Hi all, My system is 1.8Kw panels with enphase IQ microinverters and enphase envoy controller. I have the enphase set to no export with two CTs on the grid input. That works fine with no issues.
The system has to be AC coupled, I added a Multiplus 48/3000/35-50, 220V and used a 32A Victron autotransformer to get the split phase system to work properly. also have 8 x 6v GNB Marathon Element AGM batteries.
My issues with the system are:
*Optimized Without "Batterylife" mode, the charger doesn't reset after a discharge to minimum SOC, so effectively stays all the time to the latest status it had(eventually remains in float forever), Here in my region I don't like Batterylife changing the "active SOC limit" on daily basis because some days are cloudier than others. But cant use it without Batterylife, because the problem with charging.
*The Enphase no export limit seems to be around 50W, this cant be changed, so I had set the ESS "Grid setpoint" to 120W. During day time, after the ESS detects loads getting under the grid setpoint, it does start charging, but immediately enters self consumption any time the loads are greater than panel generation. This keeps interrupting the charge on cloudy days, there is some claims that is better to charge the batteries to 100% before using them on the next cycle.
The solution could be using a schedule to set the daytime as charge only, not allowing self consumption to kick in. And also for the inverter to use the battery when the tariffs are higher, or to allow the batteries to rest in float mode for a while(there is also claims on this to be good for the batteries). Basically something that tells the system when it is allowed to kick in the inverter.
A work around I found is setting the "Maximum inverter power" to 0W every night after battery is discharged to "Minimum SOC", with "Limit inverter power" enabled. Then I have to set it back up for the inverter to start back. But I see no reason why couldn't be automated.
*When the grid is gone the Enphase envoy seems to command the microinverters to shut down, because it does detect 0 Watts on the grid input. I had to manually change the enphase profile to allow export, for them to come back to life. I plan to test a relay that activates a load to trigger the current transformers to report a fixed load above the grid setpoint on the envoy. I think I have to wrap several turns around the CTs to achieve this with minimum load.
Regards
Alex V.
DR
