@johu I tracked it down to Q5 being defective and replaced it.
All the other components look fine, and I’ll connect the BMS back to the battery.

Do you have any recommendations to avoid stressing or burning components on startup?
Would it make sense to disable balancing before power-up, or is ...

Jacobsmess wrote: ↑Mon Sep 29, 2025 12:11 pm Ah of course, when shorted what shows on your multimeter? Im a little confused as my Q5 shows around 0.7v on both working and non-working boards...

It shows continuity - it beeps.

@Mario How did you diagnose Q5? I have some possibly unrelated issues with my boards but looking for ways to test different components to identify issues.


Johu described this earlier... Measured source vs drain pin with multimeter in diode test mode... It should show about 0.5V if it's ok ...

@johu I tracked it down to Q5 being defective and replaced it.
All the other components look fine, and I’ll connect the BMS back to the battery.

Do you have any recommendations to avoid stressing or burning components on startup?
Would it make sense to disable balancing before power-up, or is ...

errinfo=988 means it got a 988/8192 reading from the ADC despite all FETs should be turned off. So around 0.5V or so. Apparently a rather soft connection. Can you verify 0.5V on the ADC input?


Sorry, I pulled the boards out to check FETs but didn't get time to that yet. Can do it when I connect ...

Reporting status of my BMSes...

I did capacitor patch on all boards and uploaded newest firmware on August 28th. First I powered BMSes without battery and it was ok.
Then I powered up with battery connected and all worked like a charm. Balancing about 1 mV per day.

On September 2nd I decided to ...

johu wrote: ↑Tue Jul 08, 2025 10:48 am Yes you should and I very much recommend the "capacitor patch"

Argh... I wanted to skip that.

Now where do we stand?
- Mario runs 96S with v2.2, how does that go?


Not much happened since last report. I've received new board to replace #4, but didn't run balancing after installing it, I just did readouts for test. I disconnected boards and after that I was getting car ready for the ...

I finally got my car to pass inspection and got license plates. It's now registered as electric with 45kW.

The car got weighted when inspected and there is 699 kg on the front axle and 792 kg on the rear.
That is total 1491 kg.
Before conversion it was total 1640, front: 860, rear 780.
So, about ...

Proton wrote: ↑Sun Feb 23, 2025 4:50 pm I am lost here:
I click on the first link and BMS firmware binary but I ncannot click it.

I think you just need to login to github and you will get download icon next to the artifact.

I've updated all boards to the latest firmware again CI #21.
Board #4 is slowly flashing and reporting opmode error and lasterr BALANCER_FAIL.
It also reports 0V on all channels.
balancer_failed.png

Turned off balancing for now on all boards as this reading affects total reading.

I think that ...

PetersonOctavius wrote: ↑Sat Feb 22, 2025 2:36 am all the other lines are reading just fine

Why do you use different code for min and max? It's the same thing just on different bytes. So, code for min should return correct value for the max if you read from bytes 2 and 3.

CAN mapping for ISA shunt is working nicely after configured correctly.
Here is configuration for idc and power:

Ah yes, the newer firmwares have a POST (power-on self test) and apparently that fails. This is indicated by the slowly flashing LED. In "lasterr" you can see why.
On said module there is probably an issue with the i2c comms to the ADC. Of course I don't understand why it shows now. I have ...

Few more days passed, and here’s the latest status...

Good news: Delta is dropping by about 1mV per day.
subvalues205247.png

I raised cell voltage from ~3.7V to ~3.9V and ignored delta changes in between. Now I’m keeping it between 3.85V and 3.92V to make it easier to track delta differences ...

johu wrote: ↑Tue Feb 18, 2025 10:06 am Interesting, I could change the sequencing so it doesn't scan 0,1,..15 but 0,2,4....15,13,11,...1 . So less potential jumps

Sure, if you think it's worth it. Happy to test it out!

What happened to 1.09 though? Looks like it was discharged too much? Also 2.00 is flickering. Is the connection good?


Could it be somehow related to the last and first series in the pack?
I managed to get screenshot with this behaviour on cells between boxes 0-1, and 4-5.
I can't catch it on ...

What happened to 1.09 though? Looks like it was discharged too much?

It's actually 1.08, and it has been the lowest cell since the first measurements. I manually charged it a bit earlier, but apparently not enough. The "hole" in the graph above 1.08 makes the difference look bigger than it ...

Status update after 24h:
https://drive.google.com/file/d/1GGfthETUmseFeljjOBOEQ9nLlaD1npYz/view?usp=sharing

And here’s the chart for the last 2 days, after charging to cca 3860mV:
batt2day.png

I wanted to pull out balance states durations for each cell. Since I have detailed logs from BMS for ...

Great visualization! Will be interesting to see how long it takes to even out the rest. I take it one box is 1mV?


Thanks. I'm still learning, but you can do amazing visualization with Grafana charts and loads of data for them.
It's not one box for 1mV, it really depends on the delta and with ...

Finally, I got all boards working… actually, they’ve been running fine for a few days now.

The issue with the last two channels on board #4 turned out to be bad solder joints on some of the replaced resistors. A second pair of hands and eyes caught it, and once fixed, everything started working. :D ...

johu wrote: ↑Wed Jan 29, 2025 10:10 am Ok, could it be it's because you measure in circuit? Is the 5V rail at the correct level? If so, don't change them.

I don't know if it's because measuring in circuit... I just know how to put probes on the pins and read value.
Thanks, I will check 5V rail level...

johu wrote: ↑Wed Jan 29, 2025 6:35 am Yes, the BOM on Patreon is a bit outdated, will update. The values should be R9=100, R12=10k, R16=51k

Thanks, that makes R9 ok as it measures 100R, but other two not. I measured R12=8k5 and R16=12k2

I wanted to follow up on my last message...
I ordered and received the components and have now replaced all the resistors I previously identified as bad. The latest voltage readouts from all boards are available in the "0128_1800" sheet in this document:
https://docs.google.com/spreadsheets/d ...

I've received the P- and N-channel MOSFETs and replaced all six components from my previous messages.

After the first attempt, I got these readings:
u0 1.15625
u1 0
u2 3894.46875
u3 3895.03125
u4 3894.46875
u5 3866.25
u6 3903.25
u7 3886.21875
u8 3902.6875
u9 3835.71875
u10 -177.34375
u11 403.46875 ...