electric mystery

I have a 91 Euro. She is a good car but she is sick again. I replaced the battery in Sept 04. Now I can be driving down the road and all is wll get to where Im going and have her not start, there is power not enough though to start her again. So that sounds like a starter issue right? well now she will lose all power at 50 mph and die on the spot. No warning no temp rise no oil pressure drop. No dummy lights nothing and thats it.
Get it towed hubby drives a truck my hero lately. put a jumper pack on it the next day and she starts and goes fine again? I dont even know where to start. A friends mom gave me the car and she says its always been electrically unsound but this is the first its done this to me. Im looking for any advice on this. Please and thank you

it sounds like maybe a bad voltage regulator in the alternator, or possably just bad conncetions. Remove the battery cables, and clean them up, and put them back on.

this is the hubby/tow truck driver- the entire charging system checks out fine. alternator is putting out 14 volts and 14 volts is making it to the battery. when the car is turned off and allowed to sit, the lowest battery voltage reading is 12.7 volts. the battery also load tests good. there are exactly 0 codes stored in the computer. there is no reason why this car should be running off the battery until it dies, but that's what it does. the battery terminals and the aux + terminal are all clean and tight. there are no shorts or draws. sometimes the car drives fine and then out of nowhere it starts cutting out, the lights dim and then it dies. it has all the symptoms of an alternator or internal regulator but everything checks out normal. we've had this pile for about a year and this is the first major problem. it all started about two weeks ago. i guess these are good beater cars but not something to be trusted. by the way i usually tow about 12 cars a day. i tow an average of 6-7 luminas every week. not very good odds. my old lady says i should say what i tow the most- luminas. just kidding. she just slapped me. she likes her car. i don't. never have. the most common make i tow is chrysler. the most common model is the chevy lumina from all years and for various malfunctions. i don't even tow half as many kia's. seriously if anybody has any ideas, i'm listening, but it's not going to be an obvious solution.

damn, tough one here. Make sure the wires connecting to the alternator are good. There should be one think power wire, and one small plug. Make absolute sure that plug and wire is in good shape. Maybe unplug it, spray it with a little wd-40, and reseat it. You'ld be suprized at how much this helps. Um, still to me sounds like an alternator issue. I would probably rip the alternator off completly, bring it to autozone, or your parts store, and they should be able to bench load text it for you. And if nothing else, that will clear the alternator as being the problem.