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Old Jan 11, 2013, 04:56 PM
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Australia, VIC, Melbourne
Joined Nov 2006
11,267 Posts
Huh? IR goes up... volts over the battery go up, so volts on motor should drop... thus Amps/Watts would fall too.... not go up.
It would be handy to see a logger, so it charts them all.

I have never encountered that case....... but maybe the motor gets HOT, its impedance goes DOWN for some reason, thus Amps increase (even for the same volts) and it burns more and more power for nothing (because it all goes in heat).
As a possible explanation if the battery is known to be fine to cope (eg that 65C rating).
The IR500 motor might be "pretty good" but not truly "good enough" for its application.
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Old Jan 11, 2013, 06:09 PM
C.E.R.N. field tester
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United States, NE
Joined Sep 2012
1,032 Posts
"but maybe the motor gets HOT, its impedance goes DOWN for some reason, thus Amps increase (even for the same volts) and it burns more and more power for nothing (because it all goes in heat"

I don't believe the impedance will go DOWN on any motor that is getting hot. The impedance will rise with temp. I do agree that it is running inefficiently at WOT on 5s. Will test again with a 4s lipo tomorrow. At this point I still plan on using this setup in the habu on 5s, just limiting wot to short bursts. I knew it was going to be a "hot" setup when I ordered it, looks like 1/2 to 3/4 throttle for safe flying.
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Last edited by supercollider; Jan 11, 2013 at 07:44 PM.
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Old Jan 11, 2013, 06:25 PM
chuck
santa barbara, CA
Joined May 2009
4,182 Posts
ya , known fact, ir rises in copper w/ heat . if u can find something to wind these things w/ that works the other way let us know

chuck.
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Old Jan 11, 2013, 07:24 PM
Life begins at transition
Australia, VIC, Sale
Joined May 2007
3,593 Posts
The IR of the battery goes *down* as it heats up. The resistance of the copper goes up, but the reactivity of the chemistry goes up by a higher amount. Hence the total voltage goes up.

Ever found your batteries are weak as p!ss in winter for the first lap or two? That's why.
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Old Jan 11, 2013, 07:37 PM
Gorilla Glue Expert
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United States, PA, Doylestown
Joined Sep 2010
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Quote:
Originally Posted by chas650r View Post
ya , known fact, ir rises in copper w/ heat . if u can find something to wind these things w/ that works the other way let us know

chuck.
Gold. All you gotta do is get some 20 ga. solid gold wire. Be the best motor you ever had.
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Old Jan 11, 2013, 08:19 PM
chuck
santa barbara, CA
Joined May 2009
4,182 Posts
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Originally Posted by PikeStaff View Post
Gold. All you gotta do is get some 20 ga. solid gold wire. Be the best motor you ever had.
i knew that was coming
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Old Jan 11, 2013, 08:50 PM
C.E.R.N. field tester
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United States, NE
Joined Sep 2012
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Quote:
Originally Posted by PikeStaff View Post
Gold. All you gotta do is get some 20 ga. solid gold wire. Be the best motor you ever had.
Ha! You want to go havsies on a spool?
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Old Jan 11, 2013, 09:22 PM
Registered User
Joined Jan 2013
4 Posts
Hello friends,
I want to use Turnigy sk3 3300kv on this blade w/ turnigy A spec 1300mAh 45C/90C and i'm going to use it around 10 seconds only
my question is, how much thrust will i get ? And will the battery stand for 10 seconds at full thrust ?
And, is there any recomendation to maximize its power ? Because i need maximum thrust for only 10 seconds.
Thank you
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Old Jan 11, 2013, 09:25 PM
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Question..Has any one used HK Rhino packs , say a 2350 @30C for a 6s set up. CP 2200 motor.
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Old Jan 11, 2013, 10:52 PM
chuck
santa barbara, CA
Joined May 2009
4,182 Posts
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Originally Posted by 91-ZULU View Post
Question..Has any one used HK Rhino packs , say a 2350 @30C for a 6s set up. CP 2200 motor.
all of the rhino's i have ever owned have proven to be some of the best i have had. no experience w/ the 6 cells though.

chuck.
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Old Jan 11, 2013, 11:39 PM
It should fly at least once
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Australia, NSW, Grenfell
Joined Mar 2006
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+1 on the Rhino's
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Old Jan 11, 2013, 11:56 PM
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Greece, Attica, Athens
Joined May 2011
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Quote:
Originally Posted by 91-ZULU View Post
Question..Has any one used HK Rhino packs , say a 2350 @30C for a 6s set up. CP 2200 motor.
Rhino packs are pretty good but 2350mah is a touch small.

It will not be able to deliver the 70+ amps required.
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Old Jan 12, 2013, 02:37 AM
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Ok so 4k it will be.
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Old Jan 12, 2013, 02:47 AM
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Greece, Attica, Athens
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Ok so 4k it will be.
4000mah?

If you can fit it in your plane and achieve a proper cg then yes. Otherwise 2700-3000mah as a minimum.
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Old Jan 12, 2013, 10:20 AM
scunna
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United Kingdom, England, South Shields
Joined May 2007
599 Posts
Hi guys, been extending my loft so i have more room. Most of them have 70 and 90 mm changesun fans fitted

My jets (1 min 6 sec)
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