Battery Life

Good time to upgrade to LiFePO4 The cost is getting down on those. Check out Battle Born for RV use..

Thanks,
I Did let them sit I believe too long without being on the charger. I took them out prior to the coach going to repair shop after an accident. So most likely I may have done it to myself. OH Well, it is what it is. I did speak with a person at Batteries Plus, Actually have right at 5 full years of service out of them. for me, was good as used to cost me an average of about $100 each for about 14 months, $7.5 per month. With the cost of these, $240 each, about $4 per month without the need for filling, smell etc. I'm good with that. anyhow, that is my story and i am sticking to it.

I had 8D AGM's so that might be different but my first set lasted 10 years before I felt they were under performing and the 2nd set were over 6 years old when I sold the coach and they were still doing just fine. Be sure your charger (or inverter/charger) is setup for proper charging of AGM's as they have a different profile from wet cell or sealed batteries.

At 5 years it may be end of life.
The average life for Flooded wet is 7-10 years
The Brag is AGM's last longer and I will admit sometimes they do (saw one hit 12)
But for the most part they do not. No sealed lead acid does.

5 years sounds like it might just be "end of life"

On the other hand.. I gather you let it sit for quite some time.. Between self discharge and parasitic draw (Things that never turn off) the batteries were likely run down past the point of "not likely to return" ... Starting batteries need to be kept fairly full 80-90 percent or more.. MARINE/deep cycle also sold as MARINE/rv, are starting batteries with lip service to "deep cycle" they can go a bit lower, say 75%.. True DEEP CYCLE well the common wisdom is 50% and they stand a much better chance of recovery from an OH C@@@ level discharge (like down to 20%) Note I said Chance. No guarantee.. Kind of like sticking a dollar in the one arm bandit in Vegas.

so it may be they just aged out or it may be they were run down too far.

Yep, I know I need two new ones. I wouldn't do it any other way. I will give the one good one to my son-in-law and he can finish it off. I was just curious about the life expectancy and how well these lasted.

2.2 volts per cell, 13.2 volts at full charge on a good battery.
10.5 volts tells me that one cell is bad. The working battery holds about 2.08 volts per cell and 5 good cells x 2.08 = 10.42 volts.
Two new batteries are in need.