I have been flying my E7SE for several seasons now with no issues - a blast to fly. Last weekend, I lost a cell in the battery back. The helicopter obviously lost power (which was my clue to land), and I found one of the cells in the rear pack was at 0.12V. I chalked it up to bad luck, and accepted that the pack had close to 200 flights. I replaced the rear pack with a battery of like brand, size, and age. Today, I lost a cell in the front pack! Is this a total coincidence, or is there something going on? I don't really want to lose another pack! If you have any suggestions, please let me know.