The current sent from the TT's battery charge controller is determined by the battery(s) needs, the battery will only take the amps it needs. If your TT has a 10 amp battery charge controller and the battery only needs .5 amps, all the battery will draw is .5 amps from the controller.
The voltage going to the batteries from the TT's battery charger is determined by the TT's battery charger (13.2 - 14.? VDC). They have an algorithm programmed into it (newer models) that monitors the battery voltage, the amps that the battery is drawing from the TT's charge controller, the time that it has been charging and it adjusts the voltage accordingly.
If your batteries need a full charge they will take up to what ever they need, based on what your TT's charge controller max is. If your battery is near dead, you may have to use an external battery charger as the battery may try to draw more current than your TT's charge controller can produce.
The problem comes in when it is not a new TT battery charge controller (old ones) and it continues to send more than the 13.2 VDC (Float voltage) to maintain a charge. This causes the battery to heat up and boils the water and kills the battery, or worse..
Check to see what your TT's charge controller is, # of stages and what its specifications are.
Google model and user manual and you should get it.
Just my thoughts,
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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