Newb with 21G Battle Born Upgrade Questions!

[Zeke27G]

How's it going Grand Design gang?

Purchased a 2019 21G Series a couple months ago from the original owners who only used it once! We just took it on our maiden voyage last weekend to the desert after upgrading the China bomb Westlake tires to some Goodyear Endurance tires, with a TST-507 TPMS connected. Everything went well, except for the last night when the original lead-acid Interstate batter went dead on us and left us with no 12V power. So now we're looking to go the Battle Born route, but I have some questions for 21G owners who have done the same.

How many Battle Born batteries would I need? We boondock about 50% of the time and it's never for more than 4 or 5 nights. We have the onboard generator as well as a Honda EU2000 that we use when we're running things like our Camp Chef Pursuit smoker for several hours. So our batteries would be getting re-charged daily.

Also, are the Battle Born batteries with the built in heating unit worth the extra coin?

Lastly, I was planning on mounting the battery(ies) in some sort of trailer tongue tool/storage box behind the propane bottles. If any of you have done that sorta mod, can you recommend which brand of storage box worked best?

Thank you so much!