CAN read-only the messages send by Pylontech batteries

[burleanu]

Hello All
First I want to thank you for this CAN version of the fork.
I will like to ask you if possible to make another example that just read the CAN messages send by the batteries in order to be seen by HA.
This request comes for those that have inverters that are not having communications capabilities with LiFePo batteries like me.
I did manage to get the data out from them, via canbus, but I did get stuck on the part with the alarms and warnings because I'm not that good on programing.
I was able to interpret the values that come at 0x351, 0x355, 0x356, 0x370.
But the one from 0x359 and 0x335C I don't have any clue how to make them to appear as a binary_sensor when some alarm or warnings comes.
Any help please?
Here is an example how I had made the SOC and SOH send by my battery.

• can_id: 0x355
  then:
  - lambda: |-
  uint16_t val0 = uint16_t(x[0]);
  uint16_t val1 = uint16_t(x[1]);
  uint16_t val2 = uint16_t(x[2]);
  uint16_t val3 = uint16_t(x[3]);
  uint16_t val4 = uint16_t(x[4]);
  uint16_t val5 = uint16_t(x[5]);
  uint16_t val6 = uint16_t(x[6]);
  uint16_t val7 = uint16_t(x[7]);
  float value0 = float(int((x[0])+( (x[1])<<8)));
  float value1 = float(int((x[2])+( (x[3])<<8)));
  float SOC = float(value0);
  float SOH = float(value1);
  id(battery_SOC).publish_state(SOC);
  id(battery_SOH).publish_state(SOH);

Thanks!!!

[Uksa007]

I will like to ask you if possible to make another example that just read the CAN messages send by the batteries in order to be seen by HA.

It's not something that I have the time to focus on at the moment, but it sounds like you are on the right track.
Once you have data from the can_id you can publish the updated data to home assistant using a sensor template just add the following to your yaml file:

sensor:
  - platform: template
    name: "Battery SOC"
    id: battery_SOC
  - platform: template
    name: "Battery SOH"
    id: battery_SOH

For Alarms you can use text sensors to show the text error:

text_sensor:
  - platform: template
    name: "Battery Alarm"
    id: battery_alarm

Something like this for alarms:

canbus:
  - platform: esp32_can
    tx_pin: ${can_tx_pin}
    rx_pin: ${can_rx_pin}
    can_id: 4
    bit_rate: 500kbps
    on_frame:
    - can_id: 0x359         
      then:
        - lambda: |-     
            uint16_t val0 = uint16_t(x[0]);
            uint16_t val1 = uint16_t(x[1]);
            uint16_t val2 = uint16_t(x[2]);
            uint16_t val3 = uint16_t(x[3]);
            if (val0 & 0x02) {   /// bit 1 High.Voltage.Alarm
              id(battery_alarm).publish_state("Over Voltage");
            }
            if (val0 & 0x04) {   /// bit 2 Low.Voltage.Alarm
              id(battery_alarm).publish_state("Low Voltage");
            }
etc

You can interpret the alarms from my code:
High.Voltage.Alarm val0 = 0x02; /// bit 1
Low.Voltage.Alarm val0= 0x04; /// bit 2
High.Temp.Alarm val0 = 0x08; /// bit 3
Low.Temp.Alarm val0 = 0x10; /// bit 4
Discharge.Over.Current val0 = 0x80; /// bit 7
Charge.Over.Current val1 = 0x01; /// bit 0
BMS Internal val1 = 0x08; /// bit 3
Cell Imbalance val1 = 0x10; /// bit 4

Warnings
High.Voltage.Warning val2 = 0x02; /// bit 1
Low.Voltage.Warning val2= 0x04; /// bit 2
High.Temp.Warning val2 = 0x08; /// bit 3
Low.Temp.Warning val2 = 0x10; /// bit 4
Discharge.Over.Current val2 = 0x80; /// bit 7
Charge.Over.Current val3 = 0x01; /// bit 0
BMS Internal val3 = 0x08; /// bit 3
Cell Imbalance val3 = 0x10; /// bit 4

For more info see https://esphome.io/components/sensor/template.html

[burleanu]

Thank you very much.

