We boondock quite a bit and find that 2 golf cart batteries(6 volts each) will provide the most power for the longest time.  We also use a 100 watt Renogy solar suitcase system that keeps us in power for days oif we can get about 4-5 hours of sun.

the GC-2 batteries are available at Costco and Sam's club for about $110-115 each. It will require another battery box and one additional connector cable to install. 

Use the search function and you will find lots of additional info about batteries-they are always a big topic.

Do not use the battery power for your refrigerator-use propane. the refrigerator use a lot of power and will drain the batteries pretty quick. the other big power user is the furnace fan. It doesn't take much to heat the pods and there are several alternates tot he on board furnace.  Several types of propane heaters that require adequate ventilation.  also, a small electric cube heater is used if you are plugged in at a campground. they are very efficient and you are already paying for power.

Welcome and safe travels

Vann

You don't say what tow vehicle you have but before you get dual batteries you should be sure you can handle the tongue weight, which will go up quite a bit. You might also want to get a dual propane cylinder setup if you're using the furnace a lot. Same issue with tongue weight there. Or, you can just take the second propane cylinder with you in the tow vehicle. It's legal to do so if its kept vertical and secured in place. 

As for solar, if you're frugal with power it might work for you even in winter with poor solar irradiance but you might also want to consider bringing a small generator. Or, if you are moving every couple of days and you have good charging from your tow vehicle connection then you'll be OK as long as you leave the fridge on propane. 

Even on the southern route you can run into freezing weather so you'll probably want to leave your water system winterized if/when you are at risk of getting temps down into the 20's. You can use bottled water in the trailer for drinking and food prep and still use the toilet, flushing with some bottled water there too. You'll need use campground showers in those conditions. Unless its really cold and doesn't warm up in the daytime you won't have trouble with your gray and black tanks.

Two 6V deep-cycle batteries are not "better" than a 12V deep-cycle battery, but the size the guys recommend looks to be the max capacity that will fit in the battery rack.  They are heavy, but far cheaper than a Lithium-ion battery.  I'd get a pair. 

I enjoy my home solar system.  But because of Eta, I'm at the end of my 3rd day without useful sun/charging.  I had to quit using the system, yesterday, to preserve battery voltage.  You will see that in the winter here in The South.  Solar alone may not be enough.  Your tow vehicle is supposed to be able to charge your battery and mine will keep it alive, but there is enough voltage drop to the plug at the rear, that not too much charging is going on.  A little generator would be a comfort.  My TV and sound bar only work on 120V.

I bought a small suitcase inverter generator for a song and mine has been excellent.  It will run everything in my 180, but the A/C and microwave, including a small stick vac I use and charge the battery.  It is quiet.  It weighs 20 lbs with fuel.  I got mine from Wal-mart, but HD looks to have the best price, now, $179.

http://https://www.homedepot.com/p/Sportsman-1-000-800-Watt-Gasoline-Powered-Digital-Inverter-Generator-802085/300792167 - http://https://www.homedepot.com/p/Sportsman-1-000-800-Watt-Gasoline-Powered-Digital-Inverter-Generator-802085/300792167

I will recommend using a low powered heater to break it in for 5 or 6 hours and changing the oil (ignoring the manual).  The first oil change will be nasty.  I have used it and loaned it out and it has not given any trouble.  It's not a Honda, but it's enough.  I bought it thinking I'd use it when maintaining my 'Pod, but it has been so nice, I keep finding uses. 

I think if you are on I-40 and south, you won't have to worry much about freezing.  You'll be in it with the heat on at night and early AM when the temps are lowest. 

You can buy a foam pillow to fit in the overhead vent and reduce heat loss there.  Some folks here have made window covers from foil covered bubble wrap to insulate the windows.  I'd consider that for the windows by the bed, at least.  The radiant heat loss through those windows can be uncomfortable at night. 

There's all kinds of power adapters, water filters, screens for openings and the like you may want.  I covered the stair with a store-bought piece of astro turf because my dog tore a toenail in one of the openings.  It looks nicer.  I have a fold up mat to put in front of the door.  I also put a runner carpet from the bed to the far end of the slide and another small one at the door, just to make it feel better barefoot.  And, of course, bath mats in the bathroom.  I use Command hooks for towels and a couple of pictures.  I make coffee with a Bodum pour over pot.  You may want one since you won't have 120V full time.  

You will enjoy an electric drill-driver with adapter to raise and lower the corner stabilizers.  Be sure to get a wheel lug cross and jack to change flats.  Wedges for the tires can help levelling the 'Pod. 

I LOVE my rear view camera.  You can see what's behind you and it helps when backing.  I bought a Haloview from Walmart. 

Be sure to check and replace the water heater anode.  Walmart and Ace Hardware stock them, as does every RV dealer.  They seem to be a single standard.  My original was gone last fall. 

Yes, 6V golf cart batteries are better for RV house battery applications than 12V batteries because golf cart deep cycle batteries are constructed differently. That is unless you find a 12V battery designed for deep cycle use, but those are rare. 

Battery design like everything else involves tradeofffs. In lead acid batteries the basic trade off is between cycling capacity and high current capability. That tradeoff changes the way the lead plates in the batteries are configured. As the batteries are discharged the negative plates are getting consumed and the positive plates are growing. When you recharge the revere occurs.

