We are full time living aboard for six years now. We have done the Great Loop and have anchored extensively. We have eight golf car FLA batteries, 920ah. They are now five years old and still at 97% capacity as determined by a Balmar SG200. (YES, the SG200 works for me.) I expect my batteries will last at least 3 more years before their capacity is diminished enough to prompt replacement. The 460ah of useable juice is more than sufficient for our use case. I can replace the FLA bank with Trojan T-105s for about $1,200 and readily available in most places. So, in my case, for the mere price of $1,200 I can get 11 years, 3+8 of juice, perhaps more. Why would I invest in lithium not to mention the additional infrastructure costs? Extend that to another cycle, another $1,200 gets me to the age of 90. Will I live that long? Demographics say no. If I do, will I choose to be on the water or even be able to do so? Not likely. Lithium makes absolutely no sense to this boater, cost or utility-wise, not even close. Now, when comparing to the cost of AGMs, perhaps the numbers work for some folks. But, for me, AGMs do nothing that FLAs don't do just as well. I'll be sticking with FLA and maybe in three years dropping in a new set of Trojans and no need of any new infrastructure.