Just to dig further into your set-up :) What is the spec upper voltage cut off for the inverter? Mine are both at 15v.
If they alarmed off at battery 14.8v that would mean a voltage drop between battery and inverter (wires too thin for their length) at the current being drawn at the time by the inverter with that load on it.
In the same way, your solar controller voltage display will show a higher voltage than the battery's actual voltage depending on the current at the time on that pair of wires.
Any voltmeter inside the rig far from the batteries will also read high compared with actual battery voltage.
One of the hazards of the solar controller set-point is that it will "see" its value before the battery is actually that high if the voltage drop is not small on the controller-battery run.
Without knowing what is really the situation, from what the OP has posted about all this, I am getting suspicious the batteries are maybe not seeing the voltage he thinks they are getting, and also that the inverter-battery wiring is suspect.
Yes/no?
EDIT--RJ, it is not we "voltage fanatics" who are saying 14.8v for Trojans, it is the Trojan company! If it comes to a choice of believing Trojan about their own batteries or RJ about whatever his are, guess what? My goodness! :(
