My 1994 NSX had something happen to it that I have never seen before. I washed my car and noticed smoke coming from the positive battery terminal. I quickly removed the spare tire, and wiped all water away from the terminals. Upon inspection, I noticed there was a lot of corrosion around both battery terminals. Taking a 10 mm socket I loosened the nut on the negative terminal and removed the cable from the post. When I attempted to do the same to the positive terminal, I noticed that the 10 mm wrench was suddenly too big. It appears that the nut had corroded to a smaller size. Finally I was able to get a 3/8 socket to fit on it, but it would not turn. The bolt was not moving, so I sprayed it with penetrant and let it sit for a while. After that I then attempted to loosen the nut and to my shock the nut did not move and the circular end of the positive cable separated!! I was in shock! So now the positive terminal does not have a completed circular end, as it is 3/4 of the way separated. How does this happen? Also, how hard is this to fix? The dealership says the part is about $140, and the labor is about $240. Any help, or experiences with this is appreciated. I want to know why it happened to that I can prevent it in the future, and know how involved replacement is if I can do it myself. Thank you.