Oof…classic power cell (LA) vs. energy cell (50E) comparison, showing how capacity should be close to the last thing we consider when choosing a cell.
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A lot of the battery tests use constant discharge rates, but in esk8 the load varies all the time. How would a energy cell like the 50E perform if it was pulsed to 20A for a few seconds, then allowed to cool down at like 5A for a few minutes. Aside from lots of sag, does this cause significant damage to the cell?
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It would perform like crap, huge voltage sag, and there would be accelerated aging of the cell from running it that hard.
When “pulsed” the outside cell temp is misleading. Inside there can be hotspots where current concentrates at verrrry high temps. That’s where the cell will be damaged. But by the time the heat from those hotspots spreads out and reaches the outside of the cell there can be very little temp increase.
Basically, a low power cell will always be a low power cell. 
There is no way to make it suitable for high power use. No matter what you will get significant voltage sag and/or damage and aging of the cell.
There’s no way to quantify the level of damage without tons of testing. But the higher the current level, the longer the high current pulse lasts, and the more often that is done the more the cell is damaged.
An occasional pulse wouldn’t make any measurable difference in cycle life (you will always see the voltage sag though, every time). But as the level, length, and frequency of the pulses increase the damage will be noticeable sooner and sooner and be worse and worse.
There is no way to avoid aging of the cell. All we can do is try to minimize it by running it conservatively (if cycle life is a priority). If performance is a priority then running a cell at anything above about 75% of its rating is not good.
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