190e Power Failure? Stall
 

This is probably about the third time this has happened to me.... I have been through numerous batteries and now I am on an Optima Yellow Top. I have a very powerful car stereo system, 1600watt rms with the stock alternator. One time all of the lights in my console came on and the car stalled, another time the rev meter started spinning, and this time all of the lights in my car dimmed [console,hud,headlights,headunit]. I turned off the radio and all returned to normal. I was told that my stock alternator [190e 2.3 1991] is 70amp. Either it is shot, or not strong enough for my car ? I was told i can do a 95 s420 alternator thats 150amp, if i recall. Any recommendations you may have would be greatly appreciated because I have been stranded one too many times.