Domoticz Community Forum - Support & Discussion

I've been running this test version vor a couple of days now and it really looks promising.
It would be nice if there could be some more testers with different types of Marstek Venus batteries.
Please take a look at the github pages and comment on the issue over there and help willem and others with debugging the last issues ...

eddieb wrote: Sunday 29 March 2026 12:23 I've been running this test version vor a couple of days now and it really looks promising.
It would be nice if there could be some more testers with different types of Marstek Venus batteries.
Please take a look at the github pages and comment on the issue over there and help willem and others with debugging the last issues ...

Thanks for this. It would be great to receive more feedback.
Just to add, currently there are two versions:
1) https://github.com/WillemD61/Marstek-Venus-plugin
This is a synchronous version that works fine with Marstek Venus A and E3 and is using the api from https://github.com/IvanKablar/marstek-v ... /tree/main
But since it was not working at all for the E2 I also made a plugin
2) https://github.com/WillemD61/Marstek-Venus-E-plugin
which uses the asyncio libraries and is based on the api from https://github.com/jaapp/ha-marstek-local-api
This second one also works for E2 although still not very reliable. It also works for Venus A and others.

More detail info is needed is why and where it exactly fails. So far, it just seems a limitation of the Marstek hardware which causes messages to be lost/corrupted.

With both version I am experiencing occasional hardware resets which might be caused by the use of the Open API.

Any advice from real networking/UDP communication experts would also be appreciated.

Thanks allot for this plugin.
Currently i'm also using it on my Domoticz.
I have two Marstek E V3 and most of the time things are working fine.
There both connected of a fixed lan cable, no wifi.

The only problem I have and I'm not sure if tis related to this plugin or Open API of the Marstek.
But it looses it's "settings" every ~12 hours, not exact sometimes longer, somtimes shorter.
I get a result in the domoticz log that the device is not responding.
I then look with the application of Marstek and see it lost it power setting (800w instead of set 2500w) and even more importantly the setting "0 on the P1 meter" has changed to manual, making the Marstek not regulate.
Also the "open api" setting is set to off

I did see a mention of somebody else that this can be due to the polling rate of the device, which was at first set to "every minute"
I have changed this to "every 5 minutes" and it has improved a bit but it's not gone.
I really don't want to use this thread about the Plugin for this problem but it seems is heavily related to communicating over the Open Api.

Thanks WillemD61 for the plugin, highly appreciated. Hartelijk dank!

Does anyone have any pointers on how to handle this "fall back" behaviour?

Hi Snakfy,

Yes we all have. It is a bug that the latest firmware still did not fix.

At the moment, the API can not be used, sadly.

I am still waiting for a solution.

"good" to know I'm not alone.
So this also confirms that if i disable the Open API interface it will not reset the "0 op de meter" setting.
Which is really important for me (obviously).

I also found information on using Modbus over TCP (here https://github.com/evcc-io/evcc/issues/25373 ).
Perhaps I'll dig into that for the time being.
Hopefully a firmware update fixes the issue with the Open api

Thanks for the quick reply!

Same here

Firmware update!
naar 148.119.113

Hopelijk wordt het beter, Ik heb open api weer ingeschakeld en report back hier hoe het gaat

Unfortunately, the battery just jumped back to

- Manual
- 800 Watt
- Open Api off

So the problem has not been resolved for me.

Incidentally, I can now recognize in the Domoticz logs when this happens (see below).
When I subsequently look in the app, it has reset the setting.

Snakfy wrote: Monday 13 April 2026 20:45 Helaas zojuist springt de batterij weer terug naar

WARNING: This is an English written forum, so please reply in English so other users also can understand what you are writing!

Hi,

Yes please, because I did not get everything you said.

I also installed this new firmware version 148.119.113 and activated the API again yesterday evening.

No crash of the battery software at the moment, finger crossed!

Unfortunately the use of local Open Api on Marstek Venus still causes full resets. Whether I use the synchronous version plugin I developed initially for the Venus A or the asynchronous version for Venus E users,does not make a difference for me. (See github repositories)

In the meantime I developed a optimisation program which uses day ahead info to maximise financial gain. This runs now each hour and sets the optimum mode for the next hour taking into account day ahead. This can use the plugin setup but can also use mqtt via hame-relay and that is what I have been using now for the past two weeks and that is working well.
https://github.com/WillemD61/battery-planning

My work on the plugins will continue later when multiple people confirm that Open API is becoming stable.

Yes, same here and it proposes me to upgrade the same firmware again, I don't know why (148.119.112 -> 148.119.113)

Trying to reset it all and we will see....

