Nice experiment man! Don't forget to write down the results you get for yourself and for public knowledge as well 
Specifications usually mention 0 deg C as a minimum, because equipment is not tested below that, but this doesn't mean it won't work. Maybe you can even give feedback to the manufacturer saying that you tested it for X time and worked / did not work.
As for your cables, others said as well, look into them. Burned cables are no good. Also, 4A/mm2 can be taken as the rough measure on how much current you can push through a copper cable. Don't go above it when operating continuously.
Specifications usually mention 0 deg C as a minimum, because equipment is not tested below that, but this doesn't mean it won't work. Maybe you can even give feedback to the manufacturer saying that you tested it for X time and worked / did not work.
As for your cables, others said as well, look into them. Burned cables are no good. Also, 4A/mm2 can be taken as the rough measure on how much current you can push through a copper cable. Don't go above it when operating continuously.
Cables are not that expensive they really need replaced with proper cables. It appears like it burnt through coating on parts and is covered with electrical tape. Just almost asking for electrical fire with that.
You will think us one day if you spend the money to get new wires.
Yes, I agree. Even if they are working ok now as OP says it's still better replace them because electrical tape is not a good coating for cables.
It honestly hurts me to read threads like this. Those wires are not safe. Add some cold weather and some snow/other water source. Combined with exposed wire... it's asking for trouble.
I can understand trying to stay low cost but really change out the wires. After you burn them out electrical tape is not a fix.