"This is what I've been telling everyone in this string.
If you read it from the start,"
I am not seeing all the posts in this thread for some reason. A new one ( 18th supposedly) just came in but not showing on mine. I have 14 replies showing out of 18 listed.
Anyway, your 12.9/12.8 is normal for the controller before it starts controlling--it lets the battery voltage pass right through to the panels, so "panel voltage" is the same as "battery voltage".
Your battery will not recover to good health by just leaving it on that solar from now on. It needs a major "recovery" involving desulphation at high voltage (to 16v) and that solar can't do that.
You can use the solar to do it if you by-pass the controller and go "panel-direct" manually but it is procedure that takes a lot of your time and attention and requires good sunny days. Also needs the battery disconnected from RV 12v systems, so you need another 12v source to run the rig meanwhile.
