Me personally..... I would not take a chance with ANY battery pack.... even if it is new. I would wait and cycle the battery at least 3 times. You would be surprised on how many batteries (even new ones weather Nimh, Nicad, etc...) need to be cycled before being put into use. If anything.... it is insurance to prove the pack is good (no bad cells) and can perform to the needs of your flight pack. Bottom line is this. If you want to take a chance with your plane over a 2nd hand battery (even if new) with out you knowing the history or "true" capacity of the cells themselves.... go for it. Sure, the odds are in your favor..... but that would be like buying this plane, put the wing on it and fly it before looking/checking things over to make sure everything is up to snuff. Not to be harsh here... just hate to see another plane go south over a battery pack. I have done it myself and learned the hard way.