[Pirateradio]

Sorry to hear of your problem. This week I experienced somewhat the same thing - twice.
Driving along, one by one each light (SRS, ABS, etc) went on, and then lost power, give it gas, was going nowhere. Pulled over. Battery dead. Wait a minute, starts for a bit, then dies again. Tow to garage. Assume it's alternator not charging battery. Replace alternator and battery.
Next day, Everything ok. Drive 150 miles to OC.
Nighttime return, same thing happens. One by one each light comes on, car decelerates, giving it gas does nothing, car completely conks out. Battery dead again.
Tow to Merc dealer.
They replaced something called Voltage Separation Relay (was a fault in it), which regulates volts going from alternator to battery. Probably didn't need a new alternator after all.
Now all is ok.
Perhaps have that checked out?