Pandora, Maps & Battery Drain

I use my phone as a GPS and at the same time run Pandora through my car's speakers. I am connected to a USB port in my car. I have done this for many years. Recently I have noticed that when doing this my battery drains significantly when at best it should be charging and at worst keeping the same charge level. I can run either app by itself and the phone charges. Is this a sign that my battery is going?