Deep cycle batteries like those used in golf carts have fewer thicker plates which means that they can handle deep cycling better than SLI (starting, lights, ignition) automotive batteries, which have more and thinner plates. More plates in the SLI batteries creates more surface area which allows for the high currents (hundreds of amps) required to run the strater. SLI (automotive) batteries are rarely called upon to deep cycle. 

Since you will never have a requirement for high currents like that in an rPod the SLI automotive batteries are not the best choice. The "marine" deep cycle 12V batteries are an in between compromise because they need to be designed to both start the boat engines and cycle for the boat house loads, so they're not ideal for an RV house battery either. RV applications are quite close in requirements to golf cart applications, requiring a battery to undergo relatively slow but deep charge and discharge cycles. 

The other benefit to going with two 6V batteries in series rather than 2 12V batteries in parallel is that the series connection assures that both batteries always get the same charge and discharge currents. When batteries are in parallel the charge and discharge each sees will be different due to inevitable variations in the internal resistance of the two batteries. Over time this will result in one battery getting exercised more than the other one. 

I still have much to learn about batteries but as most of you mentioned and from what I've been reading. Two 6V Deep Cycle Golf Cart batteries does appear to be a popular choice. 

This is one I was looking at, https://www.batteriesplus.com/productdetails/battery/rv/deep-cycle/6/sligc115 , but there still appears to be differences under the 6V & 12V DC GC umbrella. So I will continue to learn about these. 

I also found these 12V DC batteries, 

https://www.batteriesplus.com/productdetails/sligc12vt , 

Is AGM batteries a better call? I also will be looking into Renogy solar systems as were recommended by "podpeople" and "offgrid" I noticed 3 types on there website, AGM, GEL, Lithium-Iron. Is one more recommended the the other?

"colt" I was looking into a inverter generator as well. I've been looking into ones like you mentioned all the way up to this one https://www.harborfreight.com/3500-watt-super-quiet-inverter-generator-63584.html 

I was also contemplating a Jackery 1000w power station, https://www.amazon.com/Jackery-Portable-Explorer-Generator-Emergency/dp/B083KBKJ8Q/ref=asc_df_B083KBKJ8Q/?tag=hyprod-20&linkCode=df0&hvadid=416672338041&hvpos=&hvnetw=g&hvrand=5269818653921859646&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003516&hvtargid=pla-908516796636&psc=1&tag=&ref=&adgrpid=94717460820&hvpone=&hvptwo=&hvadid=416672338041&hvpos=&hvnetw=g&hvrand=5269818653921859646&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003516&hvtargid=pla-908516796636. That I could use a electric heater with and either use solar or the inverter generator to charge it. I will also be exploring insulation options as you mentioned and love the rear backup camera idea.

I would go with AGM (absorbed glass mat) batteries only if you are not up for maintaining your battery water level yourself. A standard flooded battery is much cheaper and less susceptible to overcharging than an AGM (or gelled electrolyte) battery.  That's because if you do over charge a flooded battery you can easily just add distilled water. But you have to be willing to take the time to check the battery water level every couple of weeks to a month and add distilled water as needed. If you can't see your way clear to do that get the AGM or gel cell batt. 

Lithium batteries are the very best you can get and are much much lighter as well. That could be important if you need the capacity and are pushing your tow vehicle tongue weight limit. Not only are they lighter but they can be cycled much deeper and tolerate many more cycles. But, they are much more expensive and require you to change your charging systems, meaning both your ac to dc converter, your tow vehicle charger, and your solar charge system if you have one. So quite a complicated mod. That will require you to either become knowledgeable enough to DIY it or hire an expert. 

re the Jackery thing, that is just a battery in a box, not a charging source like a generator or solar is. Don't waste your money. Solar is great, get a portable 100 watt or so solar kit with a charge controller. 

If you want to get a generator as well for those cloudy periods. First consideration on the generator is whether you want to be able to run the microwave and/or the air conditioner (come summer). If you do, you will need a 2000 watt plus generator at least. Lots of discussion on generators on this forum, use the search function to find them. 

Don't even think about using an electric space heater unless you have shore power. Neither solar or a generator or the jackery thing will run it, waaay too much energy. Use your propane heater when you are off grid. 

Hello and welcome! I hope you have many fun adventures and make many great memories with your RPod.

I used two 6V GC2 batteries for several years. I use a CPAP machine and the last thing I need is to run out of power. I was able to get multiple days between charges while dry camping. Now I have one 100A LiFePO4 battery. It required several other changes that you can see in my mods. It does save a lot of weight and can be put  inside since it does not generate flammable hydrogen gas. You can get deep cycle 12V batteries, but a true deep cycle 12V battery seems to be a rare thing. Most of the batteries are hybrid starting/deep cycle marine batteries. While they may work, they won't have the capacity that a pair of 6V GC2 batteries will have unless the 12V one is as large and heavy as the two 6V batteries. I like my less than 30 lb LiFePO4 battery over the 120 lbs of lead-acid batteries I used to carry.

My new lithium cells arrived yesterday (LiFePO4) and I'll be reviewing his BMS comparisons. Just to show I go to his site as well.

http://www.youtube.com/c/WillProwse/playlists - http://www.youtube.com/c/WillProwse/playlists