Supprt JK-B2A20S20P

[markusgg84]

I've got the JK-B2A20S20P BMS, I tried to comuicate with RS485 and Bluetooth.
RS485 didn't work but bluetooth did. But some values are missing. I think it is because JK-B2A20S20P ist not supported yet.

The log lists some unknown values:

[13:11:14][D][jk_bms_ble:469]: Unknown112: 00 00

[13:11:14][D][jk_bms_ble:559]: Unknown158: 00 00 (always 0x64 0x00?)
[13:11:14][D][jk_bms_ble:562]: Unknown160: 00 00 (always 0xC5 0x09?)
[13:11:14][D][jk_bms_ble:575]: Unknown168: 00.00.00.00.00.00.00.00.00.00.00.00.00.00.07.00.00.01.00.00.D4.03.00.00.00.00.FB.48.40.40.00.00.00.00.E2.04.00.00.00.00.00.01.00.05.00.00 (46)
[13:11:14][D][jk_bms_ble:589]: Unknown189: 03 00
[13:11:14][D][jk_bms_ble:593]: Unknown192: 00
[13:11:14][D][jk_bms_ble:595]: Unknown193: 00 FB (0x00 0x8D)
[13:11:14][D][jk_bms_ble:597]: Unknown195: 48 40 (0x21 0x40)

Is there a way to support JK-B2A20S20P?

Thanks!

Regards,
Markus

[syssi]

This missing values / the unknown values are always unknown independend of the BMS version / model. Do you miss something?

[syssi]

I would like to mention your BMS model as supported. Could you provide a screenshot of the device info view of your android app or the "device info" response printed to the Esphome log on startup? Thanks in advance!

[markusgg84]

[markusgg84]

It worked but now i get an error while writing the image to the esp32.

INFO Uploading .esphome/build/jk-bms/.pioenvs/jk-bms/firmware.bin (1380288 bytes)
Uploading: [======================================================= ] 91%
ERROR Error sending data: [Errno 104] Connection reset by peer

Any recomendations?

[syssi]

The view I'm looking for is called "about" page:

[syssi]

The BLE connection is very resource hungry plus the coexisting of WiFi and BLE is challenging for a ESP32. You could add a safe mode reboot button to the configuration if OTAs are trouble some.

[markusgg84]

[syssi]

Did you solve all your issues?

[markusgg84]

Yes, thank you very much!

[xFallon]

Hello, I am very interested in this model:
JK-B2A20S20P,
HW: V10.XW,
SW: V10.10
and RS485 communication. BT works fine.
So I try the v4 protocol from 9600bds it doesn't work for me and neither do the other JKS02/04 115200bds protocols.
Does RS485 communication work for this model now? How?

[syssi]

This external component should work for your model but there are some devices out there which doesn't respond to UART traffic. Where did you buy the BMS?

[xFallon]

From AliExpress
https://www.aliexpress.com/item/1005003719416234.html?spm=a2g0o.order_detail.order_detail_item.2.28b8f19czhULDW

[syssi]

The devices from Hankzor should work in general. What did you try exactly?

[xFallon]

First I tested BT esp32-ble-example.yaml and it works perfectly,
then esp32-example.yaml.
I just changed the board to esp32doit-devkit-v1 but there is no communication on Rx.
So I researched further and found github://syssi/esphome-jk-bms@add-protocol-v4-support and tried it, there was communication on Rx but it looked like Echo Tx.
I will try another board and a shorter cable (now 1m) between BMS and ESP at the weekend.

[syssi]

This is the correct configuration example for your BMS model: https://github.com/syssi/esphome-jk-bms/blob/main/esp32-example.yaml

Please make sure to connect the ESP directly to the UART-TTL port of the BMS. Please avoid the RS484 dongle.

[xFallon]

Hi, after some testing I found that the problem between JK-BMS and ESP32 was a 1m long shielded cable. I didn't think that the 3V3 TTL interface was so sensitive. I used a cable about 10cm long and everything works perfectly.
And now I will try to connect CAN-BUS (https://github.com/Uksa007/esphome-jk-bms-can)
Thank you very much for the idea and your good work.:)