If you meet abnormal battery capacity, like sudden drop or short battery life etc. it is not the quality issue. Please charge the watch more 2hrs before you start to use it. And use the watch till battery empty and charge it up to full for 1-3cycles, the battery capacity indicator will be on right status. Please feel free to contact our Mobvoi Support Team on Official Website, we ll reply your email whithin 12 hours. Please kindly be noted that: Do not put the watch into fire or expose it to heat of 104℉ or greater. Do not expose the watch to -4 ℉ or lower temperature. Do not try to take the watch apart or modify it. Do not expose the watch to strong impact or shock.