I just found I get a lot more info on the PC browser than my phone. What can you tell from this? #2 I have installed a new CPU and a different optoisolator, same kind just from another board. These oos and crc mainly happen when the board is in bypass. And when I say #2 I mean physical #2 so #1 in the Pic, it wasnt passing the packets from #1 to #2 but after the new CPU it seems to pass them along but still losing packets. I am using these boards created by Allan Lind who tells me his are working flawlessly.

So I just replaced CPU’s #0,1,6,10,11

No more crc errors, now only OOS.

Also I’m using the 9k6 comms speed.

The “bad packet count” means that individual cell received a packet of data which was corrupt - so the corruption occurred between the previous module and that one.

Usually, running at a slower clock speed will help, as it allows the ATTINY to align to the data stream more accurately.

Nevermind, i found some more parts i think got damaged too, so i think i will order parts for building a new board

What can Out Of Sequence errors indicate?

Out of Sequence is basically the same as a CRC error except that instead of a corrupt packet you have no packet. Possibly a missed wake-up interrupt or something like that.

I’ve been replacing cpus to fix the crc issues, oos must also be hardware related since the creator of the boards runs 9k6 comms speed and has 0 errors. Could optoisolators be a culprit? I can’t imagine that I got 114 bad CPU’s. I’m starting to run out of ideas beyond ordering new boards and cpus and spending another $400.

@Tim_Yorba a lab environment is very different to what people have built themselves.

Drop to a slower baud rate - 5K is plenty.

Does anybody have an extra current monitor board they would be willing to part with? I can’t see making an order on Jlcpcb just for 1 board. Preferably in the US.

Hello Nico
Do you still have a few pcb please?
Thank you

Hi Robert
Yes the full quantity is available

My mistakes, your modules are for leaf. I am looking for standard ones… Please excuse me.

Hello everyone,
I am new here, have already checked the majority of the videos (very impressive, thank you!) and have following question: is the balancing done purely by resistive energy burning and is it centrally controlled?

Is this balancing principle more beneficial (the preis is lower e.g. compared with inductive solutions like DC2100 which is for me “unpayable”)?

If somebody could share his experience regarding the effectiveness of the circuit that would be great.


  1. Yes. Thats the function.
  2. Dont know if its more beneficial.

But its an easy solution. Active balancing needs complicate cableling.
This system is very flexible and can handle a huge amount of cells.
It has a webserver and can be installed in your home WIFI to monitor and configure.
It has diffrend relais to switch functions.
It has RS485 and also a CAN BUS solution.

And its easy and cheap to manufacture and configure.

I have a strange issue with my newly built BMS
4 prismatic 304Ahr cells in series
When the controller sends a packet it seems to do multiple ‘round-trips’
the controller flashes, then 1,2,3,4,1,2,3,4,1,2,3,4 etc no extras controller flashes

The controller also reports each received packet via mqtt i.e. they arrive in bursts

BUT the rx & tx packet counters increment together so it would seem the controller is sending multiple packets

Communication speed is std, 6000ms interval latest controller & V4.4 cell boards

thats how it works it sends multiple packets incase one gets missed

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hi stuart did the 2D/3D mode get removed from the esp32 version?, i cant no longer see it on the september build on the main screen, used to be at the bottom of the screen

I’m running the 2022-09-06T10:32:56.505Z version and it’s on there for me (although I could have sworn it wasn’t at first!!)

(& thanks for clarification re the packets)

weird i just went back into it and now it shows it ?!?!?

The controller flashes “green” when the “enqueue_task” is called. That function can request multiple packets of data to be sent, and this is all normal behaviour.

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