2002 Toyota Corolla Running out of power

Engine Performance problem
2002 Toyota Corolla 4 cyl Automatic 88000 miles

Car has been relatively trouble free until about two weeks ago. We drove it about 150 miles on a trip, partly at night, the dashboard lights dimmed, the check engine light came on, and we barely had time to get off the highway before the car stopped. It was towed in, alternator checked out fine (had one installed 8/06) but battery was replaced. "Check engine light" stayed on for no apparent reason. Car drove fine for about two weeks, mostly daylight hours, then on the same 150 mile trip, after dark, car stalled again. This time the alternator again checked out fine but the battery was said to be non-functioning, and so was replaced with a new one. "Check engine" light went out but came back on the next day for no known reason. Two days later, on the return 150 mile trip, again after dark, the same thing happened. The battery light came on, the lights dimmed and then the car lost power. However, after about a five minute stop, it started again, the battery light went off, and we made it the remaining 25 miles home. If anyone has information about this situation, we would be most grateful. Thanks.