Originally Posted by HMoll
I never had lead acid or lead. When I bought my boat, and studied a bit, aside from cost, AGM was a no brainer. They lasted four years, and my use was very irregular. Last year, I upsized my battery bank to (7) 105Ah battery bank, AGM. I run a 10,000BTU air conditioner with it. Love it, no genset. Turns out that my engine is quieter than my single-cylinder genset too. Another advantage is that AGMs are sealed, zero maintenance and zero gas emmissions from what I have read. Good AGM bank and large alternator. More than enough for your refrigeration. Do the numbers. Good luck!
AGM IS.......lead acid......... They can also vent gas if over charged, and when they do, the lost electrolyte can not be replaced.
If your bank of AGM batteries is made by Lifeline they are not maintenance free and need to be equalized occasionally, or as Lifeline calls it "conditioned", at 15.5V temp compensated for about 8 hours, especially if you are a cruiser.
My experiences with AGM, to summarize, are that:
They cost a lot more
Have shorter cycle life
Accept more current than wet lead acid
When they fail they tend to fail with little to no warning
Need to be charged to 100% SOC as often as possible
My experiences & thoughts.....
AGM's Making The Choice (LINK)