Hi. I bought my second hand iPhone 5 about 3 weeks ago. It is on iOS 7.1.2 jailbroken. I installed Cydia tweak calle BatteryLife. It shows current battery capacity. Battery design is 1400 but my iPhone had sometimes about 700 sometimes about 500 and after a few days it showed 1100 of capacity. I bought new battery on ebay and replaced it by my self. At first it showed 1300 capacity. Few days later 600 capacity. Few days later 900 capacity and it statys now under 950. Can anyone tell me what can be the problem? My battery capacity changes very often it is very strange. At the moment i have 946 of capacity but 4 hours ago it was 1046 and yesterday it was 700.