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Old Apr 17, 2012, 12:50 PM
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Originally Posted by gravityKills View Post
As the German proverb goes "wer viel misst, misst viel Mist" (he who measures a lot measures a lot of BS).
This threads previous 15th page is again just another ongoing example that there is more complexity surrounding John's SimpleTool that can do as much to confuse the "average modeller" (John) as well as the "relatively advanced hobbyist" (Wayne) than help him get the best performance/usability from his lottery packs. For all their notable good efforts the time spent with all this figuring isn't practical or necessary. A thorough pre-flight conditioning of any LiPo lottery pack will quickly determine its usability with a good balancing charger ... without the need for an ESR and having to determine the FOM of a questionable lottery pack.

Then it’s up to the average modeler and the relatively advanced hobbyist to properly utilize/care for their packs, whether they be lipos more like some of Wayne’s lottery packs from a leading Chinese distributor or Li-Polys more like some of Charles’ packs from a leading American distributor.

Wayne, John, and Mark may thrive on the challenging calculated complexity for finaling arriving at a pack's truly meaningful IR calculation ... assuming it's all being done well and good to some agreed upon industry standard OR John and Wayne's agreed upon standard. It's possible that Charles finds all this figuring, figuring, figuring to be just a little too much to expect from your average modellers as well as your relatively advanced hobbyist and therefore not really as necessary as some here may/are being led to believe.

So, the real party guilty of any possible "nit-pickin" isn't Gitchee Gumee, but more like WJM.
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Old Apr 17, 2012, 01:21 PM
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Microwave has a sneaky contribution to this thread, with a very low C rating
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Old Apr 17, 2012, 01:37 PM
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Thank you, RCG, for the "Ignore List" function.

And thank you again Mark, Wayne, John, and others for your invaluable contributions.
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Old Apr 17, 2012, 01:44 PM
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Quote:
Originally Posted by Wayne Giles View Post
Apologies for posting an old plot again but if you look at :
http://www.rcgroups.com/forums/attac...mentid=3623546

You will see that different lipos have a different temperature coefficient.

From the graph we can assume that the change is linear over a small change so that at 20degC the change for pack B is 1.3%/degC but for packC it is 3.2%/degC so that we cannot use an exact factor.
If forced to estimate, I would guess that a reasonable approximation would be about 1.5 - 2%/degC at around the 20degC area ( about 1%/deg.F at around the 70degF area)
We are only estimating here so the errors are not massive provided you don't try to correct for a large temp difference ie >3degC

The most accurate way is to soak at the correct temperature for a couple of hours!

Wayne
Much appreciated, thank you Wayne. I find it quite fascinating that the gradient of the IR/temp curve should be so characteristic for a given pack/manufacturer, almost like a signature of the specific chemistry (?).

Is there a particular significance associated with 22'C, or is it an arbitrary temperature that was picked as a good average number on which to base reporting results?

Thanks again.
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Old Apr 17, 2012, 02:02 PM
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22 deg C is entirely my fault.

It just so happens to be the controlled temperature of my laboratory (hobby room). It's also the recognized average temperature of indoor controlled environments (at least in the US) so it is expected to be easiest to achieve throughout the world.

For one's own tracking purposes, any temperature is fine as long as you are consistent. For broader comparative and database reporting purposes, the 22 deg C standard is required to ensure data integrity.

Mark
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Old Apr 17, 2012, 03:00 PM
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Originally Posted by TreeDiver View Post
yes indeed.
room temp should be the same, each time you measure

22degrees, to have values that can be shared with others:
It's not that simple.
First, the temperature coefficients are widely varying, the curves even cross. This alone should give you pause. The picture speaks a very clear language regarding the usefulness of IR as advocated here.

Second, with the plot in mind you'll want to control your temperature quite accurately, and it will take a long, long time before a big pack such as 6s5000mAh reaches a homogenous temperature.
Note, the overall cell resistance is not simply the average over the area. That would be too optimistic, since different areas of the cell are in parallel, not in series.
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Old Apr 17, 2012, 03:07 PM
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Originally Posted by TreeDiver View Post
some have a sneaky contribution to this thread, with a very low C rating
PS if you have to say something to somebody, why not say openly who you are addressing? Weasel words like "some" make at least me wonder, whether you are trying to dodge responsibility for your actions.
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Old Apr 17, 2012, 03:22 PM
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Originally Posted by Harry D View Post
Thank you, RCG, for the "Ignore List" function.
Great advice! There's one way to instantly improve an already great thread!

