I purchased a CanaKit like the one in this link and I correctly wired it to a 12VDC and did not wire any load to it. As soon as I turn the power on it gets quite hot that it is almost melting. After the first time I tried a few more times but for a second or two just to measure the output at M- and M+ without load and got almost 0 volts. Any ideas what I'm doing wrong?