Have you tried calling Xantrex? I have found them fairly helpful.
First my apologies because I am not on my boat and (gulp, hate to say this) on pain medication for my back so I am a bit loopy. I probably should not even be trying to help you as I may have you burn the boat down!!!!
Ok, here goes:
The top line on the prosine, IIRC, is battery. It is current voltage, then amount of amps out, then battery temperature.
THe second line is AC/inverter., followed by the AC out.
The prosine is a smart unit - but must be programmed. Did you program it correctly with your battery type and bank size? Did you program the breaker size?
The AC coming into your boat must go directly to the inverter/charger
. Did you do this?
Nothing before it!! No shortcuts unless to breakers/fuses switches... but no other loads. IT IS A DIRECT RUN from shore. Nothing else leads in. Nothing else leads away. Think of it as the distribution panel for your boat that knows what is going in and what is going out. Since you have programmed your breaker, assuming it is 30amps, it knows not to exceed that - but will also maximize that. It wil automatically keep the inverter off when you are plugged in. When not plugged in, it will turn on the inverter when neccessary (assuming you have it switched on).
Are you sure you do not have your inverter back feeding your charger? THis happens if you have the 110 going out of the panel, back into the ac-in leg, that leads back to the inverter/charger.
When the prosine needs to invert and pull of the batteries, it will only do it when there is no AC power feed. And IIRC, the 2.0 is a constant run 2.0 but will actually exceed the 2kw for short periods of time. THus, I cannot see why you are having a V problem. My guess is a poor connection or insufficient wire size. As I said, 4/0 is the absolute minimum because of the potential for the large upfront draw. They really want you to put in 250-350 mcm. Let's see, 4/0 is about the size of my thumb - maybe bigger. It typically has to be ordered. Few West Marines actually carry it in stock.
I know I keep harping on that - but just be sure you have the proper wire size. Make sure you have very good battery connections.
Those are my very dissorganized, Vicodin thoughts. Many apologies if it is a little hard to follow. Just make sure:
1) You have 4/0 (or bigger wire).
2) Good connections.
3) Direct leads to the charger/inverter from the dock
with NO loads before it and NOTHING leading back into it.
4) No lead from the inverter (like a 110 run/leg) back into the charger.
I do not know if I have helped. Good luck. Let us know how it turns out.