Any help with this gratefully accepted, my 1989 E 34 535 i has taken to discharging the battery overnight, draining it to zero volts, the battery is a new Yuassa correct heavy duty one, every now and then it does this, I have but an ammeter inline and monitored it for several hours and never seen more than 1 amp drain at any time. I have tried removing the wires from the alternator and still it will drain the battery overnight, no fuses are blowing, nothing appears to be running. Any ideas ?