Hello there again,

This week I had time to work on it again and have finally some good news. I got the balancing working now on the modules.
I verified this by temporary setting it to balance all cells at full power. With a Infrared Thermometer I could see the PCB heating up and could also feel it ...

That explains why I see nothing happening. I will run it for 1h or more and see if I see anything different. Thanks!

Still nothing happening. I also tested at 3500 but that also doesn't work.

EDIT: Could it be that I see nothing because the bleed current is low? I calculated 6 1k resistors with highest cell voltage 3.94V gives me 23.6mA of bleed current. That would mean I would run it a long time before I see any ...

So I did the changes but I don't notice any balancing active on my modules. It doesn't change in temperature or voltage. From what I can see in the log is cell 1 balancing is active on module 2 and stays on. CBRESTART is working. See log (Current sensor not connected/not used, so ignore the current ...

Latest version of code.
The new log with this code:

Entering Configuration Mode Successful!
Setting Baudrate Successful!
Starting to Set Mask!
Setting Mask Successful!
Starting to Set Filter!
Setting Filter Successful!
Starting to Set Filter!
Setting Filter Successful!
Starting to Set Mask ...

Here is my latest version of my code

Here is the debug output of the registers. The cell voltages and temperatures are correct.


Entering Configuration Mode Successful!
Setting Baudrate Successful!
Starting to Set Mask!
Setting Mask Successful!
Starting to Set Filter!
Setting Filter Successful!
Starting to Set Filter!
Setting Filter ...

Hi,


As you mention, most likely are the resistors for cell balancing bleed off and the large pads are to aid cooling of the resistors. Is there more stacks of resistors on the other side of the PCB?

No resistors on other side of pcb

Thankyou woleg for the suggestions, I will try to do these ...

Hi,

I updated the code so it works correctly with more modules in the daisy chain. I'm now testing the balancing part but I can't seem to get it working.
My question is what are these big pads on the PCB for with the 6 1k resistors in parallel? Filtering of measurements?
20260408_141837.jpg
Any ...

Hi,

I have now also temperature working on the MAX17854 modules. Also made the serial output more clearer to read and made some small improvements so it uses less dynamic memory. The code is still in testing phase as i'm testing cell balancing on the modules.

Hi,

It has been a while since I posted here. Had to pause my project a bit due to school. I'm slowly getting back on my project. Wanted to give a update. I got the communication working with the MAX17854 chip. I can read cell voltages. Now working on getting temperature measurements working. I'm ...

Hi,

After a long break due to having to do other stuff I started working again on my project. A friend of mine bought also Peugeot E-208 packs. He got the pack with the modules having MAX17823 chips. The BMS2_7_4 code from Manny works with the MAX17841B and MAX17823. So my BMS board that I made ...

So I tried modifying the code to the MAX17854 chip. But I realized that this requires more experience than I have. Also understanding the datasheet and converting this to code is also challenging for me. Could someone help me figure it out? This is what I have as of now.

I have written a universal INO which covers both slave types, and the difference is mostly registers, setup, and balancing timers but the daisy chain init is identical.

Is this code from your GitHub? https://github.com/analogdevicesinc/MAXREFDES1277
Im guessing if I use this it will not work ...

I thought I mention the chips I have on the board so there would be no confusion about what I have. It can happen to the best of us. I know it will take some work to rewrite the code. I am already thankful for you guys on the forum for helping me getting the module to work. I am happy to wait a few ...

Yes 211 is indeed impossible. Don't know where this number comes from. Loose wires? I only have some cables for the loopback and all other connectors are not plugged in. So I think the 0xD3 is just a random number that the code sends? I will have a look at connecting all the slaves. Only got 2 ...

Did test the BMS_test_OI_modified2_max17845_lb.ino but still no data and the same errorByte 4. So I think my signals are off or are not right.

RXP before transformer
RXP_before_transformer.jpg
RXP after transformer
RXP_after_transformer.jpg
RXN before transformer
RXN_before_transformer.jpg
RXN after transformer
RXN_after_transformer.jpg

With the BMS_test_OI_modified2.ino code from bexander

EDIT: Could someone scope their signals ...

Do these signals look right?

TXP before transformer TXP after transformer TXN before transformer TXN after transformer

Thankyou, I think the isolator transformers im using are causing the problem. With everything wired up between the BMS and Module, I see that the signal before the transformers isn't the same after the transformers. So I will look at other ones that I can use. I will also check other components etc ...

Still not working. It fails at daisy chain init

Also when I start the code with the module connected I get this:

Entering Configuration Mode Successful!
Setting Baudrate Successful!
Starting to Set Mask!
Setting Mask Successful!
Starting to Set Filter!
Setting Filter Successful!
Starting to Set ...

I think I provided the Serial print? The second print in my post is exactly the first 100 lines I get when I start it/press restart button. Also what is exactly SPI supply pin used for? My chips are already powered.

I use BMS_test_OI.ino for SW. See attachment

When I start it with the TX and RX cables plugged in I get this:

Entering Configuration Mode Successful!
Setting Baudrate Successful!
Starting to Set Mask!
Setting Mask Successful!
Starting to Set Filter!
Setting Filter Successful!
Starting to Set ...

When connecting on BMS TXP to RXP and TXN to RXN, I also see "transmitQueue WD timeout" in serial monitor. This is with the code already running and then connecting the pins. And keeps looping


transmitQueue WD timeout
6
errorByte cleared
transmitQueue WD timeout
6
errorByte cleared
transmitQueue ...

I found something interesting to me. When connecting the loopback I see "transmitQueue WD timeout" when I disconnect loopback "transmitQueue WD timeout" disappears. So that means I see "transmitQueue WD timeout" loopback is working?

There is no short on RX. See image 1.

Image 2: TXN to RXN on the ...