Hi I'm wondering if anyone can fathom this one out. I have owned my Mercedes E Class W211 320 CDI (52 Plate) for one week now and had problem after problem, latest one is the battery warning came on yesterday saying consumer units shutting down, today the car thinks the battery is dead, I have checked with a meter and it was reading 14+ volts on both batterys, but would not start, then went back out and tried again 1/2 hour later and car started but now battery in boot reading 11.6 volts while running. Switched off and tried again 1/2 later and car won't start again but battery now reading 21 volts, Whats going on? I'm getting fed up with constant problems already. Can someone help? 
