No, you are mistaken, it's been set up great, and worked daily since 2017, thats 6 years living on the boat with th A2B charging at 140A flawlessly almost every day, until just recently. I charge the AGM bank when they drop to 12.3 or 12.2 volts. i can get about 8 - 10 hours watching 4k movies before charging. all of a sudden i now get 15 minutes until 12.3v and the charge light is dim on the ignition, i get over 17 volts from the exciter wire.
I think the alternator has over volted the AGM bank and failed it, i could only get 30A from it instead of the 140A it was the day before but the voltage seemed to stay stable.
Today i noticed the over volts light was on on the charger, it was at 15.8V at the alternator input on the charger, same on my AGMs. It was producing 30A and red hot at high rpms. no lifepo4 connected. after 10 mins charging.
The alternator is screwed, what you see does not correspond with reality. Its just your own issues that make you see things that are not really there, only you can do something about that, nobody can do it for you.
I do not want to put the my new LiFePO4 battery on this alternator, the reason i purchased it was because it was the same price as 3 new AGMs that got destroyed from 8 hours use down to 15 mins after 1 charge cycle. the charger does not protect the bank, just puts a red led on in the engine room where nobody can see it.
Sterling power will not give me the part number for the regulator and the number on the regulator does not correspond with anything anyone can find