To my knowledge, when off the grid, and on a generator, charging with a switching power supply set at 14.8V, there is only one thing limiting the amount of current it will send into the battery.
That would be the battery or batteries resistance to taking a charge based solely on the battery chemistry and how much sulfur is still on the plates, and not in ionic form as sulfuric acid in the electrolyte.
So the PSU sends only what the battery chemistry can take. That is it, that is the limiting factor. I am, of course, comparing a 36 amp or 30 amp PSU to a 36 or 30 amp PD, or Iota. If you want to run a pair of MegaWatts through a Schotky diode and lose .4V off the top of the 15.4 to 15.5V a MegaWatt is capable of, then so be it, but then you can pair a set of them for 60 amps, or 72 Amp capacity.
Compare the amps you get for the price of $50 or $60 for 30 or 36 amps, to any other PD or iota of like amperage, then get back to me with what you paid for your PD or Iota for the same amps. I think in the smaller sizes, you'll find the price per charging amp to be quite a value.
Caveat: I run off a small 158 Amp hr AGM now, it's resistance is a lot lower than the Trojan T-1275 I had previously. The T-1275 ate 14.8V like nothing. It was beat up and sulfated when I got it. I routinely thought nothing of whacking it with 15.0V and 16.0V when I got it, to clean it up, top charge, it, then equalize charge it. It took 3 attempts and about a week, with days in between, to finally get the last cells SG up to where it was correct, with a manual battery charger.
The AGM is like nothing I've ever seen before, it's capacity for amps during charging when below 85 or 90% is hard for me to comprehend right now, even at only 13.5V, the recommended bulk charge voltage.
14.8V is only the magic number if your battery manufacturer says it is the magic number. Don't forget the Screwy 31 by US battery had a recommended top charging voltage of 15.3V. The battery manufacturer has final say for magic voltage, not the charger manufacturer.
