Thread Tools
Sep 20, 2019, 06:23 PM
Registered User
Quote:
Originally Posted by nuts-n-volts
As a subscriber... Your posts don't make sense. You have not given any facts or analysis. You simply state! Sorry dude, but your C rating is about dead. Post some data and some facts and maybe I'll give you another read.
Correct. I simply stated a few simple observations not anticipating so much agitation and anger from the "gurus" in the thread. Apparently people are too narrow minded to take any different opinion. I will try to take some photos when I am home and to back up the claim for sure.
Sign up now
to remove ads between posts
Sep 20, 2019, 06:25 PM
Registered User
Quote:
Originally Posted by Ohmic
So what exactly does your $40 reaktor say?
??? my point is a $40 charger can measure IR. And if you had to do a full discharge to be conclusive then whats the value of just measuring the IR.
Sep 20, 2019, 06:33 PM
aka JetMan Joe
MCSGUY's Avatar
Thread OP
Quote:
Originally Posted by vincesd
I read your post in a haste and missed this paragraph. If you are so narrow minded as to viewing anyone questioning with your theory as taking shots at you, then I'm not taking pot shot from sideline. Instead I'm standing in the center and taking headshots.

And how does flying more expensive planes than $200 foamy has anything to do a factual debate that IR resistance is reliable or not? Are you trying to show case that you are wealthy enough to afford planes over $200. I'm quite impressed.
Actually I don't believe you were taking shots at me. I understood you to be criticizing IR methodology and I appreciate the work the guys who developed and support it have done. They've helped our sport considerably.

Yeah, the foamy comment was a cheap shot, I apologize. However I stand by my other comments and head shots or pot shots yours don't reflect well on you.

Joe
Sep 20, 2019, 06:40 PM
Registered User
One thing you got it wrong. I am not criticizing. I am questioning. As in I have observation that contradicts it. Anyway, as you and other stated, its pointless to argue. Let me take some photos over the weekend and present what I've seen for all to analyze.

Quote:
Originally Posted by MCSGUY
Actually I don't believe you were taking shots at me. I understood you to be criticizing IR methodology and I appreciate the work the guys who developed and support it have done. They've helped our sport considerably.

Yeah, the foamy comment was a cheap shot, I apologize. However I stand by my other comments and head shots or pot shots yours don't reflect well on you.

Joe
Sep 20, 2019, 07:31 PM
Registered User
Me thinks this convo isn't going to yield much fruit. Some (myself included) find great value in IR testing. Others, not so much. To each his own.

Time to shift the focus of this particular thread back to Joe's testing?

Mark
Sep 20, 2019, 07:36 PM
The 6 P principle works for me
elecfryer's Avatar
Vince, it is easy to criticize and important to understand what one is talking about. Given what you are writing, I don't believe you have read the entire thread (many, including me - have read it) and since you have not stated some facts, you may want t to do some more research.
Not all chargers give the same "IR" results and some are way off. Of course if you run all your batteries thru the same charger then you can normalize the results.
You make no note about the temperature at which you took the IR readings. This is one of the missing facts and is relevant.
Just a couple of things to think about.
I am happy that Joe started this thread and is continuing with his experiments.

Michael
Sep 20, 2019, 08:26 PM
Registered User
Quote:
Originally Posted by vincesd
??? my point is a $40 charger can measure IR. And if you had to do a full discharge to be conclusive then whats the value of just measuring the IR.
If your $40 charger does everything you need you're set.
Sep 20, 2019, 08:47 PM
aka JetMan Joe
MCSGUY's Avatar
Thread OP
Quote:
Originally Posted by mrforsyth
Time to shift the focus of this particular thread back to Joe's testing?
Mark
In that vein I just ordered a 6S 2200 Rhino to baseline the GN3 6S 2200 Flight pack against. We know the Rhino is a true 50C unit so it will provide a good frame of reference for the test.

Joe
Sep 20, 2019, 08:57 PM
Registered User
atreis's Avatar
On your testing of smaller packs:
Quote:
Originally Posted by MCSGUY
... You guys that test small graphene packs, do you generally see relatively low temperatures after a run at maximum C levels?
I don't test like you do, but can say that after a 2-3 minute run in a smaller EDF (4s 64mm 12 blade for instance) they come down quite warm to the touch, same as a similar run in a larger EDF plane that drains a 6s 5000 pack in 2-3 minutes. I'd naively expect you to see similar heating in your testing as you see with the 5000 packs ...

