Is this a simple single bank charger? I find it odd it will charge 2 batteries at same time if it is, unless both batteries are physically connected together, or the charger is a 2 bank. If both batteries are indeed tied together, then there is no separation of the 2.

Where are the chargers leads connected?

Yeah its a simple trickle charger...
I have to go look into this further I guess, I connected the charger's leads to the cable you plug into the boat's fuse panel.

Batt 1 was fully charged and Batt 2 was not, however batt 2 was half charged, when I checked yesterday.

I think in the fall I am just going to manually put 2 trickle chargers on each battery using alligator clips, because I don't know how this battery cable that plugs into the fusepanel is wired...

Jezuz at this point it's easier to just buy new batteries every year...

disconnect and take them out or charge them and or just disconnect Ive been on the same batteries for three years. No need to reinvent the wheel on boat batteries

I do use two separate "float" chargers, one on each battery connected directly. I don't think you can successfully "float" multiple batteries with one charger. I buy the chargers at Ace Hardware for about $25 each (keep one on my generator and the Corvette). Much less expensive than replacing batteries!