I have a P1 that I bought second hand. He included the original gray Phantom battery, which I don't use, and then a pair of better batteries. (I can't remember the brand, they are at home, and I am at work) Long story short, I don't know how he treated them before I got them. When my battery reads around 10.8 on telemetry on FPV, I bring her on back down. Yesterday the wind began to come in, so I came down sooner, around 11.4. When I pulled the battery out, it was puffy on the sides. (it now has a big red X on it and will be disposed of properly) The advice I need is this. What pair of batteries should I get? I will get two pair, and run dual batteries. Also, when I get them, should I do a priming procedure of some kind? And as far as properly discharging them, what do you guys suggest to give them the best care, and longevity?