You have mixed up your wiring IMO. I disagree with above idea that your solar set is junk, just because you can buy better ones.
Your panel when disconnected and aimed at the sun will have around 20v at the pigtails
If you connect the controller to the battery and then the controller to the panel aimed at the sun, you will now see battery voltage 13-15 whatever it is at the time at the panel and at the controller "input".
Your situation appears to be that the controller is on the panel and not the battery. You might even have the panel wired into the "battery" connections instead of the "array" connections. Do not use the "load" connections at all (if any in that controller)