Wirelessly posted (Mozilla/5.0 (iPad; CPU OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A334 Safari/7534.48.3) I have had terrible battery life on my iPhone 4s. Last night went from 100% to 66% while I was asleep and getting ready for work in the morning. Usage showed over 9 hours since last charge but showed usage of 9 hours. During that time I had not touched the phone. What causes usage in background while phone is locked? Something is wrong not sure what. Have drained the battery and recharged no help. I had a iPhone 4 with ios 5 with all the same settings and things running and did not have this problem. Ps if you phone works and battery is good don't post on this thread. I'm glad for you. We are all glad for you. Mine does not!