Optima's, besides their recent quality reports, were never a great choice for a deep cycle battery as their capacity is 25 to 33% less due to the spiral cell design. CCA is not capacity.
Odyssey/ Sears Die Hard platinum are excellent AGM batteries, but when cycled deeply, they want to be fed a 40% charging rate until 14.7v is reached, and then hold 14.7 for 4 hours before reverting to float at 13.7.
So the group 31 Odyssey want 40 amps initial bulk current minimum, when cycled deeply to perform properly on the next cycle at full capacity/energy density. Not good for a primarily solar recharged system.
Other AGM batteries do not require such huge recharging currents, full river wants 20%. Lifeline says feed them as much as you possibly can at no more than 14.5v, and this could be 400 amps on a 100 amp hour battery, or more.
Many Asian AGM batteries say not to exceed 20% charge rate, probably more suitable for those who use solar as the main charging source, and whose alternator charging circuit is not seriously upgraded.
Sears die hard gold AGM is a rebadged deka intimidator series that says no more than 14.5 and no more than 20% and these are kinder to one's budget. My alternator will do 14.9v though, so I ruled these out.
While seeking a perfect charging regimen for any battery is hardly manditory, with AGM's and their greater investment, one should make more effort to meet the manufacturer recommendations as to charging amps and voltages to get the most out of their investment.
Also one should check the maximum voltages their alternator will feed the battery. If it exceeds the manufacturer recommendations, then find an AGM battery which can handle your system's maximum voltage, or meet the minimum acceptance voltage.
But you can also just slap any AGM in there and then it just hurts a little more when it fails earlier than it would if it were fed the manufacturer recommended recharge regimen.
