Today's Message Index:
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1. 05:54 AM - Re: Charger needed to revive 18 aH Lead Acid Batteries (Robert L. Nuckolls, III)
2. 06:20 AM - Re: 1948 Cartoon (Robert L. Nuckolls, III)
3. 10:18 AM - Re: Charger needed to revive 18 aH Lead Acid Batteries (rparigoris)
4. 10:21 AM - "Pulled Low to Ground"........(Huh?) (stearman456)
5. 10:45 AM - Re: "Pulled Low to Ground"........(Huh?) (Bill Watson)
6. 11:19 AM - Re: "Pulled Low to Ground"........(Huh?) (Bill Watson)
7. 12:45 PM - Re: "Pulled Low to Ground"........(Huh?) (Robert L. Nuckolls, III)
8. 01:23 PM - Re: "Pulled Low to Ground"........(Huh?) (stearman456)
9. 01:32 PM - Re: Re: Charger needed to revive 18 aH Lead Acid Batteries (Robert L. Nuckolls, III)
10. 02:06 PM - Re: Re: Charger needed to revive 18 aH Lead Acid Batteries (Robert L. Nuckolls, III)
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Subject: | Re: Charger needed to revive 18 aH Lead Acid Batteries |
At 06:22 PM 8/29/2012, you wrote:
<rparigor@suffolk.lib.ny.us>
Hi Group
I have a task to try and revive some 18 aH 12 volt sealed AGM
batteries that weigh in at ~ 14.5 pounds.
The charger that was being used on them begins at a 3.5aH charger,
then slows down a bit and peaks ~ 14.2/3 then goes to 13.7 float.
After a while, I don't know if from letting discharge too much or for
too long, or the 3.5 aH is a bit too fast, but what happens is the
batteries although they peak and go to float, they really don't take
too much of a charge and have a very low capacity.
How long does the charger stay in a top-off mode? 3.5
amps charge is okay. But the absorption charge should
sustain at 14.7 or so until the charge acceptance current
of the battery is 100 mA or less.
http://tinyurl.com/9s7kpww
I have a 900mA Yuasa motorcycle charger, that does a little better.
Now what I did find works really well, is using the fool cheapest of
cheap battery chargers I gave away with the 9aH batteries I sold on
AeroElectric.
Do you have a way to measure and plot the performance
of your charger. Also a way to measure real capacity
as a result of that charging protocol? One of these
West Mountain Radio analyzers can be used to both plot
charger performance -AND- confirm the battery's acceptance
of charge.
That charger is nothing more than a 500mA transformer that supplies a
constant 500mA current, then the circuit just looks for 15.4/5 and
turns off. Now mind you it can take not hours, but days to reach that
magic 15.4/5 number, and some batteries can not be revived, but most
can. Then I found that if I take two of these batteries and parallel
them and let the poor 500mA charger reach 15.4/5, it gets about as
good as it gets so far.
Yes, the higher trip point is well into the range
recommended for absorption charging . . . perhaps
a bit high but certainly high enough.
I think that the longer elevated voltage is perhaps desulfating??
Don't know if it's a sulfation problem at all,
just a quirk of the chemistry. Those two batteries
I bought from you have been subjected to a couple
of charge/discharge cycles using just a Battery
Tender and they seem to be taking on a full load
of watt-seconds.
Just for grins, I'll do a cap-check on one and then
do a manual, constant current charge that guarantees
sufficient dwell at absorption voltages and repeat the
cap-check.
There's a number of exemplar smart-charger profiles at:
http://tinyurl.com/9t6t8x8
in particular, take a look at this curve plotted on
a Schumacher 1562A
http://tinyurl.com/945zdog
it seems to be doing the right things in accordance
with contemporary wisdom
The Battery Tender Jr has the right moves too,
but not as defined. That's what I use to charge
and maintain a stack of test batteries here in
my shop.
Battery Minders behaved like this when I
tested them
http://tinyurl.com/9paguuy
Little or no absorption dwell, very low end
of charge trip point. I used to have a couple
but after doing these tests, I relegated them
to maintaining a fully charged battery only.
Gave them away to family members for keep batteries
in garden tractors and seldom used vehicles topped
off . . . but cautioned against expectations for
getting the battery up to 100%. It would probably
pump it up to a value that would start the engine.
Once the lawn was mowed, the machine's normal recharging
protocols would probably top off the battery where
the Battery Minder would be useful for maintaining
that condition.
I have a constant current 2 aH charger, and if I let it go much over
14.4 the batteries make a minor bubbling noise that I don't like too
much and figure if I let it go it will begin venting? I let it go 2
hours but the 500mA charge brought back more capacity.
Sorry for the long winded explain, what I need:
I need a consistent source for a fairly inexpensive charger that can
help revive these batteries.
I looked at Walmart, they have a 1.5 amp charger that peaks too low.
Is this the 1562 or it's offspring? I'm surprised
that it wouldn't behave much as the version I
tested some years ago. Schumacher is the BigDaddy
of battery charging tools. If anyone should know
how to do it right, it should be them.
