I have been following this thread for a bit. Primarily because I know nothing about alternators other than they somehow convert electromagnet induction into current going into my batteries.
Having read as much as I can, including everything that Rod has on Marinehowto, I still am pretty much confused. I'll keep plugging away at it. Eventually, I want to explore the possibility of adding external regulation to my Cummins (Delco Remy) alt. I believe it is a Cummins labeled 22SI. It is badged as a 12v 130A amp. Beyond that, I know nothing about it and have been having a hard time finding more specific information.
Alternators and batteries can be a difficult subject to understand.
I stumbled upon this website years ago and found it well written, in plain language and factual.
Chris Gibson the author and the Chief Designer of the Smart Gauge (No, it wasn't originally a Balmar product, Smart Gauge licensed it to Balmar) and all the other Smart Products listed, originally worked at Trace and Xantrex before starting out on his own. He sold the company to Merlin in 2009, and retired to his narrow boat, I think soon after. Smart in these years did not mean Bluetooth compatible so you won't find this on your iphone.
Some of his products remain, although Merlin also offers other monitoring products plus a whole array of other 12/24/48V products, including Balmar and Wakespeed regulators.
Plus they still support this website from 2009. Good on them.
Have a read through this page of the website, even though it's based in the days of lead it still holds lots of truths. Lots of other useful info. (nothing on LFP) also exists on the site.
Bottom line, if you are basically a weekend warrior or stay in a marina with power every few days while out cruising and your internally regulated alternator already charges at 14.3 V +/-, save your money, you don't need a high power alternator and fancy external regulator that you can operate with your phone.
Take the $700 to $2000, buy fuel with it and use the boat more often. It will be way more fun!