Chescold fridge/freezer

A warning and a question. I own a Chescold 3 way fridge/ freezer of which up till now I couldn't fault. During a recent trip the inside of the chest developed a foul smell which no amount of cleaning could get rid of. On getting home and cleaning it properly, a crack was discovered in the bottom corner and the juices of all sorts of things had entered causing the smell. I plan to seal it and hopefully trap the smell in. If you own one of these fridges - keep an eye out for this type of this thing!
Now for the question. I run this fridge in the back of my 80 series and have 2 very large cables (1x pos and 1x neg) running from the large aux' battery down to a 2 pin 15 amp plug in the back. After about an hours drive the plug and wires into the fridge get too hot to touch (the heavy cables do not - as you would expect). Why are the fridge's cables getting so hot? Is there something wrong with the fridge? For the cables to be getting so hot, the fridge must be drawing too many amps so why has Chescold fitted too large an element or too small wiring. Any professional help would be greatly appreciated before an emergency arises. Thanks guys.