Dometic Fridge on 8 AA batteries?

Congratulations on your new RPod. I hope you have many fine adventures and make many great memories doing so.

Okay, if you have a good battery, it is superfluous. Your 12V battery (or, if you did like I did and install dual 6V batteries wired in series) will provide all the power your refrigerator needs to run for quite a while if you don't need power to run anything else. However, in real life, the refrigerator is not the only draw on power. There are also constant power draws from the LP/CO detector and the thermostat. If you forget to turn the antenna booster off, that also draws power as does the entertainment unit and the USB charging outlets. You won't want to leave your 'Pod disconnected long unless you put in a battery disconnect switch (or just disconnect the negative terminal of the battery). Be careful if you disconnect both battery terminals to note which wire goes to the positive and which to the negative. Connecting them backwards means at a minimum that you blow the two 40A fuses in your power panel that protect your converter from reversed polarity.

Could you possibly find a battery box that fits that space? Maybe. Do you NEED to find it? questionable. I don't really think you would want to use the refrigerator in your R-Pod with no lights, furnace (in cool/cold weather) or vent fan ( in warm weather) anyway. You would be better off upgrading your battery to dual 6V (lots of power but relatively heavy but also relatively inexpensive compared to other options) or LiFePo4 (Lithium) batteries (light weight, great capacity, very expensive still and need an adjustment to the converter to properly charge). Ultimately, you could really build a high-capacity power bank with the LiFePo4 batteries that would weigh much less than dual 6V and have more usable capacity.

I do think its interesting that the manual states the fridge goes into a power saving mode when on the main 12V power is disconnected and its on the AA's. Not sure why Dometic wouldn't put the fridge in that mode whenever its running on propane. That would be helpful, and maybe there's a way to set that up. 

Good luck in your research, please let us know what you find out. 

Thats a possibility of course, the cost for the part might be stupidly high or even made out of un-obtanium. But I think installation should be easy, the little battery drawer slides out from the 'eye-brow' of the fridge.

I bought (and briefly used) a Battle Born LiFePo4 100ah battery for one of my other trailers and that thing is just begging to be dropped into the r-pod. 

I know the factory WFCO converter charger is not rated for lithium 'per-se', but the Battle Borns are designed as a 'drop-in' replacement for lead-acid RV batteries.

Let the spending begin!