Congrats! We saw a big difference when we went to 2 golf cart batteries from the singe OEM battery. Not hard to do other than the weight, they are hefty, about 60 lbs each. Nice bump in capacity. They have boxes that are made for the 6-volt sizes.
ie. https://allbatterysalesandservice.com/battery/battery-boxes when I did mine I just reused the OEM ventilation holes and hose.
The only warning is to make sure to keep the water levels up, that's usually what kills them if the water gets below the plates. Doesn't take much, just take a look every couple weeks and add as needed distilled water.

I have two six volt batteries and they work extremely well for off grid camping. With minor use they will last three days pretty easily. With heavy use (watching TV for 8-10 hours), I draw mine down to about 85% state of charge every day. I run the generator for about an hour and it brings them back up to the high 90s or 100%.

I would also consider getting a quality battery monitor that uses a shunt. It is important to know what the batteries state of charge is, if you go below 50% you will damage them.

My battery monitor tells me the state of charge in %. It is very helpful. I use the Victron BMV 700.

https://www.amazon.com/Victron-Energy-Battery-Monitor-BMV-700/dp/B01BVQR0V8

Hi, Brian:

X 2 on the other suggestions on this great forum. I might add that, while you’re at it, you might consider getting four lead acid 6-volt batteries if you have the space for them. They are relatively cheap -especially compared to the Battle Borns we’re all lusting after - and it’s easy to build your box out of particle board. For moving the batteries around, you will NEED a strap-type handle. With four batteries, you can double the amount of time before you have to fire up the Honda. Best wishes with whatever you decide and Happy Holidays to everyone!

Phil

I converted over to the 6 volt setup. Worked well on our Wildcat by Forest River. Purchased a 6 volt battery box that holds 2 golf cart batteries. Removed the old battery box installed the new one in its place - connected the venting and adjusted some wiring. All Good!!

Hi Brian,

I have upgraded from two 6 volt golf cart batteries to three of these ( Valence Lithium Battery U27-12XP | 12V 138AH 1.766 kWh ) . One battery weighs 21 lbs less than two golf cart batteries. and has 38AH more usable power. Three of them have 414AH usable power. I am going to add one more for a total 552AH. These are by far the best price out there for Lithium Iron Phosphate (LiFePO4). The company is very well known world wide. And has been building these batteries since 2005. You can mount these inside under your bed like us if you want. No need to vent them. Can mount in any position, upright, on their side, upside down. Nothing to spill or drain out. Very convenient. And the advantage to mounting under your bed is when boon docking in cold weather. You can keep the batteries about 32 F. And under 112 F in summer months.

Hi Brian,

I'm fairly certain you won't be happy with having just one battery if you plan to do any dry camping. I have a small 5th wheel trailer. The batteries are located in what used to be the generator compartment, and as a result there is no access to the tops of the batteries. I now use two AGM 6-volt golf cart 8AGC2 sealed lead-acid batteries. They are more expensive than regular batteries, but it is nice not to have to remove the batteries to check water level. I got about 8 years of life out of my last big 12-volt 8A8D AGM battery, but that thing is a 175-pound beast and just too heavy to deal with. The two 6-volt golf cart batteries are more manageable. AGM batteries are more finicky about charge level, and I'm careful to not let the batteries drain down below about 50% of charge. I replaced the OEM battery charger with an Iota unit and module specifically designed for the AGM batteries. I also have a 140 watt solar panel on the roof. I also carry a 1200 watt inverter generator, but rarely need to use it unless the weather socks in for more than a few days. My wife and I are snow birds, spending a couple of months in Arizona in the winter, dry-camping some of the time.

It'll be great when the new lithium iron phosphate RV batteries fall within my price range! :-)

Safe travels!

Rick, the way battery technology is going there'll be something better than Lithium soon enough. We will never see lithium come down to much on price, and that's account of a lot of factors. Do some research and you'll see a lot is going on with batteries account of the electric cars. A lot of research is taking place to find a better battery than lithium account of it not being very recyclable.
I'm here in Miami and have found a fire fly dealer. Am looking to upgrade my trojans(close to 6yrs old) to them. I had to shore up my front compartment where I use 8 6 volts for my solar setup that was installed by MobileHomestead Solar Service. All that weight finally got to the 3 little screws that held the pan to the front support.

Researched back in my folders and found where I purchased my original Trojan T-105's 09/2014. After 5 yrs and a lot of service out of the those ole babies I found some new T-105 RE;s for $155. Not bad, and it beat $700-$900 a battery. Got them replaced and charged them up now time to equalize them babies.