Huawei R4850 AC support?

[MalteSchm]

Is your feature request related to a problem? Please describe.

No response

Describe the solution you'd like

Hi,

Not sure how how to best get in contact, hence the issue...

I started to integrate a Huawei AC PSU as an AC based charging source into openDTU. Not fully ready yet but I'm on a good trajectory to complete this soon. Is there interest in a PR?

BTW: I have a pending PR on openDTU that adds two battery related safety features for the inverter. It may be better suited for this project though

BTW2: I realized yesterday that my intended setup is similar to what you're using (Victron MPPT / pylontech) so I'll be using your project as a basis going forward

Describe alternatives you've considered

No response

Additional context

No response

[helgeerbe]

Hi @MalteSchm,
I moved your issue into discussion.
I'm not sure, if I have the correct understanding. Your Huawei R4850 seems to be a power supply. Convert AC to DC to charge batteries. How do you use is, or wire it? Victron MPPT is a battery chager feed by DC voltage directly from the panels.

[madmartin]

Hi,
can you describe a little more? In which way you want to extend OpenDTU-OnBattery?

[MalteSchm]

Yes it is a power supply. I will use it to charge the Battery.
My usecases are:

• I have an existing Solar System / Inverter that is located somewhere else and I can only use an AC connection to charge the Battery
• I switched to a variable price plan where I will get a different price every hour. I plan to charge when it's cheap and discharge in the peak hours

I will control this unit (and the Hoymiles Inverter) via mqtt through openDTU. This control is complex and will be handled on a different device

The Huawei is connected to the ESP32 via CAN bus. BTW: This requires a bit of thinking as the Pylontech CAN interface and the Huawei run at different speeds (which make them incompatible). I suppose we both use the CAN controller build into the ESP32 which can only handle a single bus.

Attaching two screenshots of the UI. The values would normally populate but I'm in the process of building an electric cabinet right now and don't have things connected.

[MalteSchm]

BTW: Status is that I receive current values from the PSU. They are displayed on screen. Setting limits should work but needs testing. The control / data reporting via MQTT is still something that I need to implement.
Plus the usual stuff I need to do: code cleanups, warnings, docu

[helgeerbe]

Hi @MalteSchm with the CAN interface, I can't support you. I don't own a Pylontech. This code was contributed by @berni2288 .

Our Powerlimiter has some safty features, if the Pylontech is not responding anymore. But at the end, you always should have an battery protection independent from the OpenDTU.

[MalteSchm]

I will get a Pylontech Battery so I have personal interest to figure this out :-)

There is a BMS in the Battery but I think it is better to have an extra safety net.

[berni2288]

• I switched to a variable price plan where I will get a different price every hour. I plan to charge when it's cheap and discharge in the peak hours

That sounds great. I also already thought about doing this. awattar.at in Austria also has a hourly plan and the energy price is usually very cheap around 3-4 am in the morning.

The Huawei is connected to the ESP32 via CAN bus. BTW: This requires a bit of thinking as the Pylontech CAN interface and the Huawei run at different speeds (which make them incompatible). I suppose we both use the CAN controller build into the ESP32 which can only handle a single bus.

Do you want to use both - Pylontech and your Huawei PSU - at the same time or only the Huawei? If only Huawei: that's no problem. the Pylontech interface will not be initialized when the battery CAN interface is disabled (which it should be by default).
If you want to use both, you will probably need a second CAN controller, but that's also doable: https://www.reddit.com/r/esp32/comments/yms9tp/using_2_different_can_channels_on_same_esp32_board/

[MalteSchm]

I want to use both, Pylontech and Huawei at the same time but have not finally decided on the interface to the Pylontech. The Huawei has only CAN, so there are no options. The Pylontech has also RS485 as far as I understood. This could be an alternative.

Alternatives also include:

• Use the ESP32 build in TWI (CAN) controller with two SN65HVD230 and reconfigure the controller from time to time. IMHO this is possible as the battery values will not change dramatically.
• Use a separate SPI based controller.

But nothing is decided here yet. I wanted to look at the code before deciding on the way forward.
The battery is on its way and should arrive tomorrow. But I would like to complete the work on the Huawei PSU before reading the battery. I would hope that a new battery can be charged/discharged a few times without that amount of monitoring.

[MalteSchm]

I'm almost done with the change but have run into an issue with Mqtt. It seems that the published amount of data is more then espmqtt can handle. The current implementation is almost at the edge here already. Is this a known issue?

[MalteSchm]

I think the recent re-partitioning solved the issue.

[MalteSchm]

I created a PR here: #144

[helgeerbe]

Hope, that I have tomorrow time to merge your code into dev.

[STE2k]

it would be nice to do automatic charging according to input power coming from solar >0 Watt .. same code as zero export I guess with hoymiles part of the project

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