Thanks for the comments and suggestions. I think I need to clarify a few things as a few of the suggestions seemed to focus on the wrong issue in my opinion. What is unique about this camping experience is our twin baby girls that required us to heat their bottles multiple times a day and to keep the furnace running at night because at their age you can't cover them in blankets.
The bottle warmer pulls ~300w for 10 minutes 4 times a day. The wife's coffee was ~700w for about 4 minutes each morning. Finally, we have running the furnace in the evening which was ~100w for about 5 minutes but cycling probably one to two times an hour from midnight till 6am. The 200w of solar is usually fine for our "pre-baby" camping needs during the summer but with these new needs and less sunlight in the winter months, just was not enough to get the battery topped off each day.
Next year we won't be doing bottles or need to run the furnace as aggressively so those factors will go away. The coffee pot we can run the genset for if really necessary though I think without the other two factors, the coffee pot isn't going to be an issue.
The point of my post however is that what I did discover is that the LiFiPo4 battery when it gets cold will limit it's charge rate. This was a bit of a head scratcher the one morning when we ended up with a dead battery so I started the truck around 6am (~20 degrees outside) in order to be able to run the furnace and put some charge back into the battery. I found the battery was only charging around 3 amps when I have a 20amp DC to DC charger. It took me a while to realize it was the BMS on the battery limiting the charge because of the temperature.
Moving the battery inside is just a project I am considering because I have a pretty optimal location for it that would eliminate the cold factor. In normal use I don't think I really need to add more battery capacity but will eventually add another 200w (for 400w) total of solar power. I might also replace the furnace with a more efficient two speed unit as well.
