First time mini owner here. So sorry if I ask obvious questions. I believe my bcm or frm is bad (if car has both). It all started back in December when I drove on a bad snow storm. On my way home all my lights in the interior went out. But the exterior headlights. Lost heat. Power steering. Windows. All electronics pretty much. The next morning. Car was fine and it went okay for a few weeks. Then it started to happen again. More and more often. Eventually the battery died. And I thought it was a bad battery (less than 5 month old) went to auto parts and got it replaced. It died again. A friend said it might be the bcm or frm. So I found one in a r53 mini in the junk yard. But that car did not have a sunroof like mine does. Haven’t had the chance to remove mine (bottom of passenger side right). For now I been plugging and unplugging my car battery to be able to use the car. When the issue occurs. It does smell like burnt wire while driving it. Again the issue goes on and off. When I come to a complete stop it goes back on. As soon as I hit the gas in first gear everything shots off. Any ideas or advice?
thank you

 

I'm a bit of a novice but pretty well versed in working on my 04 R53 for the past 15 years...
Just a thought -
#1_ Check your belt and belt tensioner for wear/slop.
Your belt maybe stretched/ causing slipping
#2_ In addition; If you are still running the factory rubber core crank/harmonic pulley, It maybe that that burnt rubber/wire you are smelling may be from a failing (rubber core) crank pulley - Which in turn may also be suspect for "slipping" = not turning the alternator enough to maintain enough battery charge.
Just a guess?