How to test working capacity of battery: not technical

If AH consumed to ~50% and measuring voltage were an accurate method of determining capacity, my 90AH rated AGM battery would actually be around 115 to 120AH capacity.

Seems the AGMs do well down to 12.2v and then quickly fall after that.

Either way it looks like you batteries are still healthy.

The real test would be comparing results after 50+ more cycles and using this same test, and if one were to have data from when the batteries were new as well