Multiplus 2 GX - Mqtt control in ESS Mode3 - no feedIn

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jago asked Oct 12, '21

Multiplus 2 GX - Mqtt control in ESS Mode3 - no feedIn

Hello,

I use a Multiplus2GX with Firmware 485 and 2.80 -21 to build a controllable ESS with a pylontech US2000C. The hardware is installed and the commissioning has been done with a MK3 and VEConfigure. The grid code selection for germany and installing the ESS Assistant with respect to the pylontech limits and values was quiet easy...

The communication to the MP2GX is done locally (LAN) to the internal victron broker - the keepalive message is transfered periodically and can be adjusted based on the topics I need for controlling the unit. On the WebFrontend the name is set to ESS - and the ESS (menue) page is available; here I have selected "external" control to switch to ESS-Mode3.

I use the mqtt-explorer to debug the information I send to the MP2GX and compare the behavior of the unit with the CCGX-Modbus-EXCELL sheet (the 2.70 vesion).

Everything works fine - except the FeedIn...

I can set the system to Passthru writing a "1" to the /Hub4/DisableCharge and /Hub4/DisableFeedIn topics and charging the battery works fine if /Hub4/DisableCharge is "0" and /Hub4/DisableFeedIn is "1" - the amount of power, pushed to the battery is controlled via /Hub4/L1/AcPowerSetpoint with positive values > ACOut (Loads).

Switching to FeedIn (/Hub4/DisableCharge =1 and /Hub4/DisableFeedIn =0) and changing the /Hub4/L1/AcPowerSetpoint to "0" or a negative value, always leads to "Passthru"...

I have checked all limits, tried to use the CGwacs with Mode2 - I have downgraded to the 2.73 and tried to get the FeedIn running - no chance. It seems to me, that there is a deep adjustment I do not understand which disables/blocks the FeedIn to the grid...

Perhaps someone can give me a hint ;-) Ideas are welcome.

ESS

1634029381385.png (132.8 KiB)

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Answer 1 · 2021-10-13T07:23:08Z

jago answered · Oct 13, 2021 at 07:23 AM

I have got it:

/Hub4/DisableCharge =1 and /Hub4/DisableFeedIn =0 --> does not work

/Hub4/DisableCharge =0 and /Hub4/DisableFeedIn =0 --> booth has to be "0" to activate FeedIn

Now I have to think how to deal with the information, that this parameters are on a : "Deprecated path" and if I do understand it correctly, I should use /Settings/CGwacs/... instead...?

The CCGXX***.xlsx remaks different parameters for Mode2 and Mode3:

/AC/PowerLimit - for use in ESS mode 3

/Settings/Cgwacs/AcPowerSetPoint - ESS Mode 2 - Setpoint

Regards ;-)

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Answer 2 · 2022-11-30T11:04:15Z

Joe answered · Nov 30, 2022 at 11:04 AM

Did you find out more about this? I'm in the same boat, trying so manually change these settings

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Answer 3 · 2024-06-02T10:48:27Z

I am facing a similar problem, I can not get ESS Mode3 (manual control) to work in any way - but actually this was the reason why I bought the MP-II GX, I want a battery charger and inverter that I can tell when to start or stop charging / inverting, either via MQTT or some other network interface.

With ESS in optimzed mode (either normal or battery life) it starts to work but frankly the hysteresis of the ESS algorithm is, for my taste, too slow and laggy. There is also other data I want to feed into my own algorithm. So long story short I want external control of the charger/inverter.

With ESS in mode 1 or mode 2 in general it works, albeit not as I would like it, but it starts to charge the battery when there is negative energy reported by the meter and it ramps down charging eventually inverting when the energy reported by the meter rises into the positive. This leads me to assume that in general I have the settings right.

Now in the Venus "remote console" (GUI) if I set the ESS to "Ext control" (mode 3) in order to be able to control the charge/discharge as documented via Hub4/L1/AcPowerSetpoint this does not work. The value I write to this topic gets reset immediately again by something and I do not understand by what and why - and especially I fail to see how I could prevent this. And of course setting any value even repeatedly does not show any result either.
The ESS is supposed to be passive in mode-3? But seems it's not?

Also topics like DisableFeedIn are not writable, the value gets reset after a few seconds again.

The Venus/GX is running firmware v3.32, the MP-II is running firmware 497 (AFAIK these are the latest ones).

Any help or ideas would be greatly appreciated!
(frankly this almost seems like a firmware bug...)

Cheers

nicole

Answer 4 · 2024-06-02T13:44:00Z

I think I hit a bug... mode-3 manual setting works, but only if I set the AcPowerSetpoint via dbus directly on the Venus nanopi commandline, for example like this:

dbus -y com.victronenergy.vebus.ttyS3 /Hub4/L1/AcPowerSetpoint SetValue %100

But if I do this via MQTT on the following topic:

N/serial#/vebus/275/Hub4/L1/AcPowerSetpoint

it does not work. Is this a known issue? Or am I using the wrong MQTT topic? Though in "optimized" mode (like mode-1) I see this topic being adjusted by the ESS, so I was assuming this to be the right one.

Venus firmware version is: v3.32

MP-II firmware is: 497

And still even once it works the ramp-up/-down time is very long, it takes tens of seconds to reach the target value even for comparably small values (I am experimenting in the +/- 100W range only). Is there a way to speed this up? My PV inverters are much faster than this which makes me assume that it would still be safe... I also heard that +/- 400W per second or so should still be fine, I am seeing more like 5W/s or even less ...

And as a final remark / question, it seems that AcPowerSetpoint sets a target value for the measured AC load - though I am still not sure what gets mixed into that value. Anyhow, this is not really what I would like to control. I would like to be able to control the charger/inverter, i.e. something like "start charging at xx Watt" or "start feeding / inverting at yy Watt" or "enter a neutral state" (not inverting, not charging, self consumption taken from the grid). The rest would be handled by my own software running on another computer.

Cheers

nicole

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