Reading earlier you said the heat caused resistance it's the other way around the resistance caused the heat. Without the resistance there would be no heat so where there is heat address that part. If all you have are bolt on terminals and there is heat there make sure it's clean thing another thing you can do is get come copper anti cease (it's like the gray stuff but it uses copper.) Make sure the post to battery are clean well mated.
Remember that all the wires electrical parts have been engineered if there are problems in the engineering it would be widely addressed here. So If you find any kind of burnt wires or heat address them. I am a little confused what are the problems that your still having.