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Old Nov 19, 2012, 10:13 AM
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Originally Posted by Prof100 View Post
I am not surprised, just disappointed in lipo makers not supporting a reasonable way of judging the quality of their cells.
Some are, but most understandably will not. Progressiverc.com has started quoting measured performance data on their Spyder packs, which I find exceptionally commendable.

Many other vendors hide behind ridiculous 'C' ratings that most modelers have no way of verifying. The 'C' rating is their snake oil that helps them sell packs. Put a higher number on the label, charge more $$, vendor wins. This ridiculousness is the primary motivation behind the Lipoly Performance Database. Having performance data in one place that can be easily verified by the modeler levels the playing field significantly and separates wheat from chaff.

I added the poll to the Database thread a few months back to see if folks felt it was helpful and am encouraged that many do. There are a few who have also registered their displeasure that objective data is being compiled. Perhaps they've something to hide?

Cheers,
Mark
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Old Nov 19, 2012, 10:19 AM
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Originally Posted by mrforsyth View Post
There are a few who have also registered their displeasure that objective data is being compiled. Perhaps they've something to hide?

Cheers,
Mark
Were those independent individuals, field reps, or vendors who voiced their displeasure?
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Old Nov 19, 2012, 10:33 AM
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I wanna see some tests on the thunderpower line of batteries!
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Old Nov 19, 2012, 10:43 AM
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Originally Posted by Ohmic View Post
Were those independent individuals, field reps, or vendors who voiced their displeasure?
Hard to say for sure. Just might be a combination of the above. Some may even be glow or glider folks who have little to no interest in lipolys.

Mark
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Old Nov 19, 2012, 10:55 AM
Shut up and fly
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i would like to say this info has help me a bunch. i bought some used battery from here, he included his IR reading even though they look ruff the readings turned out to be true got a great deal on some good packs of batterys
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Old Nov 25, 2012, 04:24 PM
ago involo ergo sum
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Originally Posted by keithy4129 View Post
I wanna see some tests on the thunderpower line of batteries!
I used Wayne Giles 1st gen ESR on some of my TP packs and the results were underwhelmingly discouraging. I haven't gotten around to posting the results yet and I'm working in Germany for another week but will share 1st week of Dec ( if not distracted by other things)
It convinced me not to buy any more. . . . .
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Old Nov 25, 2012, 06:31 PM
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Originally Posted by MikeAnderson View Post
I used Wayne Giles 1st gen ESR on some of my TP packs and the results were underwhelmingly discouraging. I haven't gotten around to posting the results yet and I'm working in Germany for another week but will share 1st week of Dec ( if not distracted by other things)
It convinced me not to buy any more. . . . .
thats what i figured, what c-rating do you have? the prices they charge are outragous, I dont know how they stay in business, I personally don't know anyone who uses their packs, I thought about buying some of their smaller packs to see how they are.
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Old Nov 25, 2012, 06:31 PM
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Remember all packs will be significantly worse than advertised, not just tp. If you were happy with them before why should a number change your satisfaction?


Quote:
Originally Posted by MikeAnderson View Post
I used Wayne Giles 1st gen ESR on some of my TP packs and the results were underwhelmingly discouraging. .
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Old Nov 25, 2012, 06:34 PM
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Originally Posted by biskit View Post
Remember all packs will be significantly worse than advertised, not just tp. If you were happy with them before why should a number change your satisfaction?
perhaps so, but the amount of money they charge is ridiculous, thanks to this meter we can get better packs for a third of the price.
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Old Nov 25, 2012, 10:56 PM
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is this tester valid on life batterys too
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Old Nov 26, 2012, 02:23 PM
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Papabatman: yes. Battery chemistry does not matter. There is a low voltage limit but I don't know what it is, perhaps Wayne can tell us?
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Old Nov 26, 2012, 02:56 PM
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i figured it out life is more about volts then amps
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Old Nov 26, 2012, 03:41 PM
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Originally Posted by biskit View Post
Papabatman: yes. Battery chemistry does not matter. There is a low voltage limit but I don't know what it is, perhaps Wayne can tell us?
The unit uses the battery under test to power its own electronics so that any pack of under 6V ON LOAD will not give a valid reading unless the single cell modification has been carried out. This enables the unit to be powered by a separate source such as a 2S or 3S lipo via an auxilliary input lead.
Under these conditions it will measure the IR of a single cell of any chemistry with a cell voltage of between 1.5V and 4.5V.

So in practical terms this means that you can measure an LiFe pack of between 3S and 7S without any modification and down to 1S with the single cell mod.

The minimum of 1.5V means you cannot measure a single NiCad or NiMh cell but you can always measure two in series and halve the value! ( Assuming they are equal of course)

Wayne
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Old Dec 03, 2012, 01:26 PM
ago involo ergo sum
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Kemptville, Ontario, Canada
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Originally Posted by MikeAnderson View Post
I used Wayne Giles 1st gen ESR on some of my TP packs and the results were underwhelmingly discouraging. I haven't gotten around to posting the results yet and I'm working in Germany for another week but will share 1st week of Dec ( if not distracted by other things)
It convinced me not to buy any more. . . . .
Pack 1: TP 3800 ProPower 45C 6S purchased from DraganFly: Worst cell IR=4.92. Calculated C-rating =18

Pack 2: Turnigy "Blue" 3600 30C 6S purchased from HobbyKing: Worst cell IR=4.16. Calculated C-rating=20.

In fact one of the two 6S Turnigy packs had a dead cell on arrival, so I paid a LOT for the one surviving pack. But to see that the TP pack is no better is discouraging.

These are used in an EDF that pulls no more than 80A but flies most of the flight at part throttle - say 50 A. So they are both seeing less than the calculated max amps and both should last as long.



I don't seem to have good luck with selecting "good" LiPos.
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Old Dec 03, 2012, 02:32 PM
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Originally Posted by MikeAnderson View Post
Pack 1: TP 3800 ProPower 45C 6S purchased from DraganFly: Worst cell IR=4.92. Calculated C-rating =18

Pack 2: Turnigy "Blue" 3600 30C 6S purchased from HobbyKing: Worst cell IR=4.16. Calculated C-rating=20.

In fact one of the two 6S Turnigy packs had a dead cell on arrival, so I paid a LOT for the one surviving pack. But to see that the TP pack is no better is discouraging.

These are used in an EDF that pulls no more than 80A but flies most of the flight at part throttle - say 50 A. So they are both seeing less than the calculated max amps and both should last as long.



I don't seem to have good luck with selecting "good" LiPos.
Mike,

Those figures do look higher than I would have expected, but not dramatically so.
Are you measuring at 22degC and leaving the packs in that ambient temperature to settle for at least an hour ( preferably more) ?
Also how old are these packs?

It just demonstrates the lottery there is in buying lipos. I have had some Turnigy Blue which are really good; a 2200 25C pack with Cell IRs of mid 4s and some 5000 25C packs all showing cell IRs of just over 2milliohms suggesting that the C rating is near enough genuine. I have done several full rating 25C test discharges on the smaller pack and flown it a fair amount and it is still fine after about 3 years. On the other hand I have had some poor Turnigy blues and even worse Nanotechs; either they change suppliers or have poor quality control.

I don't think you are alone in your findings.

Wayne
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