Hi all. I just received my second P3 battery yesterday from CopterShop. I wanted to ask for some opinions on the best way to manage a second battery. Typically I only use one battery. Do you keep your 2nd battery fully charged at all times so its ready to go should you decide you want to fly the P3 longer than 20+ mins on the first battery? I know after 6 or 7 days the battery will discharge about 10% right? or Do you just alternate between batteries (Leaving one partially charged) so there's equal use and only charge both batteries full if you know you're going somewhere that requires more flight time than 20+mins? Thanks!