Zero export and Max power not working as expected.

[ddaddy]

I’m away from home for a few days so thought I’d try out the zero export and Maxpwr features.

I have 6x QT2 inverters, 21 panels and an ECU-C.
Currently generating and exporting over 3.5kw at the time of testing.

Zero Export

I flipped the Zero export switch then left it for half an hour. When I checked again, all panels were producing zero and the house was importing 200w.

I’m trying to understand how it should work. Perhaps the 200w house usage is too low for the 6 inverters to manage?

Max power

One Inverter I set to 200w and enabled the On/Off switch, as i wasn’t sure if this switch was related to Maxpwr. The 3 panels on this inverter continue to produce 340+ each. Later I disabled the switch and after 30 minutes it’s producing nothing! I re-enabled and soon it started producing again but ignoring the 200w I set 🤷🏼‍♂️

Another inverter I set to 200w and left the switch off. This one eventually ramped down to ~200w per panel.

A third, I accidentally moved the Maxpwr slider from zero, but now it can only go down to 20 at the lowest (there’s no 0 on the slider). With the switch off, it continues to work at full generation.

Am I misunderstanding how these features should work?

What I think is happening.
If a Maxpwr figure is set, the switch must be on. If off, then zero production occurs.

Maxpwr is initially zero, but if you touch the slider you are now invested as there is no way to set it back to zero and thus must enable the switch and set it to 500 for normal production.

There may also be some disconnect between initial values after installation if these features have never been used?

[HAEdwin]

Hi ddaddy,

Thanks for you feedback.

Zero Export: Since I don't have an ECU-C myself, I can't test it any further. So I assume the standard parameter that can be set would do it's job. I do know that this setting is strongly dependent on the CT terminals. After all, the ECU-C needs to know what the electricity demand is in the house in order to be able to adjust. I don't expect it to respond very quickly to changes. A home battery would probably be able to manage it better. But the best point of measurement is the utility meter because of the interval (5 min. at the ECU endpoint).
In general, be patient with the ECU. Don't draw conclusions from a snapshot but judge over time by analyzing the graphs. It should improve Zero Export somewhat but I expect it will not be able to keep it right at zero.

Max power: So it looks like flipping the switch doesn't take into account the previously set Max Power. That's a firmware issue, unfortunately I can't do anything about that. Use an automation to correct that.
20 is indeed a firmware limit, even if you would try to set it lower the ECU will respond with: "Please enter an integer between 20-500 !" and does not accept the setting so that's why it is limited in the integration also. Screendump of the UI in the ECU-R-pro and ECU-C:

Unfortunately, we are largely dealing with the limitations of the firmware and should not expect the PV installation to respond by the second. The entities are primarily intended for use within automations and therefore I have left all interdependencies as generic as possible. I would recommend using automations, this way you can for example precede setting Max Power by turning on the inverter to make sure it works. this way you will also use the excellent features of Home Assistant. Keep pauses between the commands you send to the ECU, please be patient as the response is not that fast!

As for the last sentence you are right, it is better to assume that it is not at zero but at maximum. I will adjust that in the next version.

[ddaddy]

I did wait 30 minutes between changes to see the effects.

Re. Zero export, you can see here that at 9:45 when I switched it on, there was zero generation until I disabled it 1:30 hours later.

I must confess, I’ve never managed to get zero export working, as the web UI is very confusing. Even the on/off switch has confusing language. I just assumed you’d maybe figured out how it properly works so tested your switch.

Re. Max power, I’ll have to wait until I get home, but I wonder what the default settings are if you’ve never used this feature.
Perhaps it should always be 500, but home assistant has it at zero (I assume this is coming from the router too?)

[HAEdwin]

From what I understand from the graph, zero export works.

1. You don't export energy anymore and
2. Everything you generate is consumed so you don't see any production. I would consider production as something that is surplus, something that is left over (unless you started the heavy energy consumption at 11:15 and not earlier).

For Max power I've seen initial values like 364W and reading the parameters takes 5 minutes before getting results but I don't see them so that's an issue. Have to figure out a way to do a good representation of the actual value.

[ddaddy]

The period of zero export, also had zero generation but 200w house usage (import).
After I disabled zero export and the panels started generating again, my automation kicked in and turned my pool heater on, which is why usage increased in line with generation.

I will try again using zero export and enable the pool heater (3kW usage) to see if it generates, but I suspect it will generate zero again.

[ddaddy]

Damn, that was an expensive test, as I completely forgot about it.

Zero export enabled with 3kw+ usage. Generation dropped to zero and remained there 😫

[HAEdwin]

I can't say anything about it, maybe some other users can be found in the discussions who have the same experience (or not) and do own an ECU-C using zero export.