Today's Message Index:
----------------------
1. 04:26 AM - Re: Re-juvinate a NiCad Battery? (rparigor@suffolk.lib.ny.us)
2. 06:40 AM - Re: Re-juvinate a NiCad Battery? (Robert L. Nuckolls, III)
3. 07:00 AM - Re: Re-juvinate a NiCad Battery? (David)
4. 07:18 AM - Re: Fw: Re: Fw: Coolie Hat Switch (Bob McCallum)
5. 07:38 AM - Re: Fw: Re: Fw: Coolie Hat Switch (Robert L. Nuckolls, III)
6. 07:43 AM - Re: Re-juvinate a NiCad Battery? (Robert L. Nuckolls, III)
7. 09:13 AM - Re: Lamar DSX1240-1 Alternator (Jeff Page)
8. 11:00 AM - Re: Re-juvinate a NiCad Battery? (Ken)
9. 01:51 PM - Re: Fw: Coolie Hat Switch (Jeff Page)
10. 04:23 PM - ShopGoodwill.com (Eric M. Jones)
11. 06:35 PM - Spring Cleaning (Harley)
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Subject: | Re: Re-juvinate a NiCad Battery? |
Hi Group
A few notes on NiMh batteries:
I've done quite a bit of testing on AA and AAA NiMh batteries lately
and one theme that seems to ring true is by knowing the weight you can
pretty much predict what sort of cell you have. I was running an average
50mA, 5 paralleled LED load (only 1 resistor) on three series AA
batteries. It didn't matter if it was LSD or Non LSD, what ever the
weight is of a Home Depot AA Energizer LSD cell, if you have about that
weight you will get about 2100mAs of capacity. From Home Depot they are
about 3$ each but if you shop hard on E-Bay you can get them for ~ 2$
each delivered. I purchased a half dozen different cells from E-Bay
ranging from $.59 to $.79 each. Some have very beautiful packaging, but
they all have written on them 3,000mA. After several C/10 for ~15 hour
cycles they range in capacity from 600mAsa to ~900mAs with the 600s being
lighter in weight than the 900s. Essentially the 600s are AAA "good
stuff' squeezed into a AA wrapper. I also set up a fast discharge
test and for the most part the lighter the cell the less ability it had
to hold up to a high amp draw. That said I did test some Elite batteries
that are Non-LSD cells that have the ability to dump amps at a much
higher rate than the Energizers. They claim they can take a 15 to
25 amp draw:
http://www.cheapbatterypacks.com/product/122/Elite-2000-AA.aspx and it
seems like the best AA NiMhs I've tested thus far as far as their
ability to dump. I haven't flown a model with them, but suspect they
will be pretty good at short bursts of 15 to 20 amps, pretty amazing.
When you abuse cells beyond belief you want to see them stay above 1V for
most of the cycle. They don't like to be fast peak charged though,
best stay at 1C or 1.5C and you better have very low resistance
connections and wires charging anything over ~ .75C (C being the Capacity
of the battery). The capacity on the Elites is just ~ 2,000 mAs at my 50
mA draw where the Energizers are ~ 2100 mAs. BTW it's not a very good
idea to take series NiMhs much below 1V. If the cells get out of balance
and you have one that gets very discharged, the other cells are not going
to do it any good for it's long life at all. With my 50mA load, there
is very little capacity loft at 1V. If you test cells after you cycle
them a few times, if you know the temperature and are using a 50mA load,
then you can pretty easily tell if they are more or less than 75%
charged. At room temp if you are seeing over 1.4 volts, you can be pretty
sure you have over 90% capacity. If your over 1.35 volts then you are
probably over 75%. Again this is with a 50mA load. Much below the 1.35
volt area it begins to get tricky. Different cells can be slightly higher
or lower. There is a very long voltage hold out between ~ 1.2 and 1.35
volts so using voltage to figure out how much capacity is left will not
be very accurate. Knowing if you are over 75% however is very useful! I
forget the voltage, but once you see the voltage drop to ~ 1.15 volts,
there isn't much capacity left.
I set up a fast discharger to get cells quickly down to 1V with a 3 ohm
resistor. I began with 3 paralleled 3 ohm, got to 1V, removed one 3 ohm
resistor, got to 1V removed a second resistor, then got to 1V using only
the one 3 ohm resistor and let it get to 1V. Now i have a known state of
discharge. Using Bobs one LM1117 with a fixed resistor, three in parallel
off a 12 volt battery, I can charge 6 AA cells in about 45 minutes on a
timed charge. I cheat a little, I have 3 series for about the first half
of the charge, then go down to 2, then complete with one. This is a low
cost fast charger for third world countries. If they have the time a
better way is to C/10 for 14 to 16 hours. With my fast charger I have it
down where I get them 90 to 95% charged with very little chance of
venting. Once a NiMh cell peaks, if you continue with a constant current
charge the cells begin to warm up. With my pseudo 3 stage charge they
barely get Luke warm at the end of the charge! BTW 1/2" PVC
tube works great as a AA holder. I did drill holes making it a piece of
swiss cheese for cooling when fast charging, but you could probably get
away with only two 1/4" holes per cell in case they vented.