I know of at least two that will get the honor of being added to my ignore list. I have been waiting for them to add something worthwhile but it's been all drivel so far.

John, Mark, Wayne,

I have been using the tool and one of my iCharger 306B's to categorize my lipolys over the last few weeks and have been amazed at how accurately the tool predicts the actual performance of my packs. It has been a huge eye-opener. Best of all it's really quick and I don't have to worry about damaging my packs by "testing" in my planes and possibly pulling excessive current. Bravo!

I hope to have the time to give back by filling out the spreadsheet and posting in the database in the next few weeks. Need to make some labels too!

G$
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Old Apr 17, 2012, 03:27 PM
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Originally Posted by gravityKills View Post
PS if you have to say something to somebody, why not say openly who you are addressing? Weasel words like "some" make at least me wonder, whether you are trying to dodge responsibility for your actions.
You are aware that such directness is considered a flaming remark and not tolerated; whereas an indirect borderline kindling flame (like Wayne calling me a b.g.t) is apparently permissible ... a fine line not unlike the fine IR line that you and I, and others find rather elusive and at times can confuse the average modeller as well as some relatively advanced hobbyists.

Quote:
The picture speaks a very clear language regarding the usefulness of IR as advocated here.
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Old Apr 17, 2012, 03:34 PM
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Originally Posted by gravityKills View Post
PS if you have to say something to somebody, why not say openly who you are addressing? Weasel words like "some" make at least me wonder, whether you are trying to dodge responsibility for your actions.
Ah, your grasp of archaic English is amazing viz, "weasel words." You just don't hear that phrase anymore....
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Old Apr 17, 2012, 03:34 PM
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Originally Posted by gravityKills View Post
PS if you have to say something to somebody, why not say openly who you are addressing? Weasel words like "some" make at least me wonder, whether you are trying to dodge responsibility for your actions.
you are right , so I corrected and addressed

Rob
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Old Apr 17, 2012, 03:37 PM
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Originally Posted by gbancrof View Post
I have been using the tool and one of my iCharger 306B's to categorize my lipolys over the last few weeks and have been amazed at how accurately the tool predicts the actual performance of my packs. It has been a huge eye-opener. Best of all it's really quick and I don't have to worry about damaging my packs by "testing" in my planes and possibly pulling excessive current. Bravo!
Yes, you can KIS. The average modeller doesn't really need and ESR or even have to determine the FOM to assess the actual predictability of questionable lottery packs from a Chinese distributor and thereby their usefulness. So, hope WJM will stop nit-pickin about such over-exacting calculations that they may find intriquing, but aren't necessary as so aptly expressed by gbancrof.

All you really need is a good balancing charger like the PL 8 or the i306B ... http://www.ultimaterc.com/forums/sho...d.php?t=124013
Quote:
this charger(i306b) works much like the imax, turnigy etc chargers...just with more options for everything...such as monitoring, cycling, internal resistance, foam cutter, and motor break in power
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Old Apr 17, 2012, 04:49 PM
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Originally Posted by JohnathanSwift View Post
Ah, your grasp of archaic English is amazing viz, "weasel words." You just don't hear that phrase anymore....

It's used in Wikipedia for "unsupported attribution" (WP:WEASEL).
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Old Apr 17, 2012, 06:10 PM
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I've got some wonderful Finnish friends here, and I'm always amazed at how well they speak idiomatic American english.

Actually, when I used the phrase years ago, it meant the tactical use of ambiguous words, i.e., words which, in conjunction with one another, destroy all meaning, purposefully. Lawyers are often said to use them.
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Old Apr 17, 2012, 07:00 PM
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Originally Posted by microwave View Post
Yes, you can KIS.
All you really need is a good balancing charger like the PL 8 or the i306B ...
I agree! That's what I used (iCharger 306B) to get IR and then plugged it in to the tool. Way easy and it proved to be surprisingly accurate after I got the chance to actually use it. No more guessing games or inflated C ratings for me.

Really grateful to those who contributed to develop, test, and publish the Lipo tool!

G$
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