Rep Power: 0

I’ve been driving my car and when i first start it it doesn’t seem to have any problems at first but then when i was pulling off the car seemed like it was cutting power a little bit because my power steering was kind of rough and the lights were dimming. When i pulled up to stop lights the car would do the same thing and then when i got home and it turned it off it completely died. When i put my key in and left it for a second everything turned back on. I checked the battery and the connections were secure and i also had the car running with the positive disconnected to check the alternator and that was fine as well. Does anyone know what this could be?

 
Rep Power: 229

Loose alternator belt tensioner?

I had a loose tensioner, when I accelerated the battery light would flash on, and electronics would dim. It eventually drained the battery.