Used one in a solar/wind system with a shunt regulator.
Wind generators don't like being unloaded by a series regulator.

I've been
charging with simple, rugged LM317 and LM350 regulators with meters
and bumping the voltage up a little when I walk by and notice the
current has dropped. Before long the battery charges high enough that
an AGM draws only C/100 current at 15V and a flooded battery at around
14.0V, though they all are different. The current lost to electrolysis
seems to decrease, as shown by the battery drawing little more current
above 14V than at 13.6V.

I built a homebrew power supply whose current limiter adjusts from
1mA to 0.4A. I use it to restore old electrolytic capacitors at about
5mA and to desulfate free batteries that need to be hit with over 16V
to accept any current. For them the current needs a limiter to avoid
pegging the ammeter as they recover. I've been using one such free
"dead" battery in my tractor for two years.

I'd like to hear more about your desulfation successes.
High voltage didn't help. Other crazy ideas I'd read about, like
AC at various frequencies to 'ring' the plates
and shake off sulfation, etc. Got absolutely nowhere.

"mike" wrote in message
news
On 5/24/2017 6:49 AM, Jim Wilkins wrote:


Since I don't cycle my batteries daily I can afford to experiment
with
slow charging from the solar panels at a few percent of the
Amp-Hour
rating current. Rather than adding a current limiter which would
cut
into the already minimal voltage overhead of solar panels,

There are some nifty hall-effect sensors with almost zero drop.
Used one in a solar/wind system with a shunt regulator.
Wind generators don't like being unloaded by a series regulator.

http://www.ebay.com/itm/Bayite-DC-5-...-/361553795712

How stable is the zero reading? This is the best DC Hall effect
ammeter I've seen and its zero drifts by several mA per minute if held
still. When moved the Earth's magnetic field throws it way off.
https://www.eevblog.com/forum/testge...-uni-t-ut210e/

I built a homebrew power supply whose current limiter adjusts from
1mA to 0.4A. I use it to restore old electrolytic capacitors at
about
5mA and to desulfate free batteries that need to be hit with over
16V
to accept any current. For them the current needs a limiter to
avoid
pegging the ammeter as they recover. I've been using one such free
"dead" battery in my tractor for two years.

I'd like to hear more about your desulfation successes.
High voltage didn't help. Other crazy ideas I'd read about, like
AC at various frequencies to 'ring' the plates
and shake off sulfation, etc. Got absolutely nowhere.

http://batteryuniversity.com/learn/a..._to_prevent_it
I've fixed several "dead" U1R lawn tractor batteries and used them for
several years. The symptom was not accepting more than a few milliAmps
from a commercial charger, although the resting voltage seemed OK. The
fix was using the variable power supply to force 16V to 17V which
caused the current to very slowly increase and then the required
charging voltage to drop, an unstable condition that requires current
limiting, such as with a low end lab-type supply like these if you
can't rig up your own.
https://www.amazon.com/Dr-meter-PS-3.../dp/B00O8DJ8QC

After the battery had accepted enough charge to raise the electrolyte
level I checked specific gravity and found one or two low cells.
Charging at a current that didn't make the others bubble excessively,
around 0.5A, eventually brought up the low cells. The resurrected U1R
in the tractor now can put 150A into my HF carbon pile load tester.

I've read that salvaging batteries this way can take up to a week. I
saw progress with salvageable flooded batteries in a few hours but
haven't had much luck with AGMs.

The neighbors who give me these batteries know I can fix them, and
that they will need frequent attention afterwards. I have to top up
the charge at least monthly or their internal resistance will rise
again.

I don't know if the cause is literally lead sulfate recrystallization
or not but it's a handy suspect to blame. There's a theory that it's a
thin oxide barrier between the grid and the active material.
Whatever the cause, the effect is a very high internal resistance.
Automatic chargers see the voltage rise as though the battery was
fully charged and shut off. Some people have reported success using a
Harbor Freight manual charger on a Variac as the variable supply.
-jsw

On Mon, 22 May 2017 12:34:09 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
news
On Sun, 21 May 2017 19:49:32 -0400, "Jim Wilkins"
wrote:

..................
http://www.trojanbattery.com/pdf/Tro...UsersGuide.pdf
Diagram 4 gives 1-3% for flooded, Diagram 5 gives 0.5% for AGM.

