Universal BMS monitoring tool

[dumtux]

Recently, I was installing a few LiFePO4 battery packs in my house for energy storage.
To say in a short, I need a "universal" BMS monitoring tool, that I can connect to a battery pack via RS232/485 and read internal status.

Initial goal was to use it for a UPS system, as I'm experiencing 5~30mins grid power off sometimes.
Average net power consumption of my house is ~ 1.5kWh with air conditioners on.
After basic calculation, I decided to use 48V/50Ah (2kWh) battery pack.
I purchased a second-hand Narada 48NPFC50 battery from AliExpress.
I also bought a 2kW UPS inverter from AliExpress, too.
As 2kW was not enough for the peak power consumption of my home (5kW), it took some time to separate rails.
After some work done, I could manage to wire all lighting lines and air conditioner to 2kW inverter, while keeping other kitchen appliances connected directly to the grid.
It was working good at that time.

A few days later, I told about my UPS setup to a friend.
He was having a 48V/100Ah battery pack with no use, and gave it to me for free.
It was Zhongtian ZTT48100 LiFePO4 battery pack.
After bringing it to my house, I replaced Narada 50Ah battery with it, thinking to buy a bigger inverter to use for my whole home electricity.
But soon after using it, I faced to a problem: ZTT48100 battery pack is stopping to work at ~51V, after ~20Ah of discharging.
According to its datasheet, it's operation voltage range is 54V max ~ 40V min.
So, ZTT48100 has only 20Ah usable capacity, much less than my 48NPFC50.

I could reinstall my well-working 48NPFC50, but you all know - they are extremely heavy things.
It took a few hours for replacing work for me alone before.
(My gf wanted to help, but I refused her help, because I was worried if battery lifting could harm her back  )
So, I thought it would be great if I can see what's going on inside the 48100 battery pack.
I could find a bad cell, and remove/replace it, or reset BMS settings, etc., etc. ...

I googled for ZTT48100 monitoring app, but I couldn't find anything.
There was no public app (source code nor binary), no protocol documentation, with my quick search result.
After searching in depth, and posting issues on forums, one gave me the ZTT48100 BMS reading app (Windows .EXE).
I could also find the RS485 protocol documentation for ZTT48100 battery.

But I am a Linux user, I've never used or installed Windows on my computers for more than 15 years.
I didn't want to install a Windows on my laptop, or use VM, or Wine, whatever.

So, my longer question is: is there a good "universal" BMS reading software or device? If not, is it worth to make one by myself?
Regarding to the term "BMS", I'm considering BMS for energy-storaging big packs like ZTT48100, I am not considering BMS of laptop or smartphones.

[mtwieg]

The only standard interface I'm aware of for a BMS is the Smart Battery System, but SBS is based on an I2C interface, not RS232/RS485.

I understand that many BMS do use RS232/RS485 for communications, but I do not believe there is a standard protocol or command set. The connector type and pinout may also vary between vendors.

If your battery vendor doesn't provide software then you will likely have to write your own. Best bet is to discover what chip in the BMS you're talking to. If it's a common BMS chip you may be able to use software from other vendors which happen to use that same chip.

[mag_therm]

is it worth to make one by myself?

I am on linux here, and I built and wrote a datalogger and controller for a battery /solar supply for ham radio.
It uses the adc_s in PIC16F, RS232 to computer, presently Fedora 32
There are about 13 analog channels,using hall sensors for current.
For the low level tty of raw data to SQL every 7.5 second, I use bash, then python for the math side.
 Latest trial is reading next day predicted solar levels UVI with pyowm.

For me (retired) datalogger was a good hobby project, it took me at guess 3 hours per session over 2~3 months and still adding to it.
https://app.box.com/s/bd4kdp7ah9f5b590g00ofptgcps7trnl

[dumtux]

That's really great.