Today's Message Index:
----------------------
1. 07:02 AM - Re: old B and C SD-8 Dynamo failure (Robert L. Nuckolls, III)
2. 09:32 AM - Today's trivia dump . . . (Robert L. Nuckolls, III)
3. 11:13 AM - Re: Today's trivia dump . . . (C&K)
4. 11:13 AM - Re: Today's trivia dump . . . ()
5. 02:15 PM - Re: Today's trivia dump . . . (Eric Page)
6. 02:35 PM - Re: Today's trivia dump . . . (Stuart Hutchison)
7. 03:00 PM - Re: Today's trivia dump . . . (Robert L. Nuckolls, III)
8. 03:05 PM - Re: Today's trivia dump . . . (Robert L. Nuckolls, III)
9. 11:12 PM - Re: Today's trivia dump . . . (Eric Page)
Message 1
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| Subject: | Re: old B and C SD-8 Dynamo failure |
>
>
>I'll get the dynamo and regulator off to you within the next couple of
>days, using your PO Box 130 address unless you instruct otherwise.
>
>Thanks for looking at this. If it checks out OK, I guess it'll mean
>that I missed a faulty connection somewhere that got cleared up with the
>replacement. After all these years of flawless service, I can't decide
>whether I'm rooting for the dynamo or me!
Thank YOU for making it available. It's a rare
treat to get field returns on mature designs
for evaluation. Products I designed at Electro-Mech
were routinely serviced in house as E-M was the only
FAA qualified overhaul and repair shop for those
products . . . I was able to visit my former
colleagues at E-M and look through the R/R
records.
In the OBAM aviation world it's more difficult
to access such data.
Bob . . .
Message 2
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| Subject: | Today's trivia dump . . . |
I think I've written about a project to repeat the
experiment I did on AA alkaline cells 14 years ago . . .
http://tinyurl.com/mhztc2b
I've been keeping a constellation of AA-cell products
in the super-duper-battery-runner-downer for several
weeks and at first blush at most of the data, the
original deductions about alkaline cell quality vs.
costs and advertising hype haven't changed.
There are a couple interesting things I've discovered
that I'll share with the List.
There's a line of alkaline cells purported to be
enhanced with lithium. A noteworthy example is
the Energizer 'Advanced Lithium' brand. These
are not lithium-ion cells . . . they still present
the expected 1.6 volt/cell open circuit potential
as their rudimentary cousins but unlike MOST 'enhanced
formulas' these do indeed offer improved performance in the
same envelope.
The energy traces below show a generic pair of alkaline
AA cells that have delivered ~1.4 Watt-Hrs of energy . . .
about the same numbers as the first experiment in 2002.
Then we have a trio of traces that have delivered 3.6
Watt-Hrs of energy or about 2.5 times that of the
non-lithium cell.
There are three additional traces of interest . . . they
too are generated by the discharge test of some advanced
lithium cells. The general shape of the curves are the
same as for the first three described above . . . but they
averaged a 15% lower value of delivered energy and the output
voltage is 'ragged' or unstable.
Emacs!
This is caused by tiny amounts of resistance introduced
by the connections to the test equipment that can arise when
the cells are connected with the spring-loaded holders
common to 99.999% of all cylindrical cell powered products.
Emacs!
These resistance values are small . . . and generally have
little effect on appliance performance for applications
with smaller current demands. The tests I'm conducting use
a 300 mA constant current discharge rate. At this rate . . .
and anything higher . . . there is a potential for battery
holder resistance to degrade system performance.
This fact is part of the foundation for why I explored
and ultimately recommended the 9v alkaline cells in a standby
battery application a few days ago. The very low current
demand in the application under discussion did not exclude
the 9V cell.
Obviously, the AA cell offers a larger energy bucket for
such tasks . . . but getting a firm electrical grip on
the cell's electrical energy is a bit more problematic.
My energy studies are being conducted with cells having
SOLDERED leads eliminating the holder issues . . .
indeed, one could build up disposable cell arrays using
similar techniques. But they need to be done with care
lest the cells be damaged by soldering heat.
It would be really cool to use tab-welders common the Ni-Mh
and Li-Ion arrays. The AA alkaline cell has a really small
(+) terminal . . . more difficult to weld on. I have some
alkaline D-cell arrays for video cameras that were welded . . .
but the AA-cell is more problematic.
I may do an article on the techniques I use for soldering
to AA-cell . . . it's not difficult.
It seems that the past few weeks discoveries in my AA-cell
testing offer another choice for DIY standby battery
construction. As soon as I've squashed all the energy
out of the current constellation of test articles, I'll
do some testing on the effects of soldered leads.
Watch this space . . .
Bob . . .
Message 3
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| Subject: | Re: Today's trivia dump . . . |
Good to see some quantified info on the advanced li alkalines.
While I've soldered a number of tabs on alkaline batteries it seems that
DIY tab welders are somewhat common for building battery packs. In the
crudest form, just two handheld copper wire "electrodes" fed by a lead
acid battery. More advanced units are AC powered using a few volts from
a couple of secondary turns on an old transformer and timed current
pulses. Two pulses of 50 ms or so each from what I've learned so far.
