With a 8 month old battery one day my battery indicator light came on. Found a few dry cells and refilled with distilled water. Recharged battery and drove again but light still came on. Battery and alternator checked out OK at auto part store. Replaced voltage regulator as brushes were at minimum length. At this point everything worked fine for the next 3 months, even during a 800 mile round trip. Then battery problems started again. The battery was replaced and still runs down. The dash battery light isn't coming on this time. Had to be jumped and on the way home the lights were very dim, no blinkers or dash lights. Suddenly, at about 60 mph, the lights all came on. Any suggestions as to what is going on with my 1987 190d.