As others on their board, I'm having issues with the 4s battery life. As a test, I want to drain the battery completely and then see how it reacts after a full charge. I've yet to bring it down all the way as I constantly need it on weekdays for phone calls. What is the best way to quickly drain it? I do not have videos or music on it (it is a business phone) so having it play something endlessly does not seem like an option. Is there a particular app or something which I can set it at and then leave it alone to drain?