Hi Joe! You may need to trickle charge your batteries if you don't use the RV for extended periods of time.
I'm not familiar with a TT. Does it have a converter that charges the batteries when plugged into shore power? If not, OR if you don't keep the RV plugged in, then you may want to buy a small "battery maintainer" or "trickle charger", maybe 1.5 to 4 amps, and leave it connected to the batteries when you are not RV'ing!
If you do this, just be sure to check the water level in the batteries at least once a month and top them off with DISTILLED water when needed!
Good luck, happy trails, and God bless!
Joe & Annette
Sometimes I sits and thinks, sometimes I just sits.....
2002 Monaco Windsor 40PBT, 2013 Honda CRV AWD