Everything (both batteries, charger) is out of the boat, in the shop. There is no outside interference from electronics. The charger has successfully shown it can charge each battery individually.
As stated earlier, I let them charge parallel for about 24 hours. This morning, they were still "showing" charging. I just disconnected them and reconnected them individually. Both went instantly to maintenance mode.
FWIW, when the charger is live with no batteries, it shows maintenance mode.
Rich, I have a larger Schumacher, but it is an antique I can't trust and I ain't bringing that beast into this equation. :?
And thanks to you guys for trying to help AND your patience!
Last night I had the charger wires hooked positive to battery "A" and negative to battery "B". It is one big 12v, so this should work. It always has in the past. Like I said, this morning, they were still "showing" charging.
I just hooked the charger to terminals on one battery, they're parallel, and I
FINALLY have maintenance mode showing.
Now I'm going to hook a receptacle to the trolling motor so that is unplugged from now on while charging and I am going back with 8 gauge wire.
This has been a learning experience and a test in patience.....