Odyssey batteries provide excellent documentation
on how to recharge their batteries when deeply cycled.
It is not just a 'apply any charging source anytime and happy cycling'
It is an' If you deeply cycle this battery, it requires 40 amps per 100 AH of battery capacity/ 40 amps until 14.7v is reached, then 14.7v is to be held for 4 hours.
They are the Super greedy AGM
. They are not a good low and slow recharge battery, not a good solar
only recharge battery when deeply cycled.
One cannot expect them to last when their charging parameters are not met.
So can you feed them 40 amps per 100AH of capacity? That is a lot of amps.
Can you hold them at 14.7v for 4 hours? Most charging sources cannnot/will not.
The extreme price
of Odyssey batteries does not make them immune to chronic undercharging or improper recharging, and if anything AGMS are less resilient when their charging demands are not catered to, compared to flooded deep cycle batteries.
I deeply cycle a 90 AH Northstar AGM battery, whose design and claims as to performance is very similar to Odyssey. If I allow 200 watts of solar to replenish this battery, day after day, to full charge. Meaning is brought upto and held at 14.46v until amps taper to 0.425amps, on the fifth night of a solar only recharge, I notice that the voltage held for the same amp hours removed has dropped drastically compared to the first night.
The Next day i will apply my 40 amp adjustable voltage power supply from its most depleted state, until 14.46v is reached and held long enough for amps to taper to 0.425a.
This restores lost
performance. Voltage held under load returns, the ability of the battery to smack my engine
to life super quickly is returned
I know the low and slow trickle charge crowd is still vocal in the lead acid battery world, but AGMS, when deeply cycled, crave high amp recharges. It is not that they 'can' accept huge charging amps, it is a requirement. Some AGM brands, will say to limit bulk amps to no more than 0.3c, 30 amps per 100Ah of capacity. Still, they benefit from currents approaching this maximum
To the OP, I would recommend being able to recharge the battery's individually, at a high rate until they reach 14.7v, and hold them there for ~ 4 hours.
0.4c is 40 amps per 100AH of capacity.
This might allow you to get back some lost
capacity, or it could be too little, too late.
Lifeline AGM recommends 0.2c minimum when deeply cycled.
Voltage is certainly important, but with AGMS initial Amps applied from a depleted state is also Key to their longevity in a deep cycle application.
Increase the diameter of your cabling from alternator
to battery, and aim a fan at the alternator. This should help the next battery bank last longer.
AGMS are great, when their high amp recharge requirements can be met every so many deep cycles. If not, the end user will not get their money's worth