Since Venus OS v3.60 I’m able to control my Enphase system with (D)ESS. I’m using DESS so when energy prices are negative it would stop the Enphase system producing solar energy. I’ve tested that it actually works by switching off DESS and by turning off grid feed-in in the ESS settings. I saw the Enphase system throttling to 0W grid meter, so that works beautifully.
The next day I saw that the PV system wasn’t producing. I checked the PV system in the remote console and saw that the ‘dynamic power limit’ was set to 0W, which it was before 11kW. After restarting the Cerbo the limit jumped back to 11kW and the Enphase PV system started producing again. Now every day this is happening and I need to restart the Cerbo to reset this PV power limit.
What could be the issue here? Is this a bug? The energy prices are positive so it should not effect the PV power limit. Another questions; why is the PV power limit set to 11kW? My Enphase PV system is able to produce more than 11kW.
Could you guys do me a favour please. When this happens again, instead of rebooting, disable the limiter function in the PV-inverter menu, and re-enable it again after 5 seconds or so.
This will give me an important data point.
The problem could be that a power limit of 1.5% is too low for Enphase to start up. Specifically, the limiter code will set all inactive inverters (those that don’t report a running state, and is making no power) to a limit of 1.5%. It is known that some Fronius inverters won’t start up under 1%. Maybe Enphase has a similar limit.
I tried to switch off again the dynamic limiter and switch it back on after 5 seconds, but the dynamic limiter stays on 0W. I did not restart the Cerbo.
It is here now midday, 12:37PM and sun is shining and energy prices are possitive, not negative, so PV system should produce and sell back to the grid.
I traced the problem to what I think is an incorrect implementation of the DER Capacity information model (model 702) by Enphase. I have yet to confirm, but it seems the WMaxRtg value (maximum power the device is capable) is not a static value, and sometimes it advertises zero as its maximum power rating.
If you reboot the GX device at such a time, or if the network connection is lost and a reconnection is made, it will think the device has a 0W maximum power, and 100% of zero is of course still zero, which is why it gets stuck there.
So short answer: Problem in the Enphase firmware. At least, it looks to be that way. I’ll have to wait until after dark (in the Northern hemisphere) to confirm.
Thanks for figuring this out. Please let me know what you find the evening.
Do you make, on behalf of Victron, a report to Enphase that their firmware has a bug (if it is their fault)? Or do we need to report it ourselves?
Also, do you know why the update interval changes when switching on dynamic limiter? With the limiter off the Enphase values are updated every second, but with the limiter on it only changes every 10 seconds or so.
OK, confirmed. At night, the Envoy publishes a maximum power rating of 0W. My guess would be that it publishes the sum of the online units, and when there is no sun, they are all sleeping.
Sunspec requires this value to be static, and not dynamic. So this is an incorrect implementation by Enphase.
I have a colleague who is in contact with them. I’ll see what can be done through that avenue first.
Hi Izak, thanks for figuring this out. Missed your request yesterday, but it seems @darryl12123 did not . Thanks!
I can confirm I have seen the 0 W limit as well.
Also, this problem did not occur in the previous Enphase firmware.
. Thanks!