Just an FYI...LA batteries
I cannot find, for the life of me, a thread from a long time ago when the discussions of 3 stage charges/battery life, etc. was just genning up. But in that thread, I had just installed two new group 29 Interstates, an Iota 3 stage charger and a Trimetric monitor, a BatteryMinder desulfator and stated that I'd let folks know when the batteries died.
So the answer is 5.5 years. The batteries plugged along with close to full capacity (Ah) for about 5 years and slowly started to drop off, but by no more than 10%. Then suddenly 2 cells of one battery started consuming large quantities of water and the capacity dropped to about 50%.
So, in the other currently active thread concerning AGMs and the possibility of well fed batteries lasting 6 - 8 years, I would say that's entirely probable.
BTW, I am very pleased with 5 1/2 years out of (mass market average brand) LA batteries.
Just an FYI for inquiring minds.
"If the women don't find you handsome, they should at least find you handy." - Red Green