I've downloaded both guides you've mentioned in the past several
days
and will have to compare them. Each one will have tidbits of info
the
other doesn't. That's the true benefit of research: gleaning
tidbits.


As mentioned, the current rises in older batteries and is an
indicator
of declining condition.

That sounds like something I should pay attention to.

I suspect it means that the self-discharge rate has increased and they
may need more frequent topping off. I don't know how it relates to
remaining capacity.

Ahh, OK.


The second one matches other ammeters to 1 or 2 digits and I use
both
in series for discharge loads up to 10A. Together they each make
up
for the deficiencies of the other. The 12V,12Ah battery is
discharging
on them at 0.5A.

I forgot to ask what you meant by that. Are they drawing half an
amp
or showing that discharge rate?

I kept the current from the battery close to 0.5A by tweaking the
rheostat load. Surplus phone chargers power the meters and the relay
independently from the battery, since I won't be wasting my backup by
running these discharge tests into a dummy load during a power outage.

Some of my homebrew test equipment runs on AC power for better
accuracy, some on DC from the battery being tested or the solar panels
so it will still show demand or charging rate during a power outage.
The load current varies too much for accurate measurement and battery
remaining life prediction, but all I really need to know is if the
batteries can run the fridge overnight.

OK, so your -fridge- demands 0.5A? titter It's hard for me to
conceptualize a half amp draw at 12v, as few things operate at that
level.


The box whose components I tested this morning will have a switch for
internal or external power. The meters have to be on external power to
measure single 18650 Lithiums to their discharge endpoint which is
below the minimum supply voltage..

I'm fairly fond of 18650s, having used them in the LED flashlights for
awhile now. I love that Lithiums don't self-destruct, and don't suck
their own juices from themselves while they sit on a shelf. Nicads
and LAs have always bothered me with that nasty characteristic.


The two of these I bought match the Fluke 8800A to 1mV. YMMV.
https://www.amazon.com/DROK-Digital-.../dp/B01BXZNK0C

Amazing, but good news.


Did I ever ask you why you didn't use a real battery for that? g
(real being 12v 35-275Ah) I set one up for use with the 45w HF
trio
of panels and was able to power a 14" electric chainsaw with the
2kW
modified sine wave inverter, also from HF. It would have taken
days
to recharge it (or more panels if needed for continued use.)

I do have "real" batteries that will run the fridge for about 20
hours. Once I'm satisfied with my discharge testing setup I'll get
to
them. For now I'm testing and risking smaller, older, less valuable
jumpstarter and UPS AGMs.

Smart.


These tests are too long to watch and if the
low voltage disconnect fails the battery could be drained flat
before
I notice.

That wouldn't be fun. How often do the disconnect programs (or
hardware/relays) fail?

How often do brakes fail?

Notalotta, but it's a bummer when they do.

Are you trying to (or not to) tell me about a box full of 18650s
you're putting together to run your fridge when the power's out?
Testing those with a 6w drain just might be the connection my mind
continues to search for with your bloody half amp thing.

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

"Larry Jaques" wrote in message
...
On Mon, 22 May 2017 12:34:09 -0400, "Jim Wilkins"
wrote:

.....
I forgot to ask what you meant by that. Are they drawing half an
amp
or showing that discharge rate?

I kept the current from the battery close to 0.5A by tweaking the
rheostat load. Surplus phone chargers power the meters and the relay
independently from the battery, since I won't be wasting my backup
by
running these discharge tests into a dummy load during a power
outage.

Some of my homebrew test equipment runs on AC power for better
accuracy, some on DC from the battery being tested or the solar
panels
so it will still show demand or charging rate during a power outage.
The load current varies too much for accurate measurement and
battery
remaining life prediction, but all I really need to know is if the
batteries can run the fridge overnight.

OK, so your -fridge- demands 0.5A? titter It's hard for me to
conceptualize a half amp draw at 12v, as few things operate at that
level.

Maybe I should have repeated that I was discussing a different battery
closer to the mention of the fridge? I post all this to practice
clear, concise technical writing and then try to determine why it's so
often misinterpreted.

