I did worry about my charger having too high amps for the one 100AH AGM battery, so I did not use my 55 amp converter on it.
I used my Vector portable which has 40,20,4 amp settings, so you can limit the amps that way. Now I have the second AGM I can use the 55 amp converter. But I will not be using my 75 or 100 amp converters that I have in my collection on those two AGMs. Maybe I could, but I see no reason to go over the specs when I don't have to.
People with those fancy inverter/chargers can limit the amps output by limiting the 120v input ISTR.