Alternator stops charging after 2 months

In May of 2020 I bought a 90-01-4513 alternator to replace a Delco Remy 36SI. This alternator is a factory refurbished model and is rated at 160A. It has A 14gauge remote sense wire with a 5A fuse located 6 inches from four 990CCA AGM Deep cycle batteries in an '06 Western Star. The alternator charges all day at 2 and 13 AMPs and maintains a voltage about 13.5V. I have a large stereo 1000W but a 20 farad capacitor feeds both amps and consistently maintains 14V that it sips from the system. When the truck is initially started it will put out 50+ amps for a short period of time to replenish the batteries. I have a 5000W pure sine inverter with two pair of large cables, 200A fuses and a casing ground wire and once a day I cook a meal with the truck running at high idle. The voltage never drops below 12V and the alternator will peak at 90A and this will continue for anywhere from 30-60 minutes. I did this routinely with the Delco Remy but after two months the Wilson suddenly stopped charging. I replaced it under warranty through O'Reilly's and low and behold within the same time period the 2nd one also failed. This is a 160A rated alternator and I just cannot accept that this product isn't capable of this. A benchmark certificate came with each of them showing twice that, 183A tested after rebuild. How can they be failing? All I really overworking them. I've sent the scenario to Wilson to gather their response. In the meantime I still have my Delco Remy 36SI and believe I will diagnose and replace the failed components and have it ready this time. I better get cooking as it would seem I only have two months. Of course, there's still 7.5 months left on my warranty.

 

That sad the first thing I was going to check. I've just replaced a broken hinge plate that made opening the hood a major production. Starting tonight I'm be taking my temp gun to monitor.

There's also one ground cable at the batteries that has considerable frayed and broken strands, so I'll be replacing the lug on that cable as well.

 

I think 165A is plenty for what I'm doing. It never calls for more than 90A. And stock was 135. I'm antsy at the threshold of larger cables.

 

At the threshold of larger cables - that last post should say.

Seems to be 120°f after 13h drive (CA legal)