Thanks for all the replies. I have a few responses to comments made throughout these posts.
- To be clear, I am comparing 2 6V vs 2 12 v not a single 12v. I have room for either on my tongue
- The Costco option does not appear to be an option for me. My Costco no longer carries them. Said they can order but when you read on-line the reviews are horrible for that Interstate 6V battery.
- I have not Checked wall-mart or auto parts stores. Where I have found 6V in stock local to me was a battery plus location selling Energizer, a golf cart company selling Trojan, and an interstate store. The price ranges for those 3 locations for a single 6V was $128 for Energizer / Interstate up to $200+ for trojan. NAPA online is $120. I am just not seeing anything below that. I was comparing that to a 90 Ah 12V Interstate for $120 each. This is where I came up with similar AH for similar money with 2 12V . 180 Ah with 12V vs 240Ah with 6V. By the way, we are fine paying a little more, I just wanted to make sure I was not missing something since I read so many posts talking about <$100 6V batteries.
I had my mind set on going with 6V this time around but was just surprised on the prices as I had always head they are cheaper. And, I was very surprised to see such terrible reviews on the Costco website for the Interstate 6V. I do have a tendency to discharge the battery quite far when we boondock, especially if we have to run the furnace, so points made in this thread of deeper discharge might be the important focus point for our situation
Thanks again everyone. I know this topic is beating a dead horse, but it was the Value / Cost angle I wanted to look at here.