B1B... You've without a doubt damaged your batteries by allowing them be completely discharged. But...you need to now charge them to 100%. If you are plugged in...you can do this with your converter AND the battery cut off switch to ON so that you can see your overhead 12V lights come on. Leave plugged in to your converter for at least 24 hours....then disconnect the NEGATIVE battery wire for 24 hours. Then go back to your battery posts with a voltmeter and you should measure 12.6 or 12.7 Volts if you were able to take a full charge. Anything less is battery life lost and anything less than 12.4 indicates significant damage. You can still use them when plugged in and for brief periods of use... but I wouldn't boondock with them.
Anything less than 12.2 and you should be making a trip to walmart for some new ones.
Good luck with the recovery. Suggest you get one of these cut off switches for the future to insure the parasitic loads that still exist when you have the batt cut off engaged (propane detector, station presets etc.) can no longer hurt your battery.
Always leave the coach with a 100% charged battery.
Walmart, Amazon & Ebay have them for under 7 bucks.