Not freeze over but instead it warms up inside when the outside is very cold say @30F and lower. My sensors showed upwards of+6F above the normal settings of 32F top & 40F bottom. I suspected a LP flow issue but the heater, stove and a bbq plumbed at the tail always work great. I’m not aware of LP being significantly impacted with these temps so I'm leaning towards the refrigerant thickening (? for lack of a better term) as some percentage of that chemistry is probably water. This happened with an earlier unit too which was +10 years old until I replaced it 2 years ago due to parts failure and the condition continues. Other than a battery whisper fan circulating inside, both are factory with no mods. I tested at home on shore power and can’t reproduce the condition under simulated full hookup. There’s no problem LP off when on the generator. My next test will be in the field is to confirm if compartment heating without killing the batteries in freezing cold alters this. So, I’m looking for a power friendly solution, or any other solution, if there is one. I'll figure it out at some point and will share the results.

Ray, Thanks for the expanded explanation. I have friends with PO4's and they swear by them thus they remain on my radar. Think I'll let the AGM's proceed to the end of life and decide then. Thanks again.

Within the last couple of weeks there was yet another spontaneous Lithium battery fire news story thus I continue to consider the technology still in it's infancy.. I'll stick with AGM until a time when it's been around a year since seeing this issue repeat itself. I'm interested in switching one day, just not today.

I solved all my fill related issues such as described (and more) with this, never tried the faucet open hack. Cut my unattended fill time by just over 1/2 too: http://www.valterra.com/product/secure-fill/