I recently purchased my own, having borrowed my friend's one a few times. These will restore a pretty flat battery, and even reincarnate a dead battery - as long as it's not too far gone - with it's clever charging modes. I've just restored a very dead and neglected calcium battery over the course of two days of conditioning using an MXS5.0, and am delighted. Still, you shouldn't need to go there given it works as an intelligent battery maintainer as well (perfect for your garage queen/race car/sunday driver). Has modes for motorcycle and car batteries, and also has AGM mode. There are useful accessories (not yet carried by FCP) such as a rubber bumper kit (avoid scratching paintwork), and a quick-connect module with 3-LED battery condition indicator. You know you want one!

Every BMW should own one of these... this appears to not only charge the battery, but condition the battery while slow charging.... thus extending the life of the battery... thank-you FCP for carrying great products!