When my 4 solar panels are all full capacity (bright, sunny day), and the batteries are relatively full, the voltage across most of the batteries (reading either individually, or in groups/parallel) can read 15+ volts, and my inverter shuts down. If I turn off the solar panels (on the controller), the batteries will go down to reading about 12.8 - 13.4 volts. As soon as I turn on the solar again, the batteries go back up to 15+ This is both confusing, and also I wonder how can I ever truly charge (top) my batteries.
I'm attaching my wiring diagram (excuse the rough .pps format - I don't have any fancy wiring diagram tools), with the battery and solar panel specs on the second slide.
My question is - it seems I cannot get to the max charging capacity with this set up. Once the batteries get CLOSE to full charge (13.4, say), the voltage recorded on the batteries goes above 15.1 when charging, and I have to stop charging so I can use the inverter. Ironically, once the inverter shuts down, the battery voltage will go even higher (if the solar panels are connected).
I get that there is a difference in the voltage reading on the batteries when they're charging, but the difference in the charging voltage vs. resting (float) voltage seems unusually high.
Also, I thought my battery charge controller was supposed to take care of all of this. When I call Morningstar (I now own 3 Morningstar controllers), they are NO help - in fact, their tech guys have been pretty evasive (well, except for one, who cleared up a question I had about wiring the battery sensor, but did not end up providing a solution/answer to the battery over (or under?) charging issue). It's like they don't want the little guys (like me) getting into solar (?) go figure.
Can anyone help me understand what's going on, and how to fix it?