If the wires to the charger are warm, that means they are really too small for the current being pulled. That warmth is dissipated power, which means the wire resistance and/or length is too high which creates a voltage drop, which means there is less voltage at the charger.
Yeah, I know that's what it came with, but I had that happen on my EOS7i too. I replaced the stock 6ft of wire with a 3 foot piece of 14 GA noodle wire and now the wire does not get warm and I have more voltage at the charger.
Here is the thread I started on this.