The trimetric has an Ammeter, no?
How many amps were flowing? Some PD amperage will go to feeding DC loads, the rest should go into the battery and be read as +48.X amps or so.
Takes a while for voltage to rise when the batteries are at 55%
It takes my single 90AH Northstar AGM when drained to 50%, about 35 minutes at 38+ amps before reaching near 14.5v, at which point amps taper.
When amps taper to 0.4a, at 14.5v on this battery, I consider the battery fully charged.
Sometimes my battery monitor agrees, often it is 1 or 2AH out and that 1 or 2Ah can take one or 2 hours more at absorption voltage before amps taper to 0.4 or less.
Blindly believing the trimetric is not wise. they drift with accumulated cycles. Best thing to do is reset them when specific gravity is maxed out, and lower the total capacity as the batteries age, or watch the AH from full display instead of the % remaining.
When the batteries lose capacity, and the trimetric reads 55%, the batteries could actually be well below 50% as they are no longer ~160Ah, but perhaps 140, and might not have started the discharge cycle at a true 100%.
When these group 24's fail, 6v GC-2s are real deep cycle batteries and nearly the same footprint, just taller and will yield 2x the total cycle life, all factors being equal.
But since you will have ~65 more AH total capacity with them, the depth of discharge will be less, so they will last even longer.
