The above comments are correct. Memory is essentially a myth brought about by erroneous data gathered back in the first spacecraft days ( I was part of that and spent many hours unsuccesfully trying to prove/disprove the memory myth) where it was quite soundly proven that there is no such thing as NiCad memory. There is some side effects that led to this missinformation but they are quite complex and lengthy explanations. Suffice to say, don't worry about memory. Just charge at .1C (what your wall wart that came with your system puts out overnight before you fly, whether or not you have used the battery, you won't damage it a bit and will be assured of a full charge.