Just wondering if anyone has done this and if so, what did you go with.

I'm hazzarding a guess that the tiny Mini stock battery is "just" enough to power the car systems and that's about it ?!!?!??!?

 

I have a 2004 MC S that had it's original battery installed until June of 2010. Never had any problem with it but figured I was pushing my luck to not replace it since it has been giving service about 6 years.

After much internet research I decided on AutoZone's H5-DLG, it's size, terminal placement, vent capability was considered to be identical to the original battery. It was a breeze to install, no shims, no modification to battery clamp down bracket, pull the plug sealing the battery vent hole and push in the Mini's vent tube.

Specs for this battery exceed the original. 520 Cold Cranking Amps vs. 480 CCA.

Don't have the weight for the original battery but the replacement battery weighs in at 36.4 lbs..

Not cheap, right at $135.00 plus what ever taxes apply. Manufactured by Johnson Controls, hopefully they aren't made in Mexico like Interstate and Optima.

 

Most of the optima batteries or their clones are good choices....since they are all spiral wound AGM batteries, they will not leak or off gas, and they have more reserve...many folks have gone that route in the S.

 

Take a look at braille, a ten pound dry cell battery,
on it's second year in my 2005 MCS.

http://www.braillebattery.com/

 

I put one of these in my car, Even at 20 below zero in Wyoming it works great, 8 pounds lighter with out the cost of a braile

http://www.staabbattery.com/category...Batteries.html

 

Optima 34R is a perfect fit with more power and proper terminal position.

 

I agree with CRoth. The Optima is a perfect fit and has higher capacities. Based upon the way you worded your question, the 34R is the perfect battery for you.

///Rich