When changing out the battery on my 2015 Sonata Sport I loosened the wrong nut and of course it dropped down below. I've tried taking the bottom panels off, kind of banging them to figure out where it was. It's just gone somewhere. I am not able to find the specs anywhere for the nut. I think it's 10 or 12 mm, but I don't know the thread spec. All the dealer could find was to sell me a new battery cable. It's probably $0.20 at the hardware store if I knew what size. Any ideas?