Hello,
I’m interested in the integration of MPII + SE (scheme), because after reading various articles and guides, I’m still confused about it.
This is just a preliminary design,it’s not final yet, and I’m not sure if it will be possible to feed excess energy back into the grid.
,because from what I’ve read on various forums, some say yes and some say no, Also, some mention using a different contact than K1. Or is it enough to just set the frequency (from step 3 onwards in the manual)?
Your battery bank needs to be able to sink power if a large load drops off during high production. Otherwise components get damaged.
Yes, if it is needed for zero feed in. That is mentioned a few times in the link in the guide.
Once you are done with the SunSpec setup you can re-configure RS485-1 for your SolarEdge Grid meter. The SolarEdge meter is still required for a zero export setup. The SunSpec setting will remain in the memory of the SolarEdge.
No, there has to be other methods put in place because frequency shifting doesn’t work on grid.
Yes, I know that it’s in the manual, I just wasn’t sure if it’s also for the my scheme when everything is on ac-out because the manual has schemes where the load is on AC-IN and AC-OUT
And the multiplus can’t fully control the SE via modbus? Or is this setting like a fuse?
I’m running a similiar installation: 3x MPII 5000 with 6xPylontech US5000, SE10k. My installation has a switch that I can use to run all loads and the PV inverter either on ACin or ACout1.
What I don’t understand is why the MPII has to be able to control the SE in a setting, in which grid is present and SE is on ACin. Maybe @lxonline can help?
While grid is present, any excess from SE can be “dumped” to grid. If grid is lost, SE will immediatley stop producing due to SE’s internal safeguards (“NA-Schutz”).
When switching over, loads and SE are connected to ACout1. I understand that frequency shifting is not possible when all loads and the PV inverter are on ACout1 and grid is present, due to the MPII’s internal relay connecting ACin and ACout1. Also, the MPII can’t control the SE in any other way than via frequency shifting.
However, when grid is lost, the MPII will immediately increase the frequency on ACout1 to pre-set values - in may case 51.5hz - and SE will stop production. I just tested this yesterday and it works fine.
Are there safety concerns i’m negleting? Wanna be rather safe than sorry
So in my setup the SE will always be on AC-OUT. That means I just need to configure, according to the manual: Frequency Shifting, ESS assistance (Frequency), and SE inverter monitoring, right? There’s no need for any additional APS wiring or energymeter?,because with 3xMP II + MPPT and every loads on AC out, energymeter is not needed.
So when the grid goes down, the SE will stop producing and the loads will be powered by the batteries? Or, let’s say the batteries are at 50% and it’s sunny day— will the loads be powered by the SE and the rest from the batteries, or second case will the SE supply the loads and the rest from pannels go into the batteries?
The official victron documentation states that you either need an external relay or have to use the internal programmable relay K1. This seems to be necessary to detect a grid failure.
Also the documentation states: " In addition to the settings above it is important to contact SolarEdge Support to change a parameter in the backend to allow the frequency shifting with APS mode."
A while ago I chatted with SolarEdge support regarding the above mentioned requirement and got the information that there are no parameters that need to be changed on the SolarEdge side.
Currently, I don’t use an external relay or the K1 relay. I just tested the system by connecting all loads and the SolarEdge inverter on ACout1 and then disconnected everything from grid.
The MP II immediately increased frequency on ACout1 and the Solaredge inverter stopped production. All loads were powered by the batteries, no interruptions occured.
After a little while (1-2 minutes), the frequency dropped and SolarEdge restarted production. The loads were powered by batteries and SolarEdge production. After SolarEdge production exceeded loads, the batteries were charged with excess solar from SolarEdge.
After decreasing the current charge limit in DVCC settings, MP II increased frequency again to lower SolarEdge production. Afterwards I reconnected grid and - after hearing the relays inside MP II clicking - grid connection was reestablished and everything went back to “normal”.
I concluded that frequency shifting works to control SolarEdge.
I’m unsure however if this is a safe way to operate the system as it does not follow the official documentation. So I switched back to gird-parallel operations (all loads and SolarEdge on ACin).
I’d be very grateful if someone from Victron could comment on my above observations!
