This is something I did for my o/t daily driver. I replaced my battery tray with a new one, you can see where it was an improvement over the lacey-looking thing it replaced. There was obviously some corrosion on the bolts that held in the old tray, and naturally there was that one bolt that would not come out. So that stopped me cold until I got this Topec Impact Bolt & Nut Remover Set 13 Pieces from Amazon. They worked like a charm,if you don’t have a set like this, you are missing out. I had put some PB Blaster on the bolt in question and let it soak, the bolt head was corroded enough that I could not get either a 1/2” or a 12mm to work, or anything else. I got the Topecs and put the 12mm one on my ratchet and pressing straight down was able to back that bolt out after a bit of resistance. Now with a new battery clamp and tray I don’t have to worry about the battery being damaged.