Try this modified code. EDIT:
Code updated again.
Added clearing more registers at start-up and during fault detection.
Changed setup to take numberOfSlaves, numberOfCellsPerSlave and numberOfTemperatureSensors into account.

I did not see that post when I wrote my answer. I started typing before you posted probably.

Anyway, good news.
In first print out you have successful initiation, meaning slave communication is up and your wiring is correct!
Now lets start finding out why writeall fails.

Please provide a Serial print out of you current setup.
The first 100 lines or so is enough to start with. Meaning directly after power on.

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

Ok, I'm a bit confused...? I think, I might have missed something here?
From the begining in your serial output you got "UARTSlaveDevicesWakeUp WD timeout" directly after "Daisy chain init" which tells me the slave communication is not working properly and all other faults are irrelevant. That's ...

System2.png
Refering to picture above. If I understand correctly your measurements are taken at 1, 2 and 4?
Signal is good at 1 and 2 but not good at 4.
What does the signal look like at 3?

Another test idea.
What if you disconnect the slave module and loop the connector i.e connecting RXLN to ...

Whats your conclusion from those measurements?
To me it seem like there is a wiring or HW problem. The signal should return (RXP/RXN) to the MAX17841 with close to equal amplitude as it was sent (TXP/TXN).

And still same result in SW?

So the output signal is about 1Vp-p and the returning signal is about 50mVp-p so not much of a signal returning.
To measure this correctly one should use a differential probe but they are expensive.

The best one can do with a single ended probe is:
Connect only a ...

When connected with cables with one module and the loopback at the end of the cables.
How does your signal on the RX-pins look?

To me it looks like your pinout for the loop-back is wrong?
From the CMC documentation: And looking at your loop-back: Seem like loop-back is connected from pin1 to pin9 and pin2 to pin7?

The BMS.pdf was my first attempt and is incorrect. A bit further down in the thread you will find BMS_5.pdf, that is what I use for all my bms:es. The difference is you use 10nF and I use 1nF to gnd on the center taps on the transformers. Also I use 1,5k where you use 470R on rx lines. Don't think ...

If understand correctly you are using the original cables but only one slave module connected, without modifications to the cabling? That will result in no rx-tx top loop. You would need to to a loop-back where the next module where do be connected. Or connect all slave modules as per original ...

Yes, it's the start of the output that is interesting in this case.

From serial output:
"Daisy chain init
UARTSlaveDevicesWakeUp WD timeout"

Searching the code this is only set at one place, during step #5 of the slave init. This is the first time the SW wait for a reply from the slaves so this ...

Ok, when you can, please post full serial output and also the code that you are runing.

I have currently one module connected which has 6 cells and im using the original wiring harness from the E-208 pack. I have also changed that in the code to my setup. Im using a ATmega328P (5v, 16MHz).


Have you changed the software to work with one module and 6 cells?


I think the MAX17854 ...

zuuus wrote: ↑Fri Nov 07, 2025 5:20 pm Could someone help me figure this out? I have no clue what it could be. Thx in advance!

Please provide more detaila about your setup, number of cells per slave, number of slaves and also the entire serial output. Then I might be able to pin point whats causing this.

Depending on what you want to do different rules apply. Please, provide more details on what you plan to do. Then maybe I can provide more relevant information about specific rules and if this would be possible to register.

Very cool!

LRBen wrote: ↑Fri Jul 11, 2025 10:13 pm The big round baler is probably too much to ask as the PTO requirements for that are around 50kW, no question it will run it, but just not for a useful amount of time.

Would be very interesting to know how long the motor could sustain that amount of power...

Catalin wrote: ↑Wed Mar 19, 2025 6:26 am I get nothing, no output or communication frame. I’ve tried different setups but nothing…I tend to belive is dead for good:(

I agree, sounds like it's broken.

41V is a bit low voltage. To my knowledge, the FP can be set to minimum 44V and below this you will get maximum power output protection. I never tested that for a long period of time. Try to use a batterypack with higher voltage, 13-14S for lion or 16S for life.
Even if the dc-bus is disconnected ...

I have a theory to what might have caused the failure.
While doing low voltage testing, using a 6S battery to power the inverter power stage via a heater element in parallel with a 30A fuse, the motor was jerky and the fuse blow because the encoder pins needed swaping. Swaped the encoder pins and ...

Was that a fluke or an actual standby current? If so that would be worrysome.


I can't really say regarding the current. Will pay more attention to it once the inverter is replaced.


An intermittent gate drive signal could be unhealthy, perhaps... I like to check the connector pins with ...

Are there any checks that can be done to the OI logic board to rule it out as the cause, just to verify the same thing doesn't happen again?
Could it even have been the cause in this case? Seem very unlikely to me.

Diode tested it before my first post. All three low (if I remember correctly) transistors show 0,0V when doing diode test. Was 0,3V before, so indeed broken. I have not checked gate drivers for red light but I think diode test is enough.

Thank you johu for checking the parameters. Now that can be ...

I'm helping a friend getting his LDU to run.
Followed Damien:s video and everything was fine spinning the motor smooth and controlled on 22V via heater element.
Reconfigure with full pack, 72S (12 Tesla model S modules). First spin on HV battery in forward works fine (very smooth and at low speed ...

The outlander rear motor is alot smaler than the leaf and would still provide more torque than stock motor/gearbox (59*2,8). Connect it directly to transfere case an retain hi/low gear. How much room for batteries would there be left then?