Dualshock 4 (older model) charges but won't stay connected to the console.

Not sure what to do at this point other than buy a new controller.

It's currently charging but it shows that it has a full battery. Most of the time it won't connect at all (even when connected via USB), but when I can get it to turn on it will stay on for around 15 seconds and then disconnect. When it is on it has random phantom pushes of the home button.

I have reset the controller multiple times.

Really want to finish the raid on D2 tonight but I don't know if I can fix or have a new controller by then. Suggestions please??