Pull the main fuse by the battery or pull the positive cable off of the battery. Take the voltage when you disconnect the battery from the TT. The voltage should be 12.6 or higher (should be 13.3 if the charger was just disconnected, this is know as the FLOAT stage, keeping the battery topped off voltage). Let the battery sit for a day (battery at rest) and then take the voltage again. The voltage should still be 12.6 or greater. The Interstate 85Ah battery that is sitting under my workbench (use it for different low voltage projects) has not had a charge on it for over a month and it is at 12.93 yet. The other battery is still in the shed and just checked that one and the voltage is 12.78. These batteries were mfr in July of 2012.
The main thing (maintenance wise) is to keep the battery water level a 1/4" above the plates, yet below the ring you see (keeps from splashing through the battery cap vent hole and on top of the battery), also make sure that all your terminals are tight and CLEAN. That is pretty much it for maintenance.
The one thing that you need to keep in mind about sales people (auto parts, RV sales... ) is that they are looking to pad their pocket books, and as for RV sale people, they know nothing about batteries or electronics. To MOST of them they can make a good battery look bad. (Cha-Chingh)!! The test that they do at auto parts stores using the load meter is primarily for automotive batteries. They test for cranking power. Which reminds me my truck is down to the 520 range, almost time to replace.
The key thing to remember is when you are not using the TT, pull the main fuse.. even when you have the battery on a SMART charger, less power goes to the TT electronics and more to the battery.
Here is what a smart TT battery charge controller (the one in my TT) output looks like over time.
Hope it helps,
2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package
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