I'll do a looksee to find out if the Battery Tender
falls short of top-off when used as a stand-alone
charger-maintainer.
I thought the short answer to your question would
be to pick up a Schumacher 1562 or current
replacement at Walmart. Do you have one of these
in hand? You could mail it to me and I can run some
plots on it.
Bob . . .
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Subject: | Re: 1948 Cartoon |
At 09:25 PM 8/29/2012, you wrote:
>A little thin-skinned are we, Joe?
Let us allow this thread to die. The posting was
inadvertent but in no instance does it warrant
a stirring of the pot of perception for personal
shortcomings. The truth, whether in physics or
honorable government lies in metrics derived
from repeatable experiments. To be sure, the
present experiment in Washington is demonstrating
many examples of how NOT to go about it.
We can fix experiments gone wrong on airplanes
here on the list. Experiments in Washington are
another matter. I'd hoped to spool up a forum for
those discussions but I'm still too busy with
plumbing and wires for the bathroom remod. In
mean time, let us not loose our grip on the mission
for this List . . . nor the decorum that promotes
accurate and useful exchange of knowledge.
Bob . . .
Message 3
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Subject: | Re: Charger needed to revive 18 aH Lead Acid Batteries |
Hi Bob
Thx. for the reply.
The chargers being used are Chargetek 3 stage chargers:
http://www.chargetek.com/resources/battery-charger-basics/
I didn't measure it, but the link says it turns off at between 1/100C and 1/50C,
so on a 17aH battery that is between 170 and 340mAs.
What is the amp draw that you need to drop below for the Schumacher 1562A to drop
out of absorption rate and go to float with a 17aH battery?
If it's 100mAs or less that may just be the ticket to success.
Is there a way to adjust this point to allow it to stay in absorb for a longer
time?
Thx.
Ron Parigoris
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=382141#382141
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Subject: | "Pulled Low to Ground"........(Huh?) |
In the Garmin SL-40 installation guide it says that both the transmit and intercomm
push-to-talks need to be "pulled low to ground". I'm asuming they just mean
the other wire of the switch goes to ground? I'm also asuming they mean radio/contact
ground, not airframe ground? Or am I missing something? Wish I
could post the schematic but I'm working from my Ipad and haven't figured out
how to do that yet!
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=382142#382142
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Subject: | Re: "Pulled Low to Ground"........(Huh?) |
Yes, "pull to ground" still doesn't sound right for this electronic
amateur but yes, that's what it means. It means the other wire of the
switch is connected to ground. Either one will work because they are
the same but... don't know.
Bill
On 8/30/2012 1:21 PM, stearman456 wrote:
>
> In the Garmin SL-40 installation guide it says that both the transmit and intercomm
push-to-talks need to be "pulled low to ground". I'm asuming they just
mean the other wire of the switch goes to ground? I'm also asuming they mean
radio/contact ground, not airframe ground? Or am I missing something? Wish
I could post the schematic but I'm working from my Ipad and haven't figured out
how to do that yet!
>
> Dan
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=382142#382142
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
>
>
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Subject: | Re: "Pulled Low to Ground"........(Huh?) |
On 8/30/2012 1:44 PM, Bill Watson wrote:
> <Mauledriver@nc.rr.com>
>
> Yes, "pull to ground" still doesn't sound right for this electronic
> amateur but yes, that's what it means. It means the other wire of
> the switch is connected to ground. Either one will work because they
> are the "same" but there may be a distinction
that makes the radio ground optimal... but I don't really know.
The way I understand it, I have all my avionic grounds run to a single
point and all my "pull to grounds" therefore are grounded to the same point.
>
> Bill
>
> On 8/30/2012 1:21 PM, stearman456 wrote:
>> <warbirds@shaw.ca>
>>
>> In the Garmin SL-40 installation guide it says that both the transmit
>> and intercomm push-to-talks need to be "pulled low to ground". I'm
>> asuming they just mean the other wire of the switch goes to ground?
>> I'm also asuming they mean radio/contact ground, not airframe
>> ground? Or am I missing something? Wish I could post the schematic
>> but I'm working from my Ipad and haven't figured out how to do that yet!
>>
>> Dan
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=382142#382142
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> -----
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>>
>>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
>
>
Message 7
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Subject: | Re: "Pulled Low to Ground"........(Huh?) |
At 12:21 PM 8/30/2012, you wrote:
>
>In the Garmin SL-40 installation guide it says that both the
>transmit and intercomm push-to-talks need to be "pulled low to
>ground". I'm asuming they just mean the other wire of the switch
>goes to ground? I'm also asuming they mean radio/contact ground,
>not airframe ground? Or am I missing something? Wish I could post
>the schematic but I'm working from my Ipad and haven't figured out
>how to do that yet!
This is an unfortunate scrambling of vernacular.
