I had problems with the battery phantom vision + 2 . I have 2 sets of batteries . Each battery is marked with a " 1 battery " and " battery 2 " . both full battery charge . but I only use only the battery 1 and battery 2 is not used since I bought it in October 2014 , but in the last 2 weeks I have been using the battery 2. before flying , I have checked the battery and it is still full . after flying approximately 50 seconds, the indicator Bate in the DJI Apps produce alarm and show my battery is already in 45 % . green light on the plane turns red and blinks and suddently my plane getting slow and landed itself . why it happened. please help me ......

p/s- sorry becaused my english verry poor

It is not good to story the battery fully charged for a long time.  You should review the phantom_2_vision_plus/Smart_Flight_Battery_Safety_Guidelines.pdf

thanks for your advise