Just had my first battery problem. I had around 7 min of fly time left and the battery went all the way down to 7% like a rock. Luckily, I saw that it was dropping and landed it. I got back home and the Phantom Assistant Software. I'm afraid to fly it now with this problem. I have anther battery however I wonder if it will do the same thing? It's still under warranty, bought it at US Hobby. Any suggestions?