Ken
Message 4
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| Subject: | Today's trivia dump . . . |
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Message 5
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| Subject: | Re: Today's trivia dump . . . |
For anyone interested in this project, search YouTube for "MOT spot welder" and
you'll find a number of videos on the subject of using a microwave oven transformer
(MOT) to build a spot welder.
Eric
> On Apr 6, 2017, at 11:10 AM, C&K <yellowduckduo@gmail.com> wrote:
> While I've soldered a number of tabs on alkaline batteries it seems that DIY
tab welders are somewhat common for building battery packs. In the crudest form,
just two handheld copper wire "electrodes" fed by a lead acid battery. More
advanced units are AC powered using a few volts from a couple of secondary turns
on an old transformer and timed current pulses. Two pulses of 50 ms or so
each from what I've learned so far.
Message 6
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| Subject: | Re: Today's trivia dump . . . |
At around 3200mAh, the energy density of typical Lithium primary
(non-rechargeable) cells - which are not the same as Li-Ion secondary
(rechargeable) technology - is only about 15% more than a typical
quality Alkaline cell (about 2800mAh). The reason for the claims of 5-7
times longer lasting in high-energy devices is the C-rate. In other
words, Lithium cells can deliver their stored potential at a higher rate
of current without increasing internal resistance and getting hot.
Energy can neither be created nor destroyed, so when Alkaline cells used
in high-energy devices get hot, the heat represents a =98loss=99
or waste of stored energy from the cell itself. So, it is not that
Lithium cells have 5-7 times more stored energy density (commensurate
with the price difference), but Lithium cells can deliver much more of
their energy without the wasting it as heat. Putting Lithium batteries
in a very low drain wall-mounted clock would be pointless, but in my
Infra-Red Night Vision hunting scope they are excellent value for money.
V/R Stu
> On 7 Apr 2017, at 04:10, <jim@poogiebearranch.com>
<jim@poogiebearranch.com> wrote:
>
> Bob,
>
> Thanks for this update. I had been really wondering if those Energizer
"Advanced Lithium" batteries were worth the extra cost. I just did a
lookup on Amazon to find the current pricing for the AA cells =93
seems to be around $1.27 each (cheapest I could find). By comparison,
the Kirkland brand alkaline cells from CostCo run about $0.25 per cell.
Even if the "Lithium" cells last 3 times longer, they still cost 5 times
as much! Looks like your old advice from 2002 still rings true: "Buy
cheap and change often!"
>
> By the way, I recently went on a lengthy cross-country trip in my '65
Champion 7ECA (pre-dates the "Citabria" name...) only to have the PTT
wiring under the stick the short out. That gave me a "hot mike" until I
shut off the aircraft radio. I switched over to my SP-400, which had an
alkaline battery pack installed that had already been used for 4+ hours
last year at OSH (listening to the Sunday arrivals). That pack lasted
another 4+ hours of "normal" use in the cockpit before the SP-400 would
no longer transmit. I keep a spare battery pack loaded and ready to go
(the only reason I didn't put new batteries in the 1st pack), so I
switched to the new pack to complete the flight. The "new" batteries
show a "full" charge on the SP-400 battery meter after about an hour of
use in flight.
>
> By the way, with the SP-400 connected to a dedicated coax and external
VHF comm antenna and a headset adapter, I was able to talk to both
enroute ATC and our local tower from 15 miles away pretty clearly, with
only a bit of "scratchiness" at 20 miles (still understandable to them,
though). Reception-only range was well over 30 miles.
>
> Jim Parker
>
>
> -------- Original Message --------
> Subject: AeroElectric-List: Today's trivia dump . . .
> From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com
<mailto:nuckolls.bob@aeroelectric.com>>
> Date: Thu, April 06, 2017 11:29 am
> To: aeroelectric-list@matronics.com
<mailto:aeroelectric-list@matronics.com>
>
> I think I've written about a project to repeat the
> experiment I did on AA alkaline cells 14 years ago . . .
>
> http://tinyurl.com/mhztc2b <http://tinyurl.com/mhztc2b>
>
> I've been keeping a constellation of AA-cell products
> in the super-duper-battery-runner-downer for several
> weeks and at first blush at most of the data, the
> original deductions about alkaline cell quality vs.
> costs and advertising hype haven't changed.
>
> There are a couple interesting things I've discovered
> that I'll share with the List.
>
> There's a line of alkaline cells purported to be
> enhanced with lithium. A noteworthy example is
> the Energizer 'Advanced Lithium' brand. These
> are not lithium-ion cells . . . they still present
> the expected 1.6 volt/cell open circuit potential
> as their rudimentary cousins but unlike MOST 'enhanced
> formulas' these do indeed offer improved performance in the
> same envelope.
>
> The energy traces below show a generic pair of alkaline
> AA cells that have delivered ~1.4 Watt-Hrs of energy . . .
> about the same numbers as the first experiment in 2002.
>
> Then we have a trio of traces that have delivered 3.6
> Watt-Hrs of energy or about 2.5 times that of the
> non-lithium cell.
