1991 300e voltage regulator

[lebstyle]

hi, today while i was driving on the highway, my lights in the dash started coming on, then all the power stuff in the car started shutting off, then slowly the car loses power, then it turns off. i boosted it a few times till i could get back home by a friend. it didnt seem like it was charging.
but when it stops, there is still power in the battery, it doesnt completely die, but not enough to start the car.
i took the voltage regulator out, and one end is bigger than the other. they both are spring operated, one is pretty short, and one is a few centimeters longer.
could thing be the problem, or should i build the whole alternator.
b/c a couple of weeks ago i was on the highway and the same thing hapenned, but then it would kick back in while i was driving, so it never completely died on me. and for the last 2 weeks it was find in the city till the other day i forgot the lights on and the battery died, then i got this problem again.
here is a picture of my voltage regulator.