I asked Bing Copilot: "Is a LIPO battery able to exceed it's "C" rating or, is that the upper limit."  Got a thorough answer that boils down to "Yes you can but you really don't want to".  Give it a shot, the AI's are slowly getting better.

From what I read in Bing's answer, we are really abusing our batteries.  The "Bing" calculator estimated that I could be pulling as much as 70 amps in a reverse wingover.  So why are my batteries only warm and my Spin 44 ESC acting normally after three years of abuse?  Obviously we do not pull that much.  So how much do we pull?  Bing's static watt figures matched what my 3520-810 pulls on the ground so I am curious why their "boost" figures were so high 35-50c in moderate maneuvers (do we have any of those) and as high as 70 in demanding maneuvers.  This is almost like say that I am flying 140' diameter circles on 55' lines. 

Is there a place I can go to see telemetry readouts from timers that support it to learn a bit more about the amp draw pattern as we fly the pattern?

Ken

I know the C rating is how fast the battery can safely discharge. Is the battery able to exceed that number or, is that the upper limit of what it CAN do?

If I push the load and the rpm way up will the battery be self limiting at the C rating or will it supply the extra power and burn up?

Thanks,
MM

Good question, I am actually writing an article about our equpment, here is part about it .... but to your question, no, the C rate is not self limiting and it is also not upper limit, you can always go higher .... on cost of battery life ... or to the point when electric converts to internal combustion 

so the part from article:

The C-rate is a convenient way to express discharge capability, but it is really just a reflection of internal resistance. In practice, manufacturers calculate the continuous C-rate from the cell’s internal resistance using a formula of the form:

C = 0.4 / ( Ri * capacity )

The constant 0.4 in the C-rate formula corresponds to an expected voltage drop of approximately 0.4 V across the cell’s internal resistance during discharge.

For example, a LiPo cell with 2700 mAh capacity and an internal resistance of 6 mΩ gives C=0.4/(0.006*2.7)≈25, which matches its 25C rating. Burst C-rates are often quoted even higher (25C-50C), but they simply represent short-term "burst" currents the cell can supply before heating and voltage sag become excessive. This calculation always applies to a single cell, for packs in series the C-rate stays the same.

I don't think most control line stunt guys will have good data for very hi drain situations.  You might look around other forums for the battery data for applications like racing quadcopters or other stuff that really draws high amps.  If the packaging (or rules allow), more voltage from a higher cell count cures many ills.

I data log many of my flights on my plane just for fun.  Here is a flight log from a few years ago using BA 2826/690, APC 12x6e, 6s2600 li-ion, FM-9 timer, Castle Edge-Lite 50 in Hi-Gov. 
Definitely not stressing out over the 20amps it pulls at max draw during the wingover and overheads. 

Thanks, it is comforting to see that we really do not pull that much in what you might call the Fox 35 setup of electrics.  The 3515 is a rough equivalent to the 2826 as to what planes it is appropriate for.  What was missing was the weight it was pulling, and the pattern would be quite different using the Fiorotti timer but probably not the extremes and still the numbers are nowhere near what the "Bing" answer suggested.  I would think that the ESC and Timer have survival limits that prevent them from asking for more amps than they can process, but that would be logical, and we do fly PA.

Ken

As Master Igor said, the "C" rating is another way of referring to the battery's internal resistance.

The big problem is that, when drawing high currents, the battery voltage will drop according to Ohm's law. The lower the C (and the higher internal resistance), the greater the voltage drop when the motor is under load during maneuver.

In simpler models and ESCs without a governor, the difference between a 30C and a 100C battery is dramatic.

In models with an ESC with governor and active timers, there won't be as much of a difference, but a high-C battery will run cooler than a low-C battery.

High-C batteries are heavier and more expensive.

Douglas

Technical stuff aside, I was always told by folks a lot smarter than me to stick with a "C" rating of 25 for our purposes.