Question-AGM batteries w/ Xantrex & solar

[two2go]

My coach has a Xantrex Freedom 458-10 inverter/charger and two 6v deep-cycle batteries. I do not have a remote control other than the on/off switch for the inverter, so I cannot engage an equalizing charge.

I installed a 50 watt solar panel with a Morningstar SG-4 PWM controller to keep the batteries charged during long storage periods. This part has worked as I usually see 13.2-13.5 volts whenever I test the voltage.

We almost always stay at campgrounds with 120v power, so the batteries rarely get used for extended periods, only for spot use like lunch stops, running the slides in or out, etc. I find I have to add water to the batteries every couple of weeks. I am not getting much life from the batteries (one set of Trojans and one set of Werkers so far). Right now, my 2-year old batteries won't hold a charge. I tried equalizing them with a portable charger, but no good. I am considering the following battery replacement options:
1. New deep-cycle batteries plus a Freedom remote to enable an equalizing charge. (about $360 option)
2. AGM batteries. (about $640 option)

- I know the Xantrex has an AGM setting, so it should be compatible. Will my simple solar charge controller work or will it fry the expensive AGMs?

- Is my solar setup leading to short battery life? Can I just switch off the solar once the batteries are charged without damaging the solar panel?

I will appreciate any recommendation, especially your good experience. I would like to be able to dry camp at least one night. I used to get 4 nights on dual group 27 12v batteries in our former 5th wheel.

["007"]

I replaced my two 6 volt wet cells with two 12 volt AGM's.
Went to FL. LAST Jan. from IN. and camped at Cracker Barrels parking lots all night and must I say it was cold and furnace was going all night. We used the TV for short periods for weather reports and news.
I was surprised they worked so good for us with two overnight stays down and back to N.E.
The altenator brought the batteries up to full charge for next night of dry camping without any problems.
Purchased batteries at Sam's didn't cost much unless you have more the two.
This LINK has good info on batteries and solar with inverters on second page that may help you.

[RV Wizard]

If you have gone through two sets of batteries in a few years there is probably a problem with the way the batteries are being maintained. Replacing the batteries without finding and correcting the real problem will again lead to premature death of the new batteries. I would suggest you check the connections at the batteries and also to the frame ground and inverter/charger. They should be clean and tight. Also disconnect the solar panel from the battery bank and use the battery disconnect switch for a month and then check the condition of the new batteries. If no water needed, reconnect solar charging circuit and retest in 30 days.
If battery bank is good, is properly maintained and used correctly; you should not have to add water to the cells. You could also get about 7-8 years from lead acid and up to 10-12 years on AGM batteries.