I built a pedal powered generator to charge up the 12volt battery that
can use any bicycle, Home Depot 5 gallon buckets and a permanent magnet
air conditioner blower motor for a car. I also top off my Odyssey PC545
aeroplane battery with it. The Odyssey is pretty amazing as far as
it's ability to not self discharge. If anyone is not totally
bored here's some videos:
http://communitysolutionsinitiative.org/2011/09/24/light-cycle-videos/
If anyone wants to make a pedal powered generator, here's step by
step instructions:
http://www.europaowners.org/main.php?g2_itemId=89553
Pepboys PM102X permanent magnet motor costs $19.99 the last time I bought
one. Some have tried PM102 either with nothing or a different letter at
the end, and they may be reverse wound. They work OK you just need to
reverse the wires. Using a Schottky diode prevents the motor from running
off the battery and only loses a few percent to heat. I was using Rat
Shack diodes until the Schottkys came in and they lose more to heat.
One more thing, I love AstroFlight Whatt Meter (Whatt is correct):
http://www.astroflight.com/index.php?main_page=index&cPath=2
You can keep them alive with 4 NiMh or Alkaline batteries and measure
down to and datalog even 1 cell. Expensive though.
I fooled with these at half the price and as long as you can wait half of
forever (they only build when they have enough orders):
http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10080
They are a pretty good value. They happen to have in stock at the moment!
Probably not quite as accurate as the Astroflight though.
Ron P.
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Subject: | Re: Re-juvinate a NiCad Battery? |
At 06:24 AM 3/9/2012, you wrote:
>Hi Group
>
>A few notes on NiMh batteries:
>
>I've done quite a bit of testing on AA and AAA NiMh batteries lately
>and one theme that seems to ring true is by knowing the weight you
>can pretty much predict what sort of cell you have.
<snip>
>They are a pretty good value. They happen to have in stock at the
>moment! Probably not quite as accurate as the Astroflight though.
>
>Ron P.
I'll add weight measurements to the gathered
data on any future testing I do with the metal
batteries. It probably wouldn't have been a useful
data point with the AA alkaline cells . . . at the
time I ran the first tests, there was little difference
of significance in performance over the spectrum of
products evaluated. I expect to see more differences
in the metal world and weight may well be an important
predictor. I do recall picking up a D cell
that seemed too light and then observed that it was
rated more like the family of C cells. At least
they were honest about it.
Great data sir! I'm archiving this piece in my
"battery performance" folder. When I update the
AA battery article, I'd like to collaborate with
you to add your findings to the knowledge base.
Bob . . .
Message 3
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Subject: | Re: Re-juvinate a NiCad Battery? |
Along these battery lines, why can't we recharge these new lithium
AA's? That would cut battery buying to about a tenth...
David M.
Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 03:55 PM 3/8/2012, you wrote:
>>
>> Also, be advised that some of the dirt cheap batteries (and even some
>> full priced ones) are scams. They hold very little battery material
>> and last only a very short time. Think of the batteries that "are
>> included" with some of the cheap toys, for example. Some of those
>> have made it into the mainstream marketplace. Caveat Emptor.
>
> Yeah . . . you can find Ni-Cd and Ni-Mh AA cells rated
> with over 2:1 differences in capacity. It would be
> interesting to do the How Bad Can a Metal Battery Be?
> experiment on some of these cells.
>
> I've also noted that many so-called Ni-Cd "D" cells
> are a bit . . . shall we say . . . light? They
> are also rated in the 1500 to 2000 mAh range commensurate
> with a "C" cell. I think these batteries would be
> a disappointment too . . . a real Ni-Cad "D" is good
> for about 4000 mAh.
>
> The computer and DAS I used on the original battery
> killer experiments bit the dust a couple of years ago.
> I've got a new set of tools that I need to adapt to a
> battery box that holds at least 8 cells for testing at
> a time.
>
> I'm debating whether to stay with the original testing
> protocol for the AA alkaline cells that used a fixed
> resistor. Certainly good enough for comparative
> studies. I think I'd like to fit the test set with
> software controlled loads . . . probably power fets.
> This would let me run a wide range of discharge currents.
