Nothing?  If im doing something wrong , could you advise.  Solar panel set up puts out 22 volt full sun, trickle charge, but want to make sure it stays under 14 volts to the battery and to camera. buck is red/ black to solar panel, yellow /black to battery, still getting hot on the case. So yellow and black hooked to battery and nothing else it gets hot, no panel installed.

I rather use it then return to amazon.

I have this solar panel..

https://www.amazon.com/gp/product/B003LZ4IK4/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

I ran the solar panel to the buck and then to the battery, nothing is hooked up to the battery yet,and it would get hot  .  Solar panel is not in the light at all (covered).  If the buck is connected to the battery and only the battery– yellow + and Black –  and nothing on the other end of the buck Red and Black wire, it gets hot, is it back feeding?

Take the buck, hook the output side yellow and black to a 12 volt battery and only that, should it get hot?  Do i need a one way diode or just something else? I used this set up two months ago and its perfect. same panel, battery and buck.