This is what I didn't know hot to do it.
All the other sensors were done successfully but this warnings/alarms were for me too much.
Thank you one more time for the time spent, it was worth it. I was able to make them all.
At the moment there are no messages, but I do hope I did configure them correctly and when I need them it will show up OK.

BR

[Uksa007]

At the moment there are no messages, but I do hope I did configure them correctly and when I need them it will show up OK

You should test the Alarms and Warnings to be sure they work.
You might also need to think about how the alarm/warning messages get cleared.
Something like:

if ((val0 & val1) = 0 ) id(battery_alarm).publish_state("");
if ((val2 & val3) = 0 ) id(battery_warning).publish_state("");

[burleanu]

Yes,
Thanks for pointing out!
Involuntarily I have done the clearing of the messages because I didn't like how was looking on boot because was mentioned as "Unknown" so I had to make something, so I did so:

        int alarm = int((x[0])+( (x[1])<<8));
        int warn = int((x[2])+( (x[3])<<8));
        if (alarm == 0) {   /// bit 0 No alarm
        id(battery_alarm).publish_state("No Alarms");
        }
        if (warn == 0) {   /// bit No warnings!
          id(battery_warning).publish_state("No Warnings!");
        }

And for testing is hard to create the errors/warnings but I did try with some other ID with some value inside and the alarms where generated.

Thank you again.

I think for me was the most difficult part from the time I do play with HA/EspHome because first I didn't know the protocol the batteries are talking, so I hat to try both RS485 and afterwards Canbus, then after is see is taking on Canbus I had to find/learn how this protocol works, and on Canbus is not that much info about it.
The batteries are Apleness S5285 and on the internet there is nearly nothing about them.... Even the photos are rare! I did had to open them and then I had seen that it use a BMS similar/identic with the one from Seplos. So again I had to start looking for something, now related with Seplos and there I had seen there are two variants, one with RS485 and one with Canbus.

Curiously this BMS even is respecting the Seplos protocol but doesn't reply to their software (on the other port, the one on RS485 for battery comunication).
Anyway now, with your help, I can read them via canbus with an esp32 and MCP2515 on 3.3V (with power hack for transceiver for 5V).

Something about the same difficult was to discover also what "language" my inverter talks because also that one was atypical. Is one from EaSun (SMG 2 5KP) but that don't run the software from the classic ones like MPP Solar or others on Voltronic style. Mine is having only modbus communication on RS323. So on that I had to intercept the communication between inverter and the WIFI dongle and after that I had seen that is on modbus so, long story short, now their dongle is flashed with tasmota and send rtu-over-tcp to the network, because inside the dongle was and esp07, and the sensors are created in HA via modbus integration.

BR

[kababoom]

Well done on this, awesome work !!!

Just a question, do you think it will be possible to adjust this to support a JBD BMS ?

[kababoom]

I do have a bluetooth connection working to HA with all the values, so if i read these out and send them to the inverter ...
Will see if I can get some documentation on the JBD till interface.

Thanks anyway ...

[Uksa007]

I would not recommend using Bluetooth for reading data to send it to the inverter.
Bluetooth can be unreliable, you don't want corrupt/missing data, it is best to use a serial cable connection to the BMS.

[kababoom]

Very true, thank you..

Will see if I can get information on the uart interface and look if it can be mapped.

[Uksa007]

It looks possible, I have all the info, i just need to purchase the hardware
Consider supporting me to purchase the required hardware to develop this:
https://www.patreon.com/Uksa007Codedevelopment

[Uksa007]

JBD support is in progress Alpha code at Patreon:
Consider supporting the future development https://www.patreon.com/Uksa007Codedevelopment