The fridge takes 120W initially, slowly dropping to 80W, as measured
with a Kill-A-Watt on wall AC. When the power goes out it runs from an
APC1400 SmartUPS pure sine inverter with two external 12V Group 31
batteries. Discharge tests on them could end in the middle of the
night and let my fridge warm up, so I bought equipment to automate the
capacity measurement with safe loads.

I'm checking out that equipment on less valuable batteries that don't
take nearly as long to discharge. I've been posting a summary of
significant observations, not a daily diary of my experiments, so I
haven't always clearly indicated which battery or test load they came
from. The 0.5A test was to measure the C/20 capacity of a smaller AGM
battery from a 350W UPS.

...
Are you trying to (or not to) tell me about a box full of 18650s
you're putting together to run your fridge when the power's out?
Testing those with a 6w drain just might be the connection my mind
continues to search for with your bloody half amp thing.

I found a source of tabbed Li-ion 18650s for $2 each and hope to
restore old laptop batteries etc with them. They appear to have been
in storage long enough that some dropped below their low voltage
safety disconnect, but still accept a charge applied directly to the
tabs.

-jsw

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 haven't seen that remaining for an hour or so at full discharge
would further harm a battery and want to record the voltage it
recovers to without any load as an indication of true remaining
capacity and a safety check that I haven't set the disconnect
voltage
too low and drained the battery too far.

Yeah, that's a fly in the ointment of capacity measurement. Are
you
saying "full discharge to cutoff point" there?

(Which you didn't answer.)


Here's the problem:
http://batteryuniversity.com/learn/a...tate_of_charge
"To get accurate readings, the battery needs to rest in the open
circuit state for at least four hours..."

The AGM I discharged at a little less than the 20 hour rate (0.5A)
tripped at 10.0V (twice) and then recovered to 12.15V, which is over
40% State-of-Charge on that chart.

Thus taking the battery down to 10V cutoff at the 20 hour rate wasn't
a full discharge, so I couldn't answer. There was still capacity left
that was unavailable for some reason, perhaps one higher resistance
cell that I might be able to bring back by slow equalizing.

Hmm.


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?


And you thought the tripping was from the internal resistances,
didn't
you? But the deeper the DOD, the shorter the battery life. (Loved
the Hot Tip on the Fridge and Solar site. Batteries love to be
charged but don't much like being discharged, etc.) Speaking of
which, what's the difference (other that price) between the standard
Ford style starter relay @ $12.99 delivered and the $80 Enerdrive
VSR
super-duper battery disconnect switch? As I look at it again, I see
that it has voltage-sensitive engagement. ($0.37 worth of old 7400
series chips?)

I had bought some LM324s and a relay to build one before I found the
Battery Isolator for $5. It's a hand-drawn circuit board in a Radio
Shack grey aluminum box, like the stuff I built as a kid, though it
seems to work well enough.

I've seen soldered IC, resistor, capacitor forever encased in clear
RTV which, while not purty, was fully functional.


IIRC, I recently read that EQ can be good, but frequent EQ shortens
battery life.

Since I don't cycle my batteries daily I can afford to experiment with
slow charging from the solar panels at a few percent of the Amp-Hour
rating current. Rather than adding a current limiter which would cut
into the already minimal voltage overhead of solar panels, I've been
charging with simple, rugged LM317 and LM350 regulators with meters
and bumping the voltage up a little when I walk by and notice the
current has dropped. Before long the battery charges high enough that
an AGM draws only C/100 current at 15V and a flooded battery at around
14.0V, though they all are different. The current lost to electrolysis
seems to decrease, as shown by the battery drawing little more current
above 14V than at 13.6V.

OK, I think I now have the full picture.


I built a homebrew power supply whose current limiter adjusts from
1mA to 0.4A. I use it to restore old electrolytic capacitors at about
5mA and to desulfate free batteries that need to be hit with over 16V
to accept any current. For them the current needs a limiter to avoid
pegging the ammeter as they recover. I've been using one such free
"dead" battery in my tractor for two years.

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'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.


It may be the sort of gizmo that only the inventor can make work, too
troublesome to be commercially valuable. I've come up with several
ideas that work fine for me but no one else.

