Hoymiles HMS-XXXW-2T


just got an HMS-800W-2T - WiFi integrated - and I was wondering, if anyone managed it to get it connected to HA? Its not setup yet but I read, that any DTU is not needed/supported.

Any experiences?

Don’t waste your money trying to work with a Hoymiles DTU. I have the Hoymiles DTU Pro, and it is absolute trash. It crashes all the time and goes non-responsive. It happens so often I put it on a smart plug and set up an automation that detects when it goes offline and reboots the unit. I’ve been back and forth several times with Hoymiles support and it’s a well-known issue they’ve been trying to fix for over a year. Amazing for a device that is sold at around $400.

Instead, look at OpenDTU, it’s amazing. There are some OpenDTU kits that are sold that you can put together for about ten times less than Hoymiles DTU Pro. I ordered mine from BlinkyParts.com, which is in Germany, but I’m told there are some sellers in the US as well (I don’t know your location.) This is the unit you want for your micro-inverter. I liked this particular unit because it has the display, and you can see information about your system without logging into a web page. It pushes your data to Home Assistant through MQTT.

It’s sold as a kit, some assembly is required, it takes about half an hour if you know how to solder.


Thanks, but it seems that thw HMS-XXX**W** Series are not compatible with openDTU at this time.

Well, bummer. Keep an eye on that project. It’s a fine piece of German reverse engineering.

Sure! I already read some things about openDTU and AhoyDTU. We will see.

I found GitHub - dmslabsbr/hoymiles: Hoymiles ADD-ON for Home Assistant - does anyone has experiences with that? It seems I have to use S-Miles for now to get at least some data. OR I put an EM in between.

I used it for a while. The addon works fine as long as your DTU is reporting data to the S-Miles Cloud service. The DTUs report every fifteen minutes, as long as it is working.

I only stopped using it when I found another addon that pulls data directly from the DTU using Modbus, which updated every two minutes. That is as long as the DTU isn’t locked up.

For now I went to a Shelly Plug which gets the output from the inverter. I keep the SMiles account active to view the native data but it seems better to go with the Shelly for now.

I am new to the OpenDTU topic. But this website claims that there Is an assembly kit for Hoymiles HMS inverter in order to transfer data to home assistant via mqtt: Check this out!

The W series type of hoymiles invertes have the DTU built in. No chance to get it working with open/ahoyDTU.

I wish I would have known this before buying it. At least I just got the firmware update working so the Hoymiles cloud is finally connected. This was not the case when I installed the HMS-800-2T W…

I am running this now with a simple smart plug which monitors power as well. Works fine for Home Assistant, but openDTU would have been great. The soldered and configured hardware kit is laying around here now. Need to see if I can use it for something else or if I need to sell it… What a pity…

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How did you got the fw update when the cloud does not connect?

I found a Website explaining it and I followed the 2nd route B) there using my phone hotspot to connect the DTU with the internet since I didn’t want to alter my internal DNS settings in the router (running PiHole and unbound for DNS).
To get the HMS-800 back into your router, you need to turn off 5GHz Wifi first. It took me 2-3 rounds until I got a connection. After the initial succesful connection you can turn on the 5GHz again.
After successful update I recommend to restart the HMS-800 by detaching and re-attaching the DC input from your panels. I had the DTU online, but an offline error for the Microinverter in the cloud until I did the unplug procedure. After that everything was fine.

Give me a shout if you need more help on this…

Here’s the description in German:

In English via Google Translate:

Hi, I just managed to integrate my HMS-800W-2T using this add on. It is work in progress, but exposes a lot of details already.

I am happy to announce that my home assistant custom component is ready for testing for anyone who is interested.

You can find it here:

After testing, the plan is to integrate it into home assistant core.


Could you please add a sensor that provides the sum of all “Port x Energy Total”?

At the moment I have to add both trackers to the energy dashboard to get a complete view.

Would it also be possible to receive errors from the DTU, if there are some?

Since I installed the custom component, the HMS doesn’t produces energy any longer because of “net voltage too low”. But it isn’t!

Yes since the restructuring of the underlaying library I have access to much more data. Will probably be incorporated in one of the future updates.

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Yes, this is planned for one of the upcoming version.

However, you can use the Daily Energy (renamed from Daily Yield with newest version) entity for the energy dashboard. Works without a hassle for me.

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Thank you for the new release!

I think something is calculating the total power wrong:

Should be 66.4 instead 62.9W

I am reading this value directly from the DTU and not calculating it.

My guess is that this might be due to conversion loss due to DC → AC (or some internal quirks) or the inverter consuming some of this power.

I suspect “Port 1/2 Power” is DC and “Power” is AC.

In any case, I cannot really fix this since this is the value the inverter reports.