I've been using Lithium batteries for my R/C plane, helicopter, and cars for a few years now. Each one of them (the batteries, and the charger for that matter) talks about how different the lithium batteries are from previous ni-cad type batteries. Heck, I have even had to retro fit my "toys" (as my wife put them) with lithium meters that show not only a charge level light, but also make an audible alarm when the juice is getting down to a dangerously low level.... Not empty, but just low. In older nickel based batteries, you just run them until they are dead. With lithium, you run them down to a certain point, and beyond that point you WILL permanently damage their ability to charge, and actually can "puff" the battery, which makes it risky for catching fire.
Anyway, draining too far is VERY bad.
Also, it explicitly states NOT to do the "drain and charge" business as it is no needed.
