Vampires and multimeters

Well, them SOMETHING you do while camping is the culprit.... or the batteries have much less capacity than you think they do.  Without better instrumentation and data, there is no accurate way to tell.  

But some possibilities I can think of would be:

1.  Water pump firing intermittently all night.  

2.  One or more lights is NOT an LED and is on and drawing more power than expected.  For example, all interior lighting in our 2014 171 is LED.  However, our porch light and trailer hitch lights are incandescent.  

3.  Brakes engaged?  Feel the drums after a while and see if they are warm.  

4.  Faulty converter, drawing power when not charging.  

5.  Vent fan running and drawing lots of power.  

6.  Refer drawing more power than expected.... like either defective or running a mullion heater or defroster (just guessing).  

7.  Trailer plugged into the tow vehicle and powering something unexpected in the TV.  

Draining 200+ AH of battery from 12.8 to 12.0 overnight is a LOT of power.... if the batteries are healthy.  That would be a 10-20 amp discharge and more than ANY single device in an Rpod should draw.  But as was said earlier, if you can't identify the culprit you MUST measure the steady state drain directly from the battery in "camping" mode or you will never know what is going on.  

Paul

Is the refer on battery power and you don't know it?  

Is the water pump activating periodically due to a leak somewhere?

Are the brakes on?  I had not actually thought of that one, but if the breakaway pin got pulled....

Are you absolutely POSITIVE you are measuring the total battery current?  

Try installing a 12V wattmeter as a temporary monitoring device and see if the total discharge power makes sense.  See this (sorry, can't get the danged embedded link function to work on this site so here's the full link):

https://www.amazon.com/Power-Analyzer-JZCreater-Backlight-Precision/dp/B01LVTST80/ref=sr_1_1?ie=UTF8&qid=1502207485&sr=8-1&keywords=dc+watt+meter

Put it directly inline with the battery.  Either you ARE drawing a lot more current than you think, the batteries are bad or they are not at the state of charge you think they are.  And I just realized that you are (I think) measuring the current across each fuse position when the fuse is pulled?  That may miss things like parasitic currents in the converter if it has an issue.  Or any other potential loads that are not fused (like a defective solar controller).  And don't get confused about the state of charge on your batteries.  Measure with a voltmeter on the batteries when the solar system is NOT charging.  The Renogy controller that I have displays state of charge but is only accurate while charging (it is the way it is calibrated).  The battery meter in the camper is only accurate when the battery is NOT being charged.  You may not be as charged as you think you are.  

Paul