I have a 2000X BMW 530D estate, which my father had owned from nearly new. Over the past 8 months it has developed an intermittent battery drain fault and I was hoping you may have some clues about what may be causing it, or know how I can identify the source. I have had it looked at by both my local, well-trusted mechanic, and my local BMW garage and neither has found any fault. The battery can be fine for weeks at a time and then without warning it will be flat. Normally it will have enough charge only to turn the central locking mechanism, but that will be enough to kill it dead. On one occasion it had been perfectly fine for a few weeks but after parking up at a pub for lunch, 45 minutes later and it was stone cold dead, not even enough juice for the locks. Other issues with the car that I guess are unrelated: the remote operation of the keys doesn't work; there are prominent dead spots when accelerating; there's a poor connection to one of the rear lights. That's about it. I don't have any clues about what may be causing it. I'd appreciate any suggestions.