The function of a discrete CONTROL or SIGNAL path
is often described using these terms. For example,
the legacy control philosophy for closing the battery
contactor may be described as "pull to ground", "active
low", "pulled down", "low side switched" or simply
"switched ground". All of these phrases will bring
the same image to mind for someone who works across
several disciplines in electronics.
The other side of the coin describes the control
of something like your landing light where the
author might say "active hi", "pull up to bus",
"high side switched", etc.
Discrete levels in both the power and digital worlds
are not subject to interference from small noises
that might exist on the selected ground for a pull-to-
ground push-to-talk line. Many thousands of radios have produced
performance as advertised when their mic jacks were
simply grounded to airframe at the jack's mounting.
Of course, in our legacy 3-wire microphone architecture
this does put transmit audio at-risk for picking small
noises that may exist in currents that flow on the
airframe . . . hence a potential ground loop that
manifests in noise heard on transmitted audio while
those same noises had no effect on getting the transmitter
to become active with the PTT button.
I have often advised builders to "follow the manufacturer's
instructions' when it comes to dissecting the designer's
intent for installations. In the SL-40 wiring excerpt
Emacs!
We see that microphone and headset jack grounds are brought back
to the radio on their own wires . . . good practice. This
also means that the "pull down" on TxKey line by PTT buttons
on wired into these jacks will share that ground line wiht the
mic. This same drawing also shows "yolk mounted transmit buttons"
with an undefined ground. This is because the discrete control
line is not subject to the ground loop contamination and MAY
be grounded anywhere . . . which includes the option of taking
the wire all the way back to share a ground with the radio. Same
condition exists for the Intercom Selector Switch.
Bob . . .
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Subject: | Re: "Pulled Low to Ground"........(Huh?) |
Thanks, guys!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=382152#382152
Message 9
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Subject: | Re: Charger needed to revive 18 aH Lead Acid |
Batteries
At 12:16 PM 8/30/2012, you wrote:
<rparigor@suffolk.lib.ny.us>
Hi Bob
Thx. for the reply.
The chargers being used are Chargetek 3 stage chargers:
http://www.chargetek.com/resources/battery-charger-basics/
I didn't measure it, but the link says it turns off at between 1/100C
and 1/50C, so on a 17aH battery that is between 170 and 340mAs.
Hmmmm . . . okay. I seem to recall that Skip
Koss talked about recharge currents below 100
mA for terminating an absorption cycle on really
big batteries like the 30-50 a.h. aircraft batteries
we used at HBC. Kicking off that high seems a
bit 'light'.
What is the amp draw that you need to drop below for the Schumacher
1562A to drop out of absorption rate and go to float with a 17aH battery?
Have no idea. Never measured it. Don't know how
critical it is. Given that the Schumacher product
stayed in a absorption mode for a significant time
suggested that a righteous absorption charge was
being delivered. I don't have any 1562's around
to measure. I could put one of your Chargetek
machines on a DAS and find out where they are
calibrated.
If it's 100mAs or less that may just be the ticket to success.
Yes.
Just for grins, I took one of the 12a.h. batteries I
bought from you that has been on a Battery Tender
for the last several days (green light on, in maintenance
mode. Fooey, didn't read the float voltage first) and
hooked it to a 14.6v power supply. Charge current jumped
to 300mA and over the next 12 minutes it fell to 100mA.
Putting a crayon to the numbers suggests that the battery
is 12 a.h. x 12v x 3600 s/hr ~ 500,000 watt-seconds
at full charge. The little boost on the bench put in 200
mA average for 12 min for 0.2 x 14 x 720 ~ 2000 watt-seconds
or less than 0.5% of capacity. Hence I deduce (1) that the
Battery Tender did indeed return and support this battery
to 100% of rated capacity and (2) an end of absorption cycle
value of 100mA is not an unreasonable calibration point.
It would be interesting to plot an absorption cycle for
energy the battery takes on after recharge current drops
below 300mA . . . I'm guessing that it's probably less than
1% of rated capacity . . . but don't know without measuring.
Is there a way to adjust this point to allow it to stay in absorb for
a longer time?
Haven't had a 1562 (or replacement) apart to find out.
But even if the EOAC termination value is higher, I'm
not convinced that you're going to loose much. We could
set up the experiment and find out.
Bob . . .
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Subject: | Re: Charger needed to revive 18 aH Lead Acid |
Batteries
If it's 100mAs or less that may just be the ticket to success.
Yes.
Just for grins, I took one of the 12a.h. batteries I
bought from you that has been on a Battery Tender
for the last several days (green light on, in maintenance
mode. Fooey, didn't read the float voltage first) and
hooked it to a 14.6v power supply. Charge current jumped
to 300mA and over the next 12 minutes it fell to 100mA.
Another data point. After one hour at 14.6 volts, current
going into the battery is still about 90mA. This suggests
to me that the battery has stopped converting incoming
energy into changes in chemistry and that 100mA may
indeed be too large a value for marking end-of-absorption-
charge cycle. The values you deduced for the Chargtek
device of 200-300 mA may indeed be more practical.
Bob . . .
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