recently replaced my alternator on my 99 chevy prizm with a custom built cnc machined apex alternator due to the stock one failing to charge anything above 12.3/12.5 after replacement it ran did freaking amazing anywhere from 14.9 to 15.2 with headlights and ac on. about 3 days later i was playing music and my system completely cut out, and i look at my voltmeter and its down to 12.3 again! the car has a assload of grounds, one straight from the alt to the bat, to alt to chassis, and a 00 charging wire straight to the battery positive, my amps in the truck have a dedicated 00 ground to battery and a chassis ground aswell. all of my connections seem to be super solid and have no play. i cant seem to figure out what the **** is going on with this thing and its driving me nuts cause i daily it in the summer and have a show to attend on the 5th, if anyone has had any similar issues please let me know if you ever found a solution. or if you have any ideas as to what could be going on. thanks for reading