AeroElectric-List Digest Archive

Fri 03/09/12


Total Messages Posted: 11



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)
 
 
 


Message 1


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    Time: 04:26:47 AM PST US
    Subject: Re: Re-juvinate a NiCad Battery?
    From: rparigor@suffolk.lib.ny.us
    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.


    Message 2


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    Time: 06:40:38 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    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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    Time: 07:00:58 AM PST US
    From: David <ainut@knology.net>
    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.


    Message 4


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    Time: 07:18:44 AM PST US
    From: Bob McCallum <robert.mccallum2@sympatico.ca>
    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 . . .


    Message 5


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    Time: 07:38:52 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    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 . . .


    Message 6


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    Time: 07:43:40 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    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 . . .


    Message 7


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    Time: 09:13:11 AM PST US
    From: Jeff Page <jpx@qenesis.com>
    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


    Message 8


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    Time: 11:00:58 AM PST US
    From: Ken <klehman@albedo.net>
    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 . . . > >


    Message 9


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    Time: 01:51:43 PM PST US
    From: Jeff Page <jpx@qenesis.com>
    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


    Message 10


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    Time: 04:23:30 PM PST US
    Subject: ShopGoodwill.com
    From: "Eric M. Jones" <emjones@charter.net>
    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


    Message 11


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    Time: 06:35:59 PM PST US
    From: Harley <harley@AgelessWings.com>
    Subject: Spring Cleaning
    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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