I've searched threads but none of the questions were exactly like this one. I realized my cheapie am/fm radio was irritating me with its tinny speakers. I have an old iPhone 3s that is no longer working as a phone, but I still use it as an iPod for general browsing, email etc. It occurred to me I could use it as my radio along with a little plug in speaker that has much better sound than the old radio. But, leaving the phone on all day streaming my fave radio station I assume would drain the batter really quickly. So, my question. Can I leave the iPhone/speaker setup permanently plugged into the wall. I'm concerned by how much the plug heats up while it's charging the phone. Maybe it isn't build for such continuous use. Opinions?