I don't use this app to often, usually only when I ride my motorcycle to work. So today, I unplug my fully charged phone and listen to the radio as I ride to work. I had it on for about an hour. After I quit the app I noticed that my battery icon was down almost half way. I checked out the status in Spare Parts and I was down to 64%! After just an hour of use!!!! I am glad that just on Friday I decided to bring a usb cable charger to work otherwise my phone would not have lasted the day today.