The battery on my 2014 Countryman S is on its way out. When I enter my make/model in the filters on Autozone, Advance Auto, etc., it returns batteries listed as Group Size H5 and Group Size H6. I assume both sizes will work, but does anyone know which size is the best fit? They both say "Exact Fitfor your 2014 Mini Cooper Countryman S ALL4" but obviously only one size can be an "exact" fit, while the other would be "close enough" fit.

 

Most likely H6. It should be a snug fit, the H5 will work but is slightly shorter.
Just measure the length - I found some of the catalogs are not quite correct.

 

Ensure that the battery is programmable (coded) to your Countryman.

 

Thanks. I picked up the H6 size from Advance Auto. I had my core with me and lined them both up at the counter and they seemed pretty close in size. No problems getting it installed.

 

I have the diagnostic tool coming from Amazon tomorrow to do exactly this.

 

What tool did you go with? Let us know how it works out when you get it done. I recently replace my battery with an AGM and had a friend do the programming. What a general pain in the *** really...

 

I got this one:
I went through the menus and was able to register the battery. Not entirely intuitive, but it seemed to work and the tool confirmed that the new battery was registered. I also scanned my BMW 335i, which had a whole mess of codes come up, a few of which the reader was unable to erase (i.e. it said it successfully erased them, but when I rescanned, they showed up again). Going to need to dig into those to figure out what they mean.

 

There sure seem to be a ton of various options when it comes to scanners and such just looking at Amazon... That is great it worked for the Mini and register the battery. This is my first European car and I'm not really a fan so far based on having Asian vehicles for the most part.