1995 Toyota Tercel Electical shuts down when AC runs

A/C was recently fixed (new O-rings and system recharged). While driving on highway with AC on, first the radio and clock stopped working, then a few minutes later, the car stalled. There was still electric to the interior and lights, but the car would not restart. I had the car towed home and tried to start it there - it worked fine and all electical was back. The next day, I was using the AC while idling, then drove back to work - again the radio and clock stopped working. Shut off the car and tried to restart - it would not. I let it sit while I worked, and it restarted with no problem. The car did not over heat, and other than the shutdown/no restart, the car seems fine. What could be causing this?
I just got the car from my mom and she has never had any problem with it, although she never used the AC very much.