I agree 20 amps would be undersized for a 225AH bank for normal charging purposes. However, I think an equalization charge current is substantially less than you'd put into an discharged bank for a typical recharge. While batts might accept ~20-25% of AH capacity in current when fully discharged, the current going into a charged bank is substantially less, around 2% I read on one battery website. The equalization charge is supposed maintain a charge at about 2% of AH capacity while the batts overcharge to around 16v, according to what I read. That would be about 5 amps. This Ample Power website suggests 3-7%, which would be about 6-15 amps.

http://www.amplepower.com/primer/equal/index.html

I intend to apply the equalization to a fully charged bank, as so I should not need the 40-50 amps that could be put into a fully discharged bank.

That's the theory, at least. Like I mentioned, if it overloads the charger I'll just do one or two batts at a time. Since I only need to do this every few months its not much of an inconvenience, and beats dropping hundreds of $$ into a new 50 amp charger, at least for my situation.