Excuse me if this has already been answered but I’m looking to see if anyone has done any testing with frequency watt adjustment on load side when grid is down and PV is generating more power than needed. Do the iq7s have issue with anti islanding detection? I’m thinking about switching from outback skybox but i don’t want to rewire the whole thing so ac coupled solar will be on the critical loads side.
18kpv with iq7+ on load side?
- Thread starter goldserve
- Start date
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
I have not personally tried the AC coupling the IQ7s to the 18Kpv, but it is supposed to work. The instructions say to hook the AC from the IQ7s to the Gen port to do it. If the system does not need the energy from the IQ7s it will start raising the frequency to throttle the IQ7s.
Note that when connected to the grid, the grid is driving the frequency, not the 18Kpv. Consequently, while connected to the grid the 18Kpv is not controlling the IQ7s.... the grid is. The primary implication of this is that when connected to the grid, any energy not used by the loads or the battery charger will be exported to the grid.
Understood how everything works and that’s how it works on my outback skybox when it comes to ongrid and who’s driving the off grid critical loads frequency. I am asking because I don’t want to reconfigure my electrical as the iq7 already back feeds the critical loads panel and when ongrid, the energy is used to support charging, main loads panel and then sold back to grid.
I hope I can set an export limit and I will have around equal in DC pv string so it can modulate that is needed to control export.
I hope I can set an export limit and I will have around equal in DC pv string so it can modulate that is needed to control export.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Ohh. Sorry. I misunderstood.
The instructions call for feeding it through the Gen port and I noticed that the 18Kpv has an error it throws if it is seeing energy come in from the load port.
I don't have a solid understanding of the internals of the 18Kpv so I don't know if there is something fundamental that makes it not want to see power coming in from the load port. The only two reasons I can think of for insisting on the energy coming from the gen port and throwing an error if it comes from the load port are:
1) There is some case where it uses the relay on the gen port to disconnect the AC-coupled inverters. (I have no idea when that would be)
2) It has current sensors on the gen port and uses that information as part of the overall system control. (again, I am not sure what that would be).
Feeding through the Gen port seems common to a lot of hybrid inverters 18Kpv, Solark & Schneider all do it.
Sorry, I can't be more helpful.
I guess that works up to the point where the AC coupled is producing more than the battery and load. At that point even if it cuts the DC coupled input to zero, the excess is going to go to the grid.
It’s been asked, by me, in another thread, a week or two ago. No answers yet.
Where is this documented? This suggests that the inverter does not support AC coupling on the load side, only through the gen port. I’d be very interested in the source of this info. And some definitive answer from Signature/EG4 would be helpful.
Similar threads