For most people, plug-n-play is the only way. For Makers like those
of us on RCM, fiddlin' is the only way.


I know I can make them last much
longer than usual, but is it worth the effort?

Good question. Perhaps with a more expensive battery, it would be,
or
in a top-down situ where the grid is and stays out. I rather doubt
it
with UPS batteries otherwise, though. Q: are the internal plates
and
connections in the larger glass mat batteries the same as the
smaller
AGM UPS batteries? I do know that the larger, PV-rated LA batteries
are more up to the task, and they're really heavy (massive lead
plates) and pricy.

AFAIK flooded batteries can be nursed to live longer than
maintenance-proof ones, so I lack the experience to answer that. I
don't own batteries larger than I can carry down the stairs and
outdoors to let them gas freely when I equalize them.

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.


It seems like this would have been done and written about by many a
battery manufacturer by now, or by their ad people. "Our batteries
and chargers are better because..." But I grok the "need to know"
function, too. I believe I'll be getting a lot of experience and
experimentation in the next decade, too, playing with solar.

Neon John posted a good reference to actual experience maintaining
backup batteries. I haven't found much else that gives hard technical
details instead of wishful copywriter promises. I did some work once
on 48V telco battery banks, otherwise my industrial experience is
mainly with Lithiums which are still overly expensive.

New Atlas had an article recently on doubling the density of lithiums.
I hope Tesla Gigafactory takes advantage of it. That should drop the
price considerably.

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

On Mon, 22 May 2017 20:53:17 -0400, "Jim Wilkins"
wrote:

"Jim Wilkins" wrote in message
news
http://batteryuniversity.com/learn/a...nal_resistance
The two-tier DC load method is how the engineer had me test electric
vehicle Lithiums,

Interesting. It looks like I'm going to have to take their "course"
to get more up to speed. Until now, I had never heard how CCAs were
measured.


using a programmable electronic load and a much
better DC current probe than I'll probably ever own personally.

Indeed. Some equipment cost is measured by X years of debt and probe
valued at X months of wages. =:-0

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

On Thu, 25 May 2017 07:53:31 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Mon, 22 May 2017 12:34:09 -0400, "Jim Wilkins"
wrote:

.....
I forgot to ask what you meant by that. Are they drawing half an
amp
or showing that discharge rate?

I kept the current from the battery close to 0.5A by tweaking the
rheostat load. Surplus phone chargers power the meters and the relay
independently from the battery, since I won't be wasting my backup
by
running these discharge tests into a dummy load during a power
outage.

Some of my homebrew test equipment runs on AC power for better
accuracy, some on DC from the battery being tested or the solar
panels
so it will still show demand or charging rate during a power outage.
The load current varies too much for accurate measurement and
battery
remaining life prediction, but all I really need to know is if the
batteries can run the fridge overnight.

OK, so your -fridge- demands 0.5A? titter It's hard for me to
conceptualize a half amp draw at 12v, as few things operate at that
level.

Maybe I should have repeated that I was discussing a different battery
closer to the mention of the fridge? I post all this to practice
clear, concise technical writing and then try to determine why it's so
often misinterpreted.

Data is far easier to get scattered on Usenet, where we potentially
zip through hundreds of items with dozens of topics daily. But, yeah.


The fridge takes 120W initially, slowly dropping to 80W, as measured
with a Kill-A-Watt on wall AC. When the power goes out it runs from an
APC1400 SmartUPS pure sine inverter with two external 12V Group 31
batteries. Discharge tests on them could end in the middle of the
night and let my fridge warm up, so I bought equipment to automate the
capacity measurement with safe loads.

My 2002 Frigidaire 18cf fridge uses only 135w with the compressor
running. I didn't track it while running, so mine may have tapered
off once the system normalized. That figure really surprised me, it
was so low. The '80s model before it took a lot more power to run.
Progress is good.


I'm checking out that equipment on less valuable batteries that don't
take nearly as long to discharge. I've been posting a summary of
significant observations, not a daily diary of my experiments, so I
haven't always clearly indicated which battery or test load they came
from. The 0.5A test was to measure the C/20 capacity of a smaller AGM
battery from a 350W UPS.

