There are frequent heated discussions here on RCG and elsewhere on what the C ratings of LiPo batteries are, how they are obtained and how accurate they might, or might not, be ...
Here is an example of a so-called "LiPo C-Rating Calculator" that surprisingly does not even state what formula it uses to achieve the answer:
http://www.soko-heli-tools.com/en/li...alculator.html
One can even find a $90 device
that when plugged into your battery will give you your magic C-Rating:
https://hobbyking.com/en_us/wayne-gi...cell-lipo.html
It looks all like rather mysterious physics until you realize it is
all based on 1850's physics (Ohm's law) and middle school arithmetic (see below).
Here is some better discussion that leaves out all the foggy rubbish & nonsense (actually more of a sensible definition of terminology) :
http://web.mit.edu/evt/summary_batte...ifications.pdf
So what is the formula and what exactly does it tell you ??
So take the "calculator" from the first website:
A 5000mAh battery with a cell count of 6 and a cell IR of 2 milliOhm will give a C-rating of 24.5.
A little Mathematica algebra (see pdf below) allows to almost immediately extract the trivial (and ad hoc) formula they are using :
C Rating = 2451 / SquareRoot[ capacity * resistance ]
Nothing else enters the formula (try it out for yourself), all you need is the capacity in mAh printed on the pack (which most can read), and the
internal resistance (IR) in milliOhms.
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