[outworlder]

Not sure if the 99% figure is correct, but it is certainly above 80%. Electric motors run quite cold compared to motors that are burning things. Cooling is unlikely to matter.

Now, wouldn't the cold air at higher altitudes present a much bigger problem for the battery? FL20 and up you can easily reach temperatures where current batteries are no longer usable.

[YUMad]

90% is the usual assumption.