Hi , nice building
Now i know this board fit to GEN1 cell :slight_smile:

But with such cell in // the balancing working nice? not to low?
how many cells can we stack? I see 25 on your’s, how much can the lower one withstand?

the components are the same between v4.21 and leaf 4.00?

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ISSUE after flashing existing and new cell modules and controller with newest firmware… the Contoller cant communicate with any of the cell modules.

  • When flashing the modules and controller it uploads and reads/verifies just fine.(using PlatformIO(which i prefer) - AVRDUDE keeps giving errors)

  • But i noticed that new modules and modules that were previously flashed, the leds act(flash) differently. After flashing the new modules the red led blinks quickly and the green led blinks every 2sec on the modules. But When flashing Existing modules which were previously running older firmware it writes and reads/verifies just fine with no errors but the green led flashes quickly and the red led is flashing super fast and almost appears to be steady because its flashing so fast…

Regardless, neither modules will communicate with the controller… Ive tried reuploading bootloader and eeprom and both write and read/verifies fine but still same issue.


Ok, you can always go back to the older version, however try the set fuses option before programming.

It sounds like the clock speed is running strange.

Are you using the code from the master branch?

What I have done yesterday (one option for each try)

-B16 option on/off

-disconnect USBASP from USB Port and connect after pressing upload right before flashing starts.

  • first flash old fw then new one

  • combine

there is a bom with the gerber files its a hybrid of 4.21 and v4

i couldnt see a reason in why you woud want to stack more than 26 high, they get very top heavy and unstable if you was to go any higher

Thanks , I just want to know the stack limit if it is documented, even 25 seem to be heavy for the first module.


yea i belive it is from the master branch. at the bottom of github page in the readme section under “how to use code” i click on releases link then download the source for version Release-2021-01-25-14-42

ive tried the reset fuse option in platformIO but not sure if i tried reflashing afterwards.

ill give that a shot and report back


When flashing the latest firmware, do we still need to flash the system image “diybms_controller_filesystemimage_espressif8266_esp8266_d1mini.bin” ? when i tried to flash it it gave an error.

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No, not with the latest version for ESP8266.

Hi @Jon_Coop, if you follow the instructions to program from here [diyBMSv4Code/ at master · stuartpittaway/diyBMSv4Code · GitHub] you don’t use Platformio at all.

Just download the “” file and follow the above instructions.

I have place an order to jlpcb for leaf module
I have see it is AZ432ANTR for D1 (nice :slight_smile: )

I have a doubt about what revision need to flash v4.00 or v4.21?

Thanks for this information

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If its using the 432 chip, then v4.21 will be the one to use, if its using the LM4040 chip, v4.00.

Thanks Stuart :+1:

Hi Stuart
Thanks a lot
it is the 432 from last bom download 1 week ago on github

I think you have update the schematic but not the revision, so it is confused for me, maybe add v421 on this last leaf pcb can help to avoid mistake in firmware selection?

have a nice day

Please can you confirm this point on shematic difference between leaf and v421?
Why there is a C2 capacitor on leaf pcb and not on v421 pcb?
They use 432 on both schematic.
I think C2 is required only for LM4040 for better stability, but is it ok to have it with 432 on leaf pcb ?

Hi @stuart,

I saw the latest update video on yt and I was wondering if the controller board can handle 55 cell module in series or not? Currently I have 55 cell modul from V3 board and I want to upgrade my system.