"My batts are (4) 6v, 415AH bats serial/parallel for 830AH @ 12Vdc. Do you know how often they should be brought to full charge in order NOT do damage them? "
Slow death by gradual sulfation is the fate of every battery, but you can speed that up by leaving them less than fully charged. It is only "damage" if it happens too soon for your battery budget. How much effort you put into caring for the batts is situational to your circumstances and the scenario.
What is the battery model/brand exactly? It would help to see the spec sheet for them.
I thought they were flooded, but PT says they are AGM. AGMs need occasional "reconditioning" if left undercharged at times. Equalization of a flooded battery is ok because the gasses go off, and you can water them, but a sealed battery can't do that (unless it vents--oops)
The ONLY way to know if an AGM is truly full on a recharge is to observe the amps it accepts at the end of the recharge while the battery has no load on it.
You must have an ammeter and a voltmeter. This is hard to achieve while RVing when there is a load on the batts. (With open flooded, you can use an hydrometer--wear the same shirt and pants until the holes get too big and then start over with the next set of "battery clothes" )
The regularly scheduled "equalization" on some chargers' profiles like once a week or once a month is not really a desulfation level equalization at all. It is just a dose of the regular "bulk" voltage of 14.x to prevent stratification of a flooded battery. N/A to AGMs AFAIK.
No idea of your scenario etc, but I can say I learned to carry four batteries in summer while on solar instead of the six I use in winter with no solar. ISTR, 2oldman on here, also reduced his battery bank size which was too big for the solar to get done in a normal nice day.
You have serious long drawn out tapering of the amps between 95-100% recharge so getting to proper full is not easy. Especially when the usual blurbs say "full" is when amps get down to about 2% of bank capacity in AH. That is maybe 98% SOC depending. So they are inviting you to be sulfated sooner than you might like.
