Hi All,
I have an ESS comprising of:
ET340 connected to three phase grid but set to single phase and only using L1
Cerbo GX
4x MultiPlus-II in parallel single phase
2x BlueSolar MPPT 250/100
40kwh of battery connected to Lynx power in
The whole property is running off AC Out 1, I would normally not be using the ET340 in this case but I thought I would add it as the grid meter to fix the problem.
My problem is that no matter what I do the system backfeeds power to the grid, I can make the Grid setpoint higher to counteract the back feeding (currently its set to 180w) but the amount of backfeeding is around 10 to 15% of the load so when there is a high load it overcomes my grid set point and starts back feeding again. It back feeds anytime of the day, solar available or not. When I initially setup single phase, the MP-IIs were set as the grid meter.
When 3 of these inverters were in 3 phase configuration the grid setpoint was at 30w and back feeding was not an issue, the system worked as expected. Unfortunately one of the phases became unstable and the MP-II would no longer accept the grid. The utility has been out twice to solve the problem but thus far we can't get a stable sync to the grid. Hence why I resorted to changing to single phase.
I suspect that one of the MP-IIs is somehow faulty, it seems to me like the internal CT is "leaking" the more current there is the bigger the leak becomes. I just wanted to confirm that this is possible before taking each MP-II out in turn to see if one is the culprit.