Snakfy wrote: Monday 13 April 2026 20:45 Helaas zojuist springt de batterij weer terug naar
- Manual
- 800 Watt
- Open Api off

Dus probleem is voor mij niet verholpen

OVerigens kan ik inmiddels in de Domoticz logs herkennen wanneer dit gebeurd (zie hieronder).
Als ik vervolgens in de app kijk heeft hij de setting ge-reset

Marstek Fail.png

If you configured email in domoticz, the plugin can send you an alert when the Marstek resets and closes the API. Configurable in the plugin screen whether you want this.

willemd wrote: Tuesday 14 April 2026 14:39 Unfortunately the use of local Open Api on Marstek Venus still causes full resets. Whether I use the synchronous version plugin I developed initially for the Venus A or the asynchronous version for Venus E users,does not make a difference for me. (See github repositories)

In the meantime I developed a optimisation program which uses day ahead info to maximise financial gain. This runs now each hour and sets the optimum mode for the next hour taking into account day ahead. This can use the plugin setup but can also use mqtt via hame-relay and that is what I have been using now for the past two weeks and that is working well.
https://github.com/WillemD61/battery-planning

My work on the plugins will continue later when multiple people confirm that Open API is becoming stable.

This is what I want too. But Marstek Api is not working with firmware 148. Entsoe is out of office to often. So I use Nord pool, no trouble with Nord pool and waiting Marstek to fix the unstable api

willemd wrote: Tuesday 14 April 2026 18:06

Snakfy wrote: Monday 13 April 2026 20:45 Helaas zojuist springt de batterij weer terug naar
- Manual
- 800 Watt
- Open Api off

Dus probleem is voor mij niet verholpen

OVerigens kan ik inmiddels in de Domoticz logs herkennen wanneer dit gebeurd (zie hieronder).
Als ik vervolgens in de app kijk heeft hij de setting ge-reset

Marstek Fail.png

If you configured email in domoticz, the plugin can send you an alert when the Marstek resets and closes the API. Configurable in the plugin screen whether you want this.

Thanks allot for that tip .
Sorry for speaking dutch , I corrected my original post

I have ordered some parts to connect to the Modbus over rs485 connector that is on my Marstek E V3.
Trying to make it work using this plugin, not sure if it will work for the V3

https://github.com/RneeJ/Domoticz-Marstek

I also don't know if I can controll the battery over this link, but first thing i want to get working is the readout of the battery state.
I'll post experience and progress here.
Part will be delivered in few weeks..........

Snakfy wrote: Tuesday 14 April 2026 21:02 I have ordered some parts to connect to the Modbus over rs485 connector that is on my Marstek E V3.
Trying to make it work using this plugin, not sure if it will work for the V3

https://github.com/RneeJ/Domoticz-Marstek

I also don't know if I can controll the battery over this link, but first thing i want to get working is the readout of the battery state.
I'll post experience and progress here.
Part will be delivered in few weeks..........

Might be better to create a separate thread for modbus Marstek communications since it is not linked to OpenAPI at all, which is the subject of this thread.

willemd wrote: Tuesday 14 April 2026 14:39 Unfortunately the use of local Open Api on Marstek Venus still causes full resets. Whether I use the synchronous version plugin I developed initially for the Venus A or the asynchronous version for Venus E users,does not make a difference for me. (See github repositories)

In the meantime I developed a optimisation program which uses day ahead info to maximise financial gain. This runs now each hour and sets the optimum mode for the next hour taking into account day ahead. This can use the plugin setup but can also use mqtt via hame-relay and that is what I have been using now for the past two weeks and that is working well.
https://github.com/WillemD61/battery-planning

My work on the plugins will continue later when multiple people confirm that Open API is becoming stable.

I finally installed hame-relay and hm2mqtt. As mentionned previously, I get a loooot of devices with mqtt in my domoticz now.

Here are the ones I selected to appear on my domoticz dashboard :
Here is the result on my dashboard's mobile with HomeHabit :
Sadly, there is no way I can change with domoticz the working mode. On that selector, nothing's happen.
willemd, are you able to ?

willemd wrote: Tuesday 14 April 2026 22:23

Snakfy wrote: Tuesday 14 April 2026 21:02 I have ordered some parts to connect to the Modbus over rs485 connector that is on my Marstek E V3.
Trying to make it work using this plugin, not sure if it will work for the V3

https://github.com/RneeJ/Domoticz-Marstek

I also don't know if I can controll the battery over this link, but first thing i want to get working is the readout of the battery state.
I'll post experience and progress here.
Part will be delivered in few weeks..........

Might be better to create a separate thread for modbus Marstek communications since it is not linked to OpenAPI at all, which is the subject of this thread.

Yes I will do that by then, it's not my intent to hijack this thread and still highly appreciate the effort

this morning I received new firmware for my Venus E v2