Battery Drainage Issues For 325i

[FeelGoodUnInc]

I'm posting this for a friend of mine who owns a 87' 325i.. car is in great shape and has less maintenance problems than my X5, but one major problem that's been hindering him is a battery drain problem.

Basically what he tells me is his car needs to be driven at least 15 miles a day otherwise his car will not start up (the battery dies). Now he's replaced the battery recently but to no avail and has replaced the alternator as well.

I just wanted to see if this has occurred to anyone else, hoping to maybe get some answers here before he has to take it down to a shop. Thanks in advance!