I'm relocating my battery to the spare tire well in my 94 Formula. I used to have an amp back there and I grounded it to the bolt that used to hold the rear seatbelt in place on top of the rear wheelwell, and it worked just fine. I am wondering if this bolt is adequate for grounding the battery to, or if I should find somewhere else. It's a nice, convenient spot that's inside the car and completely hidden, so it is ideal in my mind as long as it'll make good contact. Thanks in advance.

 

Do you have a Digital Multimeter?

Check the resistance from this ground point and your negative battery terminal. If it is 0, it should be sufficient.

Make sure all the paint around it is scraped off too.