Water damaged Iphone 4s only works when plugged in to charger?

So, I have a water damaged iphone 4s that works perfectly fine, except for the fact that it only turns on when it is connected to a power outlet. The screen works fine when connected and I can access menus and videos and such, but when I unplug it, it immediately turns off. I already changed the battery from another iphone to this one, but it still does the same thing. Anyone know what to do?

Theirs nothing you can do but hopefully be able to get new one I had same problem and mine eventually didn't even work that way any more after couple of weeks

If its water damaged then you will have to have someone look at it. I don't think there's an unwaterdamage app.