> What size Inteli-Power should I get?
Your choice. There is nothing about AGMs that dictate the size of the
Inteli-Power.
>
> Do I have to do anything different with the Inteli-Power when using AGM
batteries instead of lead/acid?
No.
>
> If I add more AGM batteries in the future, do their sizes have to match or
could I get larger ones than I currently (or soon will) have?
They should match.
>
> Roger, how are you recharging the AGM that isnt hooked to the Solar? Are
you plugging the Inteli-Power into the Inverter?
That AGM is kept charged by the Inteli-Power. The two that are charged by
solar panels are not connected to the Inteli-Power in any way.
Plugging an Inteli-Power into an inverter won't work. Remember, the
Inteli-Power is simply a battery charger/12 VDC supply.
I set my system up like I did because I sometimes need limited AC power when
boondocking. I can use the two AGMs and inverter for that. In a pinch, I
can also use that AC power to charge the other battery through the inverter,
although I rarely have to do that. It's worked for me for a few years now,
and I'm happy with it.
Roger Hightower, WBCCI #4165, VAC
1975 31' Sovereign
2002 Ford F-250 PSD