I bought an AC charger that's advertised as 3 Amp. (It's the PowerGen dual-port USB charger that's received good user ratings on Amazon.) I'm using it now, but it's been charging much slower than my old 1-Amp charger. My phone is slowly losing charge when it's charging and being used at the same time, (with my old charger, my phone still gained charge when I was charging and using the phone at the same time.) Is the an app that can show how much my phone is charging?