To give you an idea of how slow some Maxim based packs balance, it took 6 months to resolve a 250mV delta on one of my packs.

You have three options.

1. Watch the die temps, they should heat up when shunts are active.
2. Disable AUTOBALSWDIS in the scan code, you can then watch the individual ...

Ohh, if you’re looking for change…forget about it. These balance really slowly. Check the thermals (die temp) for indications of balancing.

All your cells are below the startShuntVoltage.

Line 83 change to

Register 0x70 (BALEXP1) is zero, that means there's no balance timer set.

Value 0x3FF operates balancing indefinitely (no timer expiration).
Default value 0x000 disables cell balancing (preconfigured timer expiration). (pg. 267 Max17854.pdf)

Change line 1729

writeAllSlaves(0x70, 0x0258, true ...

Can you attach the latest version of your INO code please?

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 ...

Keep it up. I’m interested to see your progress on this.

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.


You should not need to ...

Yes 211 is indeed impossible. Don't know where this number comes from.


0xD3 is a fill byte as described in the following data sheets - so there may be an off by one issue here.

https://www.analog.com/media/en/technic ... X17843.pdf
https://www.analog.com/media/en/technic ... X17854.pdf
https ...

After a quick look in the MAX17854 datasheet, it should be possible to port the code to work with this chip but it will take some work. Alot of the registers have different addresses, as @woleg says several times.


Your code should work fine up to the point of HELLOALL as addressing is common ...

Try this modified code.
BMS_test_OI_modified2.ino

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.


Hi zuuus,

I assume you are running the ...

If these modules use Max1785x slaves and you are struggling for support let me know. I have an STM32 and ESP32 solution.

Here's what the preamble should look like on both MAX17841 TX -> MAX17845 RX (up) and MAX17845 TX -> MAX17841 RX (down) pairs.

Hi,
Im currently working on my project with A Peugeot E-208 battery pack. The modules use MAX17854 chips and I use the PCB design from Manny with Arduino pro mini, MAX17841B along with BMS2_7_4.ino code, but I running into a problem where the serial monitor says:
errorByte cleared writeAll ...

YankeeB wrote: ↑Thu Oct 30, 2025 2:03 pm Hi, does this work with the KIA EV6 BMS?

For the Maxim ISO BUS connection, yes. These are the 2x twisted pair which forms a daily chain between the modules.

AmeldePamel wrote: ↑Fri May 09, 2025 11:23 am Hello, can this board also communicate with the BMS of a Kia Niro?

Yes. I have a few complete Maxim ISO-SPI dual CAN boards now rather than just the SPI interface. They use an ESP32-C6 and Arduino.

77evzen77 wrote: ↑Tue Mar 04, 2025 4:13 pm Hi, I would like to ask where it would be possible to get the module that is in the 6QupRET.jpeg with MAX17841??? many Thank Evzen

I have one left. It’s not too difficult to reuse the hardware from the vehicle if you have the main control module.

If anyone is having no comms issues with these modules there may be a fundamentally different slave IC in their packs.

Tried all the code shared here only to find the modules I have are MAX17854 as confirmed from reading register 0x0.

Currently working my way through new code based on the ...

If its supposed to be CCS EV to ChaDeMo EVSE it would be more complicated.


Yes, this is the plan. I suppose it would be easier to start with an open ended implementation of CCS and then patch in the mocked CHAdeMO vehicle as middleware.


Are you aware that the Ph.2 has (different to Ph.1) a ...

I’m not 100% sure but from a quick search that Mercedes uses CATL packs. The only interface I know that works with this tech is the MAX178xx controller.

This thread should put you in the right direction. https://openinverter.org/forum/viewtopic.php?t=2181&start=25

I do have some spare SPI ...

Hi,

Thought I'd share my £12 off the shelf setup, no soldering required!

I wrote a Solax battery emulator almost 2 years ago now and have been using that code to use unmodified Renault EV batteries on Solax and FoxESS kit. Over the years this was adapted for 65V Victron kit (BYD emulation) and so ...

Modbus control is done on pins 3 & 4 (Modbus Meter is 1 & 2)

There's a discussion here for driving the inverter manually. https://github.com/nathanmarlor/foxess_ ... ssions/513

There’s no need to simulate a power meter, you can drive a FoxESS manually by commanding power.

I’ll edit this comment with a link to their internal communications specification document.

Here: https://drive.google.com/file/d/1eZSxXRflruOIlPNNiN7fuOvuC0YZZzjg/view

Look up Active Power ...

Hey there, I may able to help you out with your Zoe PH1 CAN data. Let me setup a repo and I will add some DBC files and an extensive collection of logs (which I think were found in here).

Edit: Logs can be found in this forum here https://openinverter.org/forum/viewtopic.php?p=40132#p40132 and I ...

For the V2X application, I already need to accurately report battery current to the ChaDeMo CAN interface. By offsetting this and reporting to the inverter via RS485, I can control the charge / discharge current.


I have a copy of the official CHAdeMO spec and built my own library based on it ...