Volvo Repair: 2002 Volvo S60 T Electrical Failure, independent volvo, electrical power system

Question
Hi Roger:  This questions concerns my sister's car as she is presently stranded in rural Pennsylvania, five miles from our parents' home in Ohio.  Her 2002 S60 T has only 40,000 miles on it.  Three weeks ago, it would not start after it had been parked at a store.  Towed to dealer/service and they said it was a depleted battery.  Was fine for next three weeks.  Three days ago, she drove from her home in Chicago to Philly area.  On way back today, while driving on PA highway, she got a warning light that said "Electrical Power System Failure", so she called Volvo dealer/service in Chicago who said "get off the road, we cannot promise you can drive it somewhere safe.  She was attempting to get to a safe spot on the road, when the car died, with the additional warning light of "Brake Failure."  Does this sound familiar to you?  Do you think the first problem three weeks ago was not the battery, but something else?  She said that, today, the car was functioning fine until it died.  I'm scared for her, because today's failure happened right in the middle of a highway in a rural area at dusk.
Thank  you very much for your time,
Judi (former Volvo 240 owner. It had 200,000 miles when I sold it.  Still miss the brick.)

Answer
Judi, some of these cars have faulty Voltage regulators in the alternator.  A new battery is great but they should have checked the regulator and check the system for voltage draw.  I would either try a different dealer or independent Volvo shop.  Roger