I've got a friend that has a 1983 240D. He bought the car, drove it for a while, rear LCA had the shock shoot out the bottom, replaced the rotted out one, got it back on the road for about 2 weeks, and the alternator stopped charging the battery. The voltage light will come on, and it will start to lose lights, and electronics. Radio mysteriously stopped working all together, and he says its a new battery. Still sounds to me like the battery is bad, he thinks its something in the electrical. Some connection in the dash or some shit. He's had the alternator bench tested twice and its been good both times. And it reads 14+ volts every time I've tested it on the car.