Basic battery charging and solar question

OK, here is the scoop. You need to get a volt meter. The battery indicator on your panel doesn't tell you much. 8 chances out of 10, your trailer will have a WFCO power center. Open it up and find out. While the newer WFCO converters are ok, they are far from the best thing for your batteries, especially being plugged in 24/7. The WFCO advertises 3 modes but it will never go to float mode and it will hardly ever go to bulk mode. A WFCO converter/charger is stuck at 13.6 volts most of the time. While this will not hurt your batteries, over time they will lose water so they will need to be checked every 3-6 months. That is why you need a volt meter, to know what is going on with your batteries. Also google "12 volt side of life" and read it. There is some very good information here. Your service tech is misinformed regarding this matter.