>
> There are three additional traces of interest . . . they
> too are generated by the discharge test of some advanced
> lithium cells. The general shape of the curves are the
> same as for the first three described above . . . but they
> averaged a 15% lower value of delivered energy and the output
> voltage is 'ragged' or unstable.
>
>
> <13684fd9.jpg>
>
> This is caused by tiny amounts of resistance introduced
> by the connections to the test equipment that can arise when
> the cells are connected with the spring-loaded holders
> common to 99.999% of all cylindrical cell powered products.
>
> <13685027.jpg>
>
> These resistance values are small . . . and generally have
> little effect on appliance performance for applications
> with smaller current demands. The tests I'm conducting use
> a 300 mA constant current discharge rate. At this rate . . .
> and anything higher . . . there is a potential for battery
> holder resistance to degrade system performance.
>
> This fact is part of the foundation for why I explored
> and ultimately recommended the 9v alkaline cells in a standby
> battery application a few days ago. The very low current
> demand in the application under discussion did not exclude
> the 9V cell.
>
> Obviously, the AA cell offers a larger energy bucket for
> such tasks . . . but getting a firm electrical grip on
> the cell's electrical energy is a bit more problematic.
>
> My energy studies are being conducted with cells having
> SOLDERED leads eliminating the holder issues . . .
> indeed, one could build up disposable cell arrays using
> similar techniques. But they need to be done with care
> lest the cells be damaged by soldering heat.
>
> It would be really cool to use tab-welders common the Ni-Mh
> and Li-Ion arrays. The AA alkaline cell has a really small
> (+) terminal . . . more difficult to weld on. I have some
> alkaline D-cell arrays for video cameras that were welded . . .
> but the AA-cell is more problematic.
>
> I may do an article on the techniques I use for soldering
> to AA-cell . . . it's not difficult.
>
> It seems that the past few weeks discoveries in my AA-cell
> testing offer another choice for DIY standby battery
> construction. As soon as I've squashed all the energy
> out of the current constellation of test articles, I'll
> do some testing on the effects of soldered leads.
>
> Watch this space . . .
>
> Bob . . .
Message 7
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| Subject: | Re: Today's trivia dump . . . |
At 04:31 PM 4/6/2017, you wrote:
>At around 3200mAh, the energy density of typical
>Lithium primary (non-rechargeable) cells - which
>are not the same as Li-Ion secondary
>(rechargeable) technology - is only about 15%
>more than a typical quality Alkaline cell (about
>2800mAh). The reason for the claims of 5-7
>times longer lasting in high-energy devices is
>the C-rate. In other words, Lithium cells can
>deliver their stored potential at a higher rate
>of current without increasing internal
>resistance and getting hot. Energy can neither
>be created nor destroyed, so when Alkaline cells
>used in high-energy devices get hot, the heat
>represents a =98loss=99 or waste of stored
>energy from the cell itself. So, it is not that
>Lithium cells have 5-7 times more stored energy
>density (commensurate with the price
>difference), but Lithium cells can deliver much
>more of their energy without the wasting it as
>heat. Putting Lithium batteries in a very low
>drain wall-mounted clock would be pointless, but
>in my Infra-Red Night Vision hunting scope they are excellent value for
money.
>
>V/R Stu
I have encountered AA cells offered with creative
advertising hyperbole . . . and found them to
be short on snort.
However, the cells I posted about earlier today
were discharged on an well instrumented, 300 mA
constant current load. So irrespective of the
cell's c-rate, I was comparing the various
offerings under identical test conditions.
I'll do some more detailed comparisons of these
cells and get some internal resistance measurements
at various points along their discharge profiles.
Bob . . .
Message 8
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| Subject: | Re: Today's trivia dump . . . |
At 04:11 PM 4/6/2017, you wrote:
>
>For anyone interested in this project, search YouTube for "MOT spot
>welder" and you'll find a number of videos on the subject of using a
>microwave oven transformer (MOT) to build a spot welder.
I've seen those . . . while economical in
terms of purchased materials, they're kinda
labor intensive. I'm toying with the notion
of trying one of these.
http://tinyurl.com/knl5wrf
Bob . . .
Message 9
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| Subject: | Re: Today's trivia dump . . . |
Indeed; plus the dangers inherent in a mains-powered project.
I hadn't yet seen the eBay item you linked. The Chinese manufacturers never cease
to amaze with their ability to crank out high-dollar items at bargain basement
prices.
This got me thinking about a simple way to accomplish this with stuff we might
have on hand at the bench or could get cheap-and-quick. With the idea that lead-acid
batteries are ubiquitous, safe and able to provide ample current to weld
the tiny spots needed to secure battery tabs, here's what I came up with:
http://preview.tinyurl.com/knz5te2
...using a solenoid like this:
http://preview.tinyurl.com/n88f7tl
This could probably be lashed together in half an hour, for a few dollars in parts.
Thoughts?
Eric
Robert L. Nuckolls, III wrote:
>
> I've seen those . . . while economical in terms of purchased materials, they're
kinda labor intensive. I'm toying with the notion of trying one of these.
>
> http://tinyurl.com/knl5wrf
>
> Bob . . .
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=468112#468112
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