I have been trying to automatically prevent grid feed-in by my SolarEdge SE3680H inverter using Modbus commands sent by my Cerbo, but it just doesn’t work. Hope someone can point me in the right direction.
My setup:
Three-phase system with Victron MPII 5kVA inverters.
Four Pylontech US5000 batteries, 19,2kWh in total.
SolarEdge SE3680H inverter (firmware version 3.2543.0) on AC-Out L1 with LCD screen (4.320Wp PV in total).
Victron 250/60 MPPT (2.250Wp PV in total).
DESS functionality works fine. Once the batteries are fully charged, excess PV power from my SolarEdge inverter is fed into the grid. Preventing this with the Cerbo ESS dynamic power limiting function does not work. I noticed that the DESS does not consider/use negative electricity prices when charging my batteries, it only uses PV power. Maybe this is because the Cerbo doesn’t succeed in throttling my SolarEdge inverter.
I want my Cerbo to send Modbus commands to my SolarEdge, goal is to throttle or even shut down the inverter to prevent grid feed-in. According to several sources I found on the internet, this should be possible. However I also noticed that many people run into similar problems as I do. To prevent dependencies I prefer to realise this approach with standard Victron/SolarEdge functionality only, so without using Node-RED or Home Assistant.
As far as I know, the configuration settings of both my Cerbo and my SolarEdge inverter are correct (enabled dynamic power limiting, AC and DC-coupled PV feed-in excess, RS485-1 config, Modbus port 502, unit ID 126 etc).
My original SE3680H firmware (3.2537) apparently contains a bug that causes it to ignore Modbus control commands from my Cerbo. The good folks at SolarEdge kindly upgraded my firmware to 3.2543 (not publicly available), but unfortunately that didn’t help.
When downloading the configuration files using the VRM Portal (Device list => Remote VEConfigure => Download), I noticed that both my SolarEdge inverter and my MPPT do stop feeding PV energy towards my system. Based on what I have researched so far, my understanding is that the mechanism used here is different than the one I need to throttle my PV inverter.
Currently DESS will only restrict feedin if sell-prices are negative.
To verify if general AC throttling would work at all, you can disable AC and DC feedin in the ess settings when your battery is full and load is low. This then should bring the ac inverter down to consumption, if working correctly.
That’s indeed what I tried, but it doesn’t work. My Cerbo appears to completely ignore the AC and DC-coupled PV - feed in excess settings.
I am quite new to Node-RED, but I tried to monitor the Modbus traffic between my Cerbo and my SolarEdge inverter. Couldn’t see any throttling messages going to the SE, but I’m not sure if I did it correctly.
BTW: didn’t know about the negative prices, good to know. However, we had a couple of days with negative prices in April and it didn’t work then either.
Thank you. I don’t use the SE power meter, I’m not convinced that I need it since all the required information for the throttling decisions is already available in the Cerbo. Reading different stories about this, some state that you do need the meter others state that you don’t. I do have a Victron ET112 meter, but my understanding is that you can not use this meter for the PV production figures and use Modbus to send control commands. Don’t know why that is. So that’s why I get my PV production readings via Modbus TCP.
I’m aware that the Victron SE integration document states that you need the SE meter, but that seems to use an alternative method (Automatic Power Control/APC). It also refers to ‘alternative power sources’ like generators which I don’t have/need. My conclusion therefore is that this is not exactly what I need, however most sites refer to the manual. BTW: I included this information in my original post, but that was kicked off the forum because it was too long
Read the article you sent. I also did everything mentioned in Solution 4 (Matthijs’ request for help with the new release).
Yes, that was also my conclusion. It’s a bit confusing to be honest. Why would a SE power meter be needed if all the required information is already available in the Cerbo ?
