It's under the hood on the passenger side, tucked up under where the wipers are located. You need to pull off the rubber molding on the rear edge of the hood to about halfway across the back of the hood and pull the firewall cover back to get to it. I'd go to an Interstate Battery store. They will put it in for you.
it's pretty hard to see at a glance but it is there. A black plastic cover is located under the cowl on the passenger side. There is a red, hard to move, cap on the positive end
Search MINI Cooper Questions
MINI Cooper Experts