I thought I knew the answer but my meter says otherwise..........

The new boat was billed to have two group 31 batteries, I was impressed that a builder would plan for such a good thing. Prior to the purchase I asked the broker how old the current batteries were, he questioned the owner who said 2-3 years. Not brand new but not bad figuring the boat was "professionally maintained" and the batteries were removed and stored for the winter by his mechanic.

Upon purchase I looked behind a panel in the aft cabin and sure enough, two very large battery boxes all strapped in and good to go. Fast forward to two weeks ago, we were wrapping up winterization and covering so I climbed back in the aft cabin to remove the batteries and find two group 24's instead, rattling around in nice big battery boxes. Another thing on the list of things that pissed me off about this. I took them home, down into my workshop where all batteries spend the winter attached to maintainers until spring. Wellll, I have been busy until this past weekend and did not get them hooked up. I cleared the space, put the batteries up on the side bench and as is normal before storage, popped the caps to top up the water. The professionally maintained batteries were pretty much dry, I could not see the water level below the top of the plates. I didn't bother to fill them or hook up the maintainers. That's that I told the Admiral, two new batteries come spring, she just shook her head. A day later I went back and just for the heck of it checked them with my meter......13.1 volts? I expected dead as a doornail? Each battery took a little over a quart of distilled water and hooked up to the maintainers are registering about 13.5 volts.

Never dealt with this before, should I just cough up a few more boat units and pick up some new group 31's or is it possible to continue using these?