Yes, I finally came to that realization yesterday after having some
fun with you. So solly.


...
Are you trying to (or not to) tell me about a box full of 18650s
you're putting together to run your fridge when the power's out?
Testing those with a 6w drain just might be the connection my mind
continues to search for with your bloody half amp thing.

I found a source of tabbed Li-ion 18650s for $2 each and hope to
restore old laptop batteries etc with them. They appear to have been
in storage long enough that some dropped below their low voltage
safety disconnect, but still accept a charge applied directly to the
tabs.

Z-tabbed for spotwelding, or other? I'm not sure if the cheapies I
bought have the protection cell, so maybe you're talking about
bypassing it on your genuine cells. Maybe I'll rip one apart and see
if it's done properly. (Judging by Youtube vids, they don't have the
protection cell.)

I found a source of (supposedly) new 18650s on eBay for a buck apiece
with wild claims of up to 6000ma capacity. I figure 1,500 to be the
norm, and they're worth a buck. AC and DC chargers go for a buck a
pop now and then, too, so I stock up. Bright LED (XLM-T6 and Q5)
flashlights and headlamps go for $2-5 each so I got sets for the whole
family as stocking stuffers one Christmas.

The 18650/T6 combo lasts a couple hours on high, and my normal use is
under 3 minutes (forgotten mail, raccoon in tree) so I'm happy. The
zoomable waterproof lights are great, but I seldom use medium or low
beam, or the flasher or SOS modes. http://tinyurl.com/l8xgsf7
The zoom function works well on the bike, but I'm not crazy enough to
ride at night. It allows you to set your own beam width.

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

"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
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.

...
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.

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.

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.

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.

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.

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.



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
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.

...
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.

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.

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.

-jsw

"Larry Jaques" wrote in message
...
On Thu, 25 May 2017 07:53:31 -0400, "Jim Wilkins"
wrote:


Yes, I finally came to that realization yesterday after having some
fun with you. So solly.

Don't be. I've intentionally chosen proofreaders who would take
everything the wrong way when I was ambiguous. That's why I wrote the
"press any key" routine that faked a crash on Alt or Shift.

-jsw

"Larry Jaques" wrote in message
...
On Mon, 22 May 2017 20:53:17 -0400, "Jim Wilkins"
wrote:

"Jim Wilkins" wrote in message
news
http://batteryuniversity.com/learn/a...nal_resistance
The two-tier DC load method is how the engineer had me test electric
vehicle Lithiums,

Interesting. It looks like I'm going to have to take their "course"
to get more up to speed. Until now, I had never heard how CCAs were
measured.
http://batteryuniversity.com/learn/a...d_cranking_amp
The HF carbon pile performs the test as they specify, with a 15 sec
timer to warn you to turn the current down before it overheats. So far
it seems to be a good and relatively inexpensive tool to measure the
margin your battery has over the starting current your vehicle
requires.




using a programmable electronic load and a much
better DC current probe than I'll probably ever own personally.

Indeed. Some equipment cost is measured by X years of debt and
probe
valued at X months of wages. =:-0

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

"Jim Wilkins" wrote in message
news
"Larry Jaques" wrote in message
...

http://batteryuniversity.com/learn/a...nal_resistance

Interesting. It looks like I'm going to have to take their
"course"
to get more up to speed.

Here is a good, simple overview of battery charging:
http://www.iotaengineering.com/pplib..._Batteries.pdf

I use simple dumb chargers for the high current bulk phase and
smaller, more efficient and better controlled ones for the final ones.
It costs nothing to leave a battery on a solar powered charger. The
big chargers draw idle power, transformer magnetizing current, that
may be more than goes into the battery. I've added an input tap after
the rectifier to let a charger operate on solar if available or grid
power if not.

"The charging parameters
discussed here are applicable to ?ooded lead acid batteries. Be aware
that
some available smart chargers may
not be suitable for other applications."

However the makers post their products' parameters, which aren't hard
to meet with a voltage-adjustable power supply with meters. Some of my
AGMs have the charging conditions printed on the cases.
-jsw

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

"Larry Jaques" wrote in message
news
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
m...
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.

