Originally Posted by
TheZoof
Not true. C rating and Internal resistance are not the same thing. You will get a lower internal resistance with a higher C rating however C rating has nothing to do with the power the battery puts out. It is the value that the battery can handle before it CAN'T put out.
The internal resistance allows the battery to output higher voltage at a regular rate compared to nominal voltage. It would be like having a thicker guage wire. The motor is drawing the same current however the wire loses X amount during that draw. C rating would be like the same example except when the motor draws the current the wire can't handle the current and would melt or fail.
Hopefully that explains it. We are talking about a very small difference here and it is all on the assumption that a 90C battery is rated the identical way to a 50C battery.
Internal resistance was the number one value we looked at for matched batteries racing stock classes. It gave more power however drained your battery more so it wasn't as important in modified where run time was the most important.
The original discussion did not account for internal resistance. Just because a pack has a higher c rating does not mean it has a lower internal resistance. I was making the point about the c ratings (being the maximum that can be put out) if your system is not capable of pulling 40c then a 65c is going to give you the same run time. Now if you want to throw IR into the mix then sure. The same c rating packs with differing IR will produce different run times and power output. My only point was that c rating, by itself, has little to no impact on run time.
I wish more guys talked like you guys do. In my opinion the internal resistance is something that is more important than c rating. Thanks for the good discussion.