I think he is referring to letting the cells cool. But, what doofus brings only one pack?? Li-PO or even some good IB3800's or 4300's. Run time and power to boot. And speaking of running, suppose the weather changes? With nitro, you have to re-tune, avoid the flame-out yada yada. Electric is more fun. Nitro has its advantages, I own a couple. Look for a nice shootout in the next couple of months in the mags. With the way LI "everything" (PO, MN, ION) is going, nitro is in trouble.