Title: Experience with SolarEdge NX20K and Nexis Battery?
Hello everyone
I am currently testing OpenEMS on a Raspberry Pi 5 and trying to understand whether it could later manage our planned PV and battery system.
The planned SolarEdge installation consists of:
SolarEdge NX20K hybrid inverter
SolarEdge Nexis Battery Stack 20
19.6 kWh gross / 18.6 kWh usable capacity
14 kW battery power
SolarEdge Modbus meter connected via RS485
Three 100 A current transformers
I have already installed OpenEMS Edge and UI and successfully tested the simulator, RRD4J and Open-Meteo weather integration.
I also found the SolarEdge ESS component with the control modes INTERNAL, SMART and REMOTE. Our goal would be more than monitoring. Ideally, OpenEMS should optimise charging and discharging based on PV forecasts, electricity tariffs and flexible consumers connected through Home Assistant.
Since the NX20K and Nexis Battery appear to be relatively new products, I am unsure whether they are already compatible with the current SolarEdge implementation in OpenEMS.
Has anyone already gained experience with this inverter or the Nexis platform?
I would be particularly interested to know whether:
inverter, battery and meter values can be read locally via Modbus TCP
battery charging and discharging can be controlled using REMOTE mode
the grid export limit can be set by OpenEMS
SolarEdge ONE and OpenEMS can be used together
any specific firmware version or SolarEdge configuration is required
I would also be grateful for experience with similar recent SolarEdge hybrid systems, even if nobody has tested this exact combination yet.
Thank you very much for your help and for sharing your experience.
I have not tested the NX20K / Nexis combination myself yet, but as long as SolarEdge continues to support the same battery control protocol/registers on the NX series as on the previous generations, the existing SolarEdge ESS implementation should work.
The storage control protocol has been used since the first generation of SolarEdge storage systems, e.g. the single-phase inverters with SESTI interface and HV battery, and is also used by the newer generation of three-phase hybrid inverters with 48 V batteries. So unless SolarEdge changed this for the NX platform, I would expect the ESS functionality, including REMOTE control, to be compatible.
Regarding the SolarEdge meter: in my own installation I currently do not read the SolarEdge meter with OpenEMS. However, there is already a Meter SolarEdge implementation in OpenEMS, so this should generally be possible as well.
One important point regarding SolarEdge ONE: I would not recommend having two different energy management systems actively control the battery at the same time, e.g. OpenEMS and SolarEdge ONE. Otherwise both controllers could work against each other.
Additionally, SolarEdge Modbus TCP has historically supported only one simultaneous connection/session. So this also needs to be considered if SolarEdge ONE itself uses the same Modbus TCP interface.
The grid export limit can be set by writing the channel
ACTIVE_EXPORT_POWER_LIMIT
This sets the inverter’s export site limit and is intended for Power Manager installations with a connected smart meter.
One additional consideration is that OpenEMS is currently not fully optimized for DC-coupled storage systems. In a system with only one inverter, however, I would not expect this to make a relevant practical difference. This becomes more important when coordinating multiple ESS, because PV generation is DC-coupled to the individual ESS and should be taken into account when distributing charge/discharge power.
@stefan.feilmeier Since this topic is somewhat related: could you perhaps also have another look at my PreferDcPowerOptimizer implementation when you get a chance?
It addresses exactly this improved coordination of DC-coupled PV in multi-ESS systems.