> It would also allow modulation of the test current
> during a discharge cycle to measure the cell's internal
> resistance. Dynamic loads would also let me discharge
> in a constant resistance, constant current or constant
> power modes. I need to talk to my software guy and see
> if he's up to making this hardware 'hum'. I'm not going
> to have time to do it for awhile.
>
> But you're quite right. What's marked on the label may
> not be all it claims to be.
>
>
> Bob . . .
>
>
--
Tell the truth. Be honest. Be responsible to and for yourself.
We want our freedoms back. Strike the illegal legislations called: 1) obamacare,
2) "Patriot (HA!) Act", and 3) 'presidential orders' that affect anyone besides
gubmnt worker bees.
Hate crime laws? Really? Thought police? Orwell would be proud.
Every gram of cocaine you buy from elsewhere contributes to an innocent being murdered
in Central and South America. Grow your own or Stop taking it.
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Subject: | Re: Coolie Hat Switch |
At a quick glance there appears to be a slight error in the circuit as
posted. (possibly a result of that 2:00AM thing?) It appears that the "up"
and "down" functions on the input switches control both the pitch and roll
circuits and the "left" and "right" functions serve no purpose?? Or am I
misreading something??
Bob McC
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-
> server@matronics.com] On Behalf Of Robert L. Nuckolls, III
clip
> Now you dun it . . . got started on a good idea
> last night and couldn't put it down until after 2
> a.m.
>
> Here's a first pass at an all solid state, two channel
> relay deck and trim speed controller for a pair of
> Ray-Allen trim actuators. It features adjustable
> rates for both pitch and roll trim, dual inputs from
> pilot and copilot stick grips, conflicting command
> lockout, 10 to 30 volt input so it can be used on both
> 14 and 28v systems, AND . . . it will only load the
> trim-switch contacts very lightly . . . about 20 mA.
>
> http://www.aeroelectric.com/Misc/7299_Ray-Allen_Relay-Deck_Schematic.pdf
clip
> Bob . . .
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Subject: | Re: Coolie Hat Switch |
At 09:18 AM 3/9/2012, you wrote:
><robert.mccallum2@sympatico.ca>
>
>At a quick glance there appears to be a slight error in the circuit as
>posted. (possibly a result of that 2:00AM thing?) It appears that the "up"
>and "down" functions on the input switches control both the pitch and roll
>circuits and the "left" and "right" functions serve no purpose?? Or am I
>misreading something??
Good eye sir! It's pretty easy to let 'big picture'
items get by you while squinting at it on the screen.
I printed the drawing on a nice big 11 x 17 piece
of paper last night to start combing the nits and
assigning part values. I found exactly what you've
described and corrected it.
You're right on track my friend. If anyone else feels
motivated to sift the sands of this effort and post
their questions/findings, it would be much appreciated
. . . it's always good to have several pairs of eyes
looking for disconnects between design goals and the
practical physics. Thanks!
I've posted the latest iteration to the server.
http://aeroelectric.com/Pictures/Schematics/7299p1_Ray-Allen_Relay-Deck_Schematic.pdf
Bob . . .
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Subject: | Re: Re-juvinate a NiCad Battery? |
At 08:31 AM 3/9/2012, you wrote:
>
>Along these battery lines, why can't we recharge these new lithium
>AA's? That would cut battery buying to about a tenth...
>
>David M.
For reasons similar to those that keep you from
recharging say a Pink Bunny cell or a legacy carbon
zinc cell. For a electro-chemistry system to be
driven in reverse takes special attention to it's
makeup. There ARE alkaline cells designed to be
recharged. I've never used any but I've been curious
about them. I may add them to the roster of test
subjects.
The short answer is that the designers of a given
cell make adjustments to optimize the cell's performance
characteristics in perhaps one or two features.
Making a cell optimally rechargeable probably gives
up some other performance feature.
Bob . . .
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Subject: | Re: Lamar DSX1240-1 Alternator |
> Modifying this circuit would be difficult. Much easier to delete the
> regulator in favor of an external one. Even easier still is selling
> the existing alternator and purchasing a more suitable one, which is
> what he has decided to do.
Good. It's is difficult sometimes to make
a useful trade between multiple solutions
without have a good grasp of the "big picture".
It's easy to be distracted by what one might
call false economics. E.g., a cousin of mine
was recipient of a nice Lincoln 4-door. He
was in tall cotton until something broke. My
first 'good' car was a '57 Chevy BelAire
with all the goodies. I too was riding high
until something broke. My next car was a '59
6-cyl, stick shift with a good heater and
crank windows. Best return-on-investment in
transportation I ever made. In spite of 1/2
the gas mileage, my total cost of ownership
per mile traveled was less than buying a
new Volkswagon Bug.
