Originally Posted by Andy from Sandy
If I have a motor / ESC combo that requires 50 Amps for example but the IR of the pack wouldn't allow that much current to flow what is the effect on the LiPo?
Current draw is determined by motor, prop, and battery voltage. If the motor/prop combination is trying to draw current in excess of the battery's ability to safely source that amount of current, the net result will be overheating and early demise of the battery.
To use the spreadsheet, plug in the highest measured cell value and it will calculate the maximum safe continuous current for your pack. Next, measure current draw on your power system at full throttle with the same pack to ensure that it is no greater than that recommended by the formula. As long as you're in the ballpark you'll be ok. If actual current draw is far in excess of that recommended by the formula, it's wisest to get a better battery or use a smaller prop.