Pelts are really inefficent. They generate nearly as much heat as they transfer, so putting 2 pelts together just generates tonnes of excess heat. The coment about the second pelt needing to be twice as powerfull as the first one is true. If the first pelt is pumping say 150 watts, and generating 150 watts, well then the second pelt has to pump 300 watts, which means it would also create 300 watts, and all of the sudden your poor heasdink is trying to deal with 600 watts of heat. These numbers arn't compleatly accurate, but they give the idea. Finding a pelt big enough to deal with the heat load form the first pelt is a problem too, since you still need a decent sized pelt on the CPU (ie 200 watts or so)