Ok, so three batts are say 300AH whatever. 12.4 is 75% so AH is 225. so add the 33Ah used that is 258 before dark or 86%
With two house batts it is 12.1 or 50% with 33 used. So if 200AH down to 100 and 33 used, that's 133 or 66% before dark.
So yes, the two house batteries are hurting compared with the engine battery, however old it is. if those figures are correct.
If the solar is in question, IMO as a fist step, go panel direct onto the house batteries and see how that comes out--no controller. Then compare with controller on line. Next step depends on results of that.