BTW - My EDFs are almost all foamies ... Freewing does a nice job.
Sep 20, 2019, 09:10 PM
Registered User
Does this website have an ignore feature?
Sep 20, 2019, 09:36 PM
aka JetMan Joe
MCSGUY's Avatar
Thread OP
Quote:
Originally Posted by atreis
On your testing of smaller packs:

I don't test like you do, but can say that after a 2-3 minute run in a smaller EDF (4s 64mm 12 blade for instance) they come down quite warm to the touch, same as a similar run in a larger EDF plane that drains a 6s 5000 pack in 2-3 minutes. I'd naively expect you to see similar heating in your testing as you see with the 5000 packs ...

BTW - My EDFs are almost all foamies ... Freewing does a nice job.
I'm a recent convert, just ordered my second Avanti. It and my EFX are actually the planes I fly the most. Lee and I chase each other's EFX around our field like a couple of angry bee's. 4S overcharged Panthers and 7x7 Aeronauts get us to about 135mph and we try staying within a 300' x 150' oval at about the same height. I figure the safest way to fly close is to try crashing into each other, it'll never happen that way . About the most fun I've ever had with foam that didn't also involve beer

Joe
Last edited by MCSGUY; Sep 20, 2019 at 09:42 PM.
Sep 20, 2019, 09:38 PM
ancora imparo
jj604's Avatar

Temperature rise of smaller packs at high rates


Joe, here are the results of some constant current load tests I did on 4S 1300mAh packs at 40C, 54C, and 60C rates. The average cell voltage is plotted on the Y axis against discharge time on the X axis.

The surface temperature rise is marked on the 40C and 60C curves.
Personally, I take a 50C rise as the absolute maximum allowable to accept that particular C rate (as well as other criteria like voltage drop of course). A 50C rise corresponds to a maximum temperature of 70C at a standard 20C ambient. This value of 70C maximum temperature has been recommended by a number of vendors. It is very hot but the Graphene formulations seem to cope with it. I am sure the cumulative degradation of the cell is high at these temperatures, but the Graphene type packs don't puff at this value.

None of these packs exceeded that 50C rise even when grossly overstressed at 60C rate. At 60C both the Graphene and Panther are showing significant voltage dip and recovery and the mid discharge voltage is below 3.5V/cell. They are clearly not 60C rate capable packs. The maximum temperature rise was however only 49C. This occurs well after the load is removed as the surface temperature of the pack continues to rise for a minute or more.

We have speculated that the smaller packs do better thermally because of the larger surface/volume ratio over larger packs. Internal heat generation is assumed to be a function of volume at any particular current, cooling is a function of surface area. Measurements I have made of internal LiPo temperatures however suggest that surface cooling is largely irrelevant at extremely high constant current rates where discharge occurs in about a minute. Temperature rises uniformly at a linear rate throughout the pack.

Conclusion: Smaller packs do a bit better thermally but at high rates the difference is fairly small.
Sep 20, 2019, 09:58 PM
aka JetMan Joe
MCSGUY's Avatar
Thread OP
Excellent information John. So not seeing the temp rise I'm used to on the surface probe is to be expected (somewhat). That makes me feel more on top of the testing again, Thanks!

This also got me thinking on how much the excessive power lead and termination temperature propagates through the pack. 50C for 2200's is no stress whereas 50C with 5000's runs very close (in all cases without Dinogy style festooning headers) to melting the solder. IMO it's another reason Jim's idea to release the XPS with 8 awg leads is a good one, especially for the big stuff.

Joe
Last edited by MCSGUY; Sep 20, 2019 at 10:09 PM.
Sep 20, 2019, 10:08 PM
Which one is aileron again?
Maybe I missed it but what is this "GN3" battery? Is this another brand from Hobbyking?
Sep 20, 2019, 10:16 PM
aka JetMan Joe
MCSGUY's Avatar
Thread OP
GaoNeng, relatively new on the scene is generating some positive buzz in the smaller pack arena. A 6S/2200 is the largest pack that's available. Their website shows a larger option but it apparently hasn't been released in the wild yet.

Joe


Quick Reply
Message:

Thread Tools