Hello, I am hoping that someone could help me with an issue with my off grid setup.
The system uses x2 Quattros 10kva set up as 2 phase 180 degrees apart.
I use solar charge controllers to charge lithium batteries, 48volt system.
There is nothing else connected to system as in no ac input.
I do not use the chargers on the inverters, they are switched off.
Outputs are on ac1
Everything works fine under normal use. Solar chargers do their job, everything works ok.
A problem exists when I switch on a separate solar system on one of the lines.
The other system is 5kva with an inverter, use to be for grid tie.
Things look ok to start with initially, The load on corresponding inverter drops off as the load is being supplied by the other system all looks good.Then the voltage starts to go up far in excess of the battery peak voltage settings which is 57.7. The voltage climes to over 60v and the overvoltage alarms going off.
To double check, I switch off the solar arrays to make sure there is no problem there and the problem persists. I then turn off the separate solar system and voltage starts to come back to what it should be. So there is definitly power coming back through the inverter unregulated into my batteries some how.
The charge function on inverters are turned off.
Its a 240volt system and when the other solar array comes on line the voltage on that line is around 251volts.
As far as I can see somehow the higher line voltage is causing a feedback into batteries in an unregulated way.
Can anyone please give me an idea as to why this is occurring and how it could be fixed, am I missing something or can I just not use the other system. Or can I even increase the Quattros inverter output to match or surpass the other inverter voltage.
Thanks
