Battery Brake light

Spressler

So I have an interesting issue with my Murano- The Brake/Battery light has been coming on intermittently since I got the car a few months ago. Both the battery and the alternator have been tested and they both passed. When I am sitting idling the car will have these power surges and that light will pop on then after a time will go back off. Now last night my fiance reports the car began to die as he was pulling into work. He had it jumped started it up rolled the windows up and then later when he left work it was dead again. Then this morning I had to drop him off at work and it died on the highway again so we pulled over charged it and were on our way again. After I dropped him off at work I charged the battery again then headed over to advanced and had them test the battery and alternator. Both tested fine. hmmm So I started thinking maybe because I had just charged the battery not 10 mins prior it was messing with the results. So then I drove home (About a 30 minute drive) and went to another Advanced closed to my house and repeated the test. Same. Both were testing fine. What?! Any ideas whats going on?