CT002/CT003 protocol

[rweijnen]

Hello,

If you are interested in emulating CT002/CT003 I did some discovery on Marstek Venus E and CT002/CT003, see github.

Of special interest might be discovery and query script that are in CT002 folder:
https://github.com/rweijnen/marstek-venus-e-firmware-notes/blob/main/CT002/discover-ct.py
https://github.com/rweijnen/marstek-venus-e-firmware-notes/blob/main/CT002/query-ct-meter.py

To query meter send UDP to port 12345 with the following data:
<SOH><STX>50|HMG-50|acd9XXXXXXXX|HME-3|009bXXXXXXXX|0|0<ETX>3e
where you need to provide meter device mac as shown in Marstek app (which is first 8 of network mac + last 4 of BLE mac), it expects battery MAC which I presume is used to return special data in multi battery scenario.

Meter returns something like:
<SOH><STX>103|HME-3|009bXXXXXXXX|HMG-50|acd9XXXXXXXX|-682|-632|-649|-1963|0|0|0|0|-88|35|0|0|0|0|0|0|0|0|0|0<ETX>1f

Where data is seperated by | character.

By disassembling firmware I was able to map the data like so:

{
  "meter_dev_type": "HME-3",
  "meter_mac_code": "009bXXXXXXXX",
  "hhm_dev_type": "HMG-50",
  "hhm_mac_code": "acd92XXXXXXX",
  "A_phase_power": "-682",
  "B_phase_power": "-632",
  "C_phase_power": "-649",
  "total_power": "-1963",
  "A_chrg_nb": "0",
  "B_chrg_nb": "0",
  "C_chrg_nb": "0",
  "ABC_chrg_nb": "0",
  "wifi_rssi": "-88",
  "info_idx": "35",
  "x_chrg_power": "0",
  "A_chrg_power": "0",
  "B_chrg_power": "0",
  "C_chrg_power": "0",
  "ABC_chrg_power": "0",
  "x_dchrg_power": "0",
  "A_dchrg_power": "0",
  "B_dchrg_power": "0",
  "C_dchrg_power": "0",
  "ABC_dchrg_power": "0"
}

Happy to help/assist if you'd like to take this on...

[tomquist]

This is awesome; thanks for sharing!

I did a first pass in implementing the protocol here. However, I only have a B2500 storage, and I couldn't get it to accept the readings. I will need to take another look, but I wanted to let you know in case you have some immediate idea what the issue is.

[pergolafabio]

great, gonna test this out, since i have 2 x venus batteries, but not yet an digital meter, so i can emulate an ct002 based on my smappee device in HA

just 1 quick question, by input you mean the the grid consumption, right? and output the solar delivery? so i can use these entities below in your config?

[rweijnen]

At the moment, Venus E doesn't appear to have manual CT002/CT003 addition (e.g. by IP address) so it relies on Bluetooth discovery. I did request for manual connection (to ip address) via feedback in the app.

[pergolafabio]

are you sure? there is no need to have a physicical connection (BT) between the venus and CT , cause there are lots of people where the venus is in the garden, so there is NO bt at all there, i think it does somekind of IP discovery and detect the ct003

[rweijnen]

At least from Device Management the only option seems to add via Bluetooth, once it's added it's indeed talking IP via network.

[pergolafabio]

ah ok, but if i emulate the ct002 with HA, the venus will discover them, right?

[rweijnen]

I'm not sure, from looking at the code the CT001 has a discover packet that you can send (hello) to which meter responds with hame. I think for CT002 this is in Bluetooth discovery, but I might be wrong!

[pergolafabio]

i will test soon! do you know answer on my initiial question?

[pergolafabio]

was the emu based on v118 firmware?

[tomquist]

@rweijnen I did some testing with my B2500 and it seems to attempt a connection purely through the network. However, it doesn’t seem to accept the response message my emulated CT002 generates. There might be an issue with calculating the checksums. Are you sure the checksum is included as an ASCII-encoded number rather than directly passing it as a byte (though I tried both and neither did work)?

@pergolafabio The Emulator only needs the grid consumption (input) or grid feed in (output), not the solar production. Most smart meters only provide the input which might become negative. If that’s the case for you it’s fine to not provide the output.

[pergolafabio]

ok, thnx , created a new temp sensor, that goes negative now, at this moment i'm injecting 890W to the grid (more solar then consumptiom), so thats the entity i need to use now....

[pergolafabio]

Guys, do you think you het the issue resolved?
Emulating the 002/003 would be fantastic for users with multiple batteries, it's the only meter that can handle it

[pergolafabio]

Hi @tomquist , i forked your addon and merged the PR in main to test
https://github.com/pergolafabio/b2500-meter

choose ct002 as device in the config of the addon
but upon starting, i get this below, is the PR not yet ready for the ct002?

Testing powermeter configuration...
Successfully fetched HomeAssistant powermeter value (filter 0.0.0.0/0): -1520.0W
Starting device: ct002
Traceback (most recent call last):
  File "/app/main.py", line 205, in <module>
    main()
  File "/app/main.py", line 201, in main
    future.result()
  File "/usr/lib/python3.12/concurrent/futures/_base.py", line 449, in result
    return self.__get_result()
           ^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/concurrent/futures/_base.py", line 401, in __get_result
    raise self._exception
  File "/usr/lib/python3.12/concurrent/futures/thread.py", line 59, in run
    result = self.fn(*self.args, **self.kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/main.py", line 108, in run_device
    raise ValueError(f"Unsupported device type: {device_type}")
ValueError: Unsupported device type: ct002

[pergolafabio]

ah, maybe the dockerfile needs to be changed to...

# Clone the repository and remove .git directory
RUN git clone https://github.com/tomquist/b2500-meter.git . && \
    rm -rf .git && \
    rm -rf ha_addon

[pergolafabio]

ok, that fixed it , now its running, need to check when i'm home later, my venus batteries are powered off atm :-)

Device Types: ['ct002']
Device IDs: ['device-1']
Skip Test: False
Testing powermeter configuration...
Successfully fetched HomeAssistant powermeter value (filter 0.0.0.0/0): -1247.0W
Starting device: ct002
CT002 Settings for device-1:
Device Type: HMG-50
Battery MAC: 001122334455
CT MAC: 009c17abcdef
CT Type: HME-4
Poll Interval: 1
CTEmulator UDP server is listening on port 12345...
CTEmulator TCP server is listening...