They had to be assembled somehow.

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.

Yep, works fine as long as I keep the voltage from spiking above the
safe input limit when the current is interrupted. The welder
transformer has that nasty habit and so do poorly regulated
generators. Testing this stuff drove me to buy the (older) HF inverter
generator, which holds a very steady 120V from no to full load. The
Coleman I had been using need to be set close to 140V at no load to be
able to supply barely 100V at full load. The APC rejected its output
and stayed on battery until I found how to reduce the line quality
sensitivity.

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.

The APC1400 needs 24V, originally from two internal 12V 18Ah AGMs in
series. Their heavy cables run to a rear panel Anderson plug, in a Y
shape with the battery on one leg, the inverter on another and a
safety disconnect shorting plug on the third, normally at the rear
panel. Moving the short to the internal battery position makes the
rear panel plug the input.

I ran fused twisted pairs from each battery to a voltmeter and switch
panel under my Harbor Freight solar controller. They connect to a DPDT
center off selector switch that can tie the HF controller to either
battery. Both wires in the pairs are fused to protect against any
switch failure, since the batteries may still be connected in series.

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 lived in the center of the track of Hurricane Carol. The eye passed
right over us and was quite spectacular, bright sun lighting an
enormous dark ring wall.
https://en.wikipedia.org/wiki/Hurricane_Carol
Afterwards my father found gasoline at a station that had rigged a
Jeep to run one pump and drove around to assess the damage, as far as
we could since fallen trees blocked many roads. Back then few people
had the chainsaws or generator so widely available now but we managed
to recover without too much trouble.

Do you belong to a church or club with an experienced leadership
structure, that knows members' abilities and how to organize events?

-jsw

On Fri, 26 May 2017 11:14:43 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Thu, 25 May 2017 07:53:31 -0400, "Jim Wilkins"
wrote:


Yes, I finally came to that realization yesterday after having some
fun with you. So solly.

Don't be. I've intentionally chosen proofreaders who would take
everything the wrong way when I was ambiguous. That's why I wrote the
"press any key" routine that faked a crash on Alt or Shift.

snort Have you seen these? http://tinyurl.com/yb93b6f8

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

"Larry Jaques" wrote in message
...
On Fri, 26 May 2017 11:14:43 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
. ..
On Thu, 25 May 2017 07:53:31 -0400, "Jim Wilkins"
wrote:


Yes, I finally came to that realization yesterday after having
some
fun with you. So solly.

Don't be. I've intentionally chosen proofreaders who would take
everything the wrong way when I was ambiguous. That's why I wrote
the
"press any key" routine that faked a crash on Alt or Shift.

snort Have you seen these? http://tinyurl.com/yb93b6f8

Cute, but just a one-time sight gag unless you can write a routine
that detects and responds to them.

I've used Dial-A-Prayer for that sort of prank. It's an ominous
warning when -they- call -you-, right? (transfer the call)

On Sun, 28 May 2017 07:33:45 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
.. .
On Fri, 26 May 2017 11:14:43 -0400, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
...
On Thu, 25 May 2017 07:53:31 -0400, "Jim Wilkins"
wrote:


Yes, I finally came to that realization yesterday after having
some
fun with you. So solly.

Don't be. I've intentionally chosen proofreaders who would take
everything the wrong way when I was ambiguous. That's why I wrote
the
"press any key" routine that faked a crash on Alt or Shift.

snort Have you seen these? http://tinyurl.com/yb93b6f8

Cute, but just a one-time sight gag unless you can write a routine
that detects and responds to them.

Yeah, it's only good for people walking by your keyboard and finding
the infamous ANY key. I wonder how many they sell at $26 a pop!


I've used Dial-A-Prayer for that sort of prank. It's an ominous
warning when -they- call -you-, right? (transfer the call)

Eek! (running away) I had a nice church lady spittin' nails a while
back when she read the sign on my front window. I didn't have to
answer the door, and I could hear her through the window and see her
through the translucent white curtain. She wanted to spew religion at
me and that sign made her show her true colors. I'll bet the man with
her never went out with her again. He left with a smile on his face,
following behind her. http://tinyurl.com/hyefhtu


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