Availability of small externally regulated
alternators is limited. I just checked the
MPA catalog for single-tension, two-pivot
externally regulated alternators. Couldn't fine
anything under 90 amps. Doing the internal-to-
external mod isn't real difficult. How much
money does he have tied up in the alternator
he has?
I think he plans to buy the B&C 40A alternator and the external
regulator/overvoltage protection products, which I think are twice the
cost of the alternator he bought from the engine shop.
Although the risk is low, if a runwaway alternator took out his
avionics and EFIS system, saving those few hundred dollars would seem
like a pretty poor choice.
Even if he modifies the alternator he has, he still needs to purchase
the external regulator/over voltage anyway.
Since he has less electrical experience than those of us on this list,
buying a product that requires no special modifications is an
expedient option.
Jeff Page
Dream Aircraft Tundra #10
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Subject: | Re: Re-juvinate a NiCad Battery? |
FWIW I've found rechargeable alkaline to be fine for low current devices
such as remote controls. However after a couple of charges they are poor
to non functional in anything that requires a bit of current such as a
camera or anything with a motor in it. This experience is from perhaps
20 AA cells over several years.
Ken
On 09/03/2012 10:42 AM, Robert L. Nuckolls, III wrote:
> At 08:31 AM 3/9/2012, you wrote:
>>
>> Along these battery lines, why can't we recharge these new lithium
>> AA's? That would cut battery buying to about a tenth...
>>
>> David M.
>
> For reasons similar to those that keep you from
> recharging say a Pink Bunny cell or a legacy carbon
> zinc cell. For a electro-chemistry system to be
> driven in reverse takes special attention to it's
> makeup. There ARE alkaline cells designed to be
> recharged. I've never used any but I've been curious
> about them. I may add them to the roster of test
> subjects.
> The short answer is that the designers of a given
> cell make adjustments to optimize the cell's performance
> characteristics in perhaps one or two features.
> Making a cell optimally rechargeable probably gives
> up some other performance feature.
> Bob . . .
>
>
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Subject: | Re: Fw: Coolie Hat Switch |
> Here's a first pass at an all solid state, two channel
> relay deck and trim speed controller for a pair of
> Ray-Allen trim actuators.
> http://www.aeroelectric.com/Misc/7299_Ray-Allen_Relay-Deck_Schematic.pdf
Bob,
Just wondering if it is practical to fail-safe a failure of the H-bridge ?
Is there a tiny fuse that could be soldered to the circuit board in
case the H-bridge shorts out ?
What about integrating a "master disconnect" pulse from an external
push button ?
Jeff Page
Dream Aircraft Tundra #10
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Subject: | ShopGoodwill.com |
I want to share with you a little gem:
Ebay has lots of stuff, but it's hard to beat the bargains at ShopGoodwill.com.
For one thing, it's all tax deductible (I think) for another, it helps people
who really need help, and it's a good way to waste time. There are bargains galore.
Recently, I have seen plenty of things that would be of use to a/c builders. I
have seen instruments and tools galore go for a song. Often the descriptions are
muddled, and you never know what condition your purchase will be in. I have
made some amazing deals, and have seen even more amazing deals.
One curiosity is that many estates get transferred wholesale to Goodwill industries
without the kids (if there are any) really caring about--for example--the
old man's David Clarke headphones. Or the garage full of aircraft instruments.
Search tools and miscellaneous.
And oh yeh, if you want a digital camera for no money. Buy one of theirs. I've
bought several and have given them away to the kids.
I bid unsuccessfully on a box of SIX Nikon Ultra-Micro Nikkors, used for IC fabs
(but also collected and used for really-amazing photos, by those in the know...).
Each of these sells on Ebay for $3,000. Woulda' Shoulda'....
But unlike Ebay, where things are pretty well organized, ShopGoodwill is like a
huge thrift store. You just look around.
Example: Dyna-Glo RMC-FA100A Propane Heater (9529840) sitting at $12.10. Now who
above the 30th parallel doesn't need one for his hangar?
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=368083#368083
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Started my spring hangar cleaning early today. I've put a number
of items on eBay, some brand new and some used. Some instruments
and some hardware. And one very unusual altimeter! For some of
us, anyway <G>
For those who are musically inclined, I am even offering a
vintage guitar. So you can spend those lonely, rainy days
entertaining your fellow pilots around the campfire! Just don't
start the campfire INSIDE your hangar!
You can see them all here: http://tinyurl.com/7darnnb
Have a look...there just might be something you've been looking
for...
Harley Dixon
Long EZ N28EZ
Hangar 29
Canandaigua Airport
Canandaigua, NY
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