Is it imperative to have AGM batteries with a solar set-up? Why? Could you not just use 2 6v batteries (not AGM's)? Do they last longer? How much and are they really worth the price difference?
AGM batteries become standard in latest years of Mercedes. When flooded batteries by Varta could last 10, 13, even 17 years, the owners of AGM seldom report more than 5 years before they need to break the bank for a new one. My flooded Sam's batteries lasted 12 years, neglected for long months in storage.