Thank you all so much for your replies. My converter is a WFCO model WF8955PEC. It is rated at 55 amps. It says it has 3 charging voltages (one of them is a 14.4 volt "boost" mode) but does the 55 amp converter rating mean the charging unit can put out 55 amps?
The converter in my old TT took forever to charge the batteries, so I would open the battery disconnect and leave a charger on them overnight. Maybe this new converter will charge them up from a low condition overnight. So far all our dry camping has been followed by several days on shore power, so I don't know what the converter can do in 18 hours or so.