Alternator Output under load??? HELP

[280zNHChris]

My old belt was oily and spent but deflection was fine. Car would go for a couple weeks then dead battery. I put a new belt on and cleaned all the grime of all the pulleys. Car ran excellent after. I used a multimeter and Blue's link to testing output with a multimeter and before the belt was changed with headlights on high, wipers on high and heater fan on high, the meter read 12.74 which is to low supposed to 13 or higher. After the belt change under the same load it read 13.64. Perfect I thought, car runs way better, charging light is not dimly lit anymore. Just to make sure I go back to autozone and the same guy comes to test it, says it looks alot better, but when their "Machine" puts it under load it reads only 12volts???? I ask him why the difference in readings and he says their machine puts a "bigger" load on the alternator. My question is if it reads all good under the "cars" heavy load, is it fine??? Or is that machine for newer cars with much more electronics in them and thats why the "load" is so high? or is my alternator really not up to the job?????? Before I put this new alternator in can someone give me their opinion?

Thanks Chris

[AK-Z]

I believe that their machine puts the alternator under a heavier load because of quality control. An alternator that can take a heavier load should be able to take a lighter load with out any problems. Its over testing, so they know that it will be able to take more than what it load environment is going to throw at it.