I have a old iPhone 5s and it got dropped by one of my relatives. I grabbed my phone hoping it was not cracked but it would not turn on. I found out that if I plug the phone in it will start up and its says 53% battery left but when I unplug it, it turn off after about 30-50 seconds. My theory is that the battery is broke because it it was disconnected it would turn off immediately right? Please help, what do you think is wrong with it? Thanks!