I think the thing to think about is Costco and Sam's Club have bought different batteries over the years. I think the 6 v GC batteries I bought from Sam's Club in 2007 are Duracell's. They are still working fine and I dry camp 95% of the time. I was looking to eventually replace them with Costco batteries because I am a Costco member and have read the same reviews and posts on this forum about the premature failure of these batteries. In addition I have gone through 3 12v starting Costco batteries in 3 years all under warranty. Also replaced 3 in my daughters car. The tech said they were all purchased from China and there were a lot of returns. Sam's Club may have the same issue. I would look at Batteries Plus they sell Duracell's and Crown batteries for not much more than Costco. I am very happy with my the performance of my 14 year old Sam's Club batteries but would be reluctant to buy new ones there or Costco unless I new who made the batteries and to what specs. And no I don't keep my batteries on float charge. When not camping I let them self discharge to 80% SOC then recharge to 100%,off topic but interesting discussion.
