Excellent posts before mine!
A couple of thoughts come to mind.
If using a quality monitor, when you observe 12.3V stop further discharging and find a way to bring your camper battery(ies) back to a full charge.
1. Depending on battery type and make, discharging to 12.2-12.3V results in a 50% state of discharge (SOC). Constantly going to and below a 50% SOC will dramatically reduce the useful longevity of your batteries, unless it is a LiFePO4 battery.
2. Solar panels and system ratings are based on absolute optimum conditions. Full, unobstructed sun directly overhead at a 90 degree axis to the panel.
Any angle off will begin to reduce the panel's effectiveness. There is an optimum tilt for a panel. A fixed panel flat on our camper roof's has a maximum 71% effectiveness. Tilting the panel increases effectiveness. Using a portable panel and reorienting it towards the sun every hour or so during the day will enhance that panels effectiveness to ~90-95%. A vast improvement over the fixed roof panel. Automatic tracking systems, primarily for fixed base arrays, have a 100% panel effectiveness.
3. Shading of even a few cells on a panel will dramatically degrade the efficiency of a panel and can bring some panels completely down. So if your fan cover is extended and shading your roof mounted panel, expect a significant degradation. Bike, kayak on roof racks, forget about efficient use of the roof mounted panel.
4. Refrigerator. I generally keep it on setting 2 or 1 depending on the SOC of my battery. I consider the frig a "chiller" and not a refrigerator. I try to put already cold things in the frig rather then warm things needing to be cooled down. Putting warm things in the frig needing to be chilled will cause the frig's compressor to run for an extended period of time and discharge your battery(ies).
Yes, you can spend a lot of coin upgrading your solar charging system. But, implementing proven energy management techniques to conserve stored energy will go a long way to getting the most out of your batteries.
Edited by Advmoto18, 13 February 2019 - 11:20 PM.