I have a confession to make.. I have been working on a diy BMS for a while now...

[Duchess]

And haven't told you guys yet.



I think its pretty neat.



I had been looking for a custom BMS or even anything that fit my particular “wants” and could not find anything interesting online I decided to just make my own from pretty much nothing. Cool huh?



And it works!!! I am still in prototype but I am soooo close to getting it completely done hardware wise and need some help with the software stuff.

Want to Play a game?

fake edit: Also- I have never done anything like this ever...

 

[Duchess]

Oh yeah it works with arduino and raspberry pi

 

[Korishan]

More details are always welcome

Looks pretty good so far. I'm assuming you are using opto-isolaters between packs to keep from shorting? If not, how are you getting around the command ground issue?

 

[Duchess]

I am going with a run of the mill front end from Texas Instruments the TI BQ76930 chip https://www.ti.com/product/BQ76930

no need to worry about any crazy isolators

 

[Korishan]

Ahh, ok. That's a good chip. I had tried a few years ago to make sense of that chip and try to make a system around it. I needed to learn more about programming, and soldering. That's a tiny chip.

MikeTheZipper has a full project thread on the chip: https://secondlifestorage.com/index.php?threads/ti-bq769x0-based-monitors-project-thread.6711

 

[FarmerJ]

I can write software code. I've been trying to learn electronics and circuit components/design and keep managing to make lots of white smoke, but I might finally comprehend Ohms Law and how to test individual components with my multi-meter.

 

[daromer]

You are writing "Current" in grafana but you are presenting Voltage

Also it looks like you dont have any external fets for balancing but only using the built in balancing. Is that correct? Because it can only max do 50mA internally.


With that said those chipsets including its larger brother 76940 are nice small ones and are embeded in many systems There are also versions on github with the popular ESP chipsets so you get wifi/bluetooth function

Good work

 

[ng.sa]

G'Day Duchess

I think its pretty neat.

[NG] I wish I had the skills to do the hardware like this, good job !!!

View attachment 25746

[NG] How have you generated this, is this using custom software ???

need some help with the software stuff.

I cannot see the interface between the SD Card ( looks like 32GB in the 3rd pic. ) on the board, are you thinking about writing output from the BMS to the SD Card ?

Are you going to build a PC app. ?

If your write your code in the language C you can blow a ROM from your code and eventually create a full hardware BMS.

 

[Duchess]

You are writing "Current" in grafana but you are presenting Voltage

Current - as in passing of time

Also it looks like you dont have any external fets for balancing but only using the built in balancing. Is that correct? Because it can only max do 50mA internally.

What I posted is not a Battery Management System. I have a different prototype for that. I have a few other versions with power fets and whatnot.

How have you generated this, is this using custom software ???

Custom Arduino code. Node red. influxDB. Grafana... ETM

I cannot see the interface between the SD Card ( looks like 32GB in the 3rd pic. ) on the board, are you thinking about writing output from the BMS to the SD Card ?

Sorry, SD card for scale. not needed for this Battery Monitoring System.

The data streaming into Grafana is real time.

right now it goes from the TI afe to an Arduino Uno via i2c to a raspberry pi running node red, influxDB and Grafana over serial. I am planning to make a plugin for node red just for the TI afe hopefully at some point eliminating additional hardware and programming.

oh btw not only do I have different versions with additional functionality there is more of a eco-system. If you notice in the Grafana snapshot it shows "Pack 1"...





it hot swaps too. I have the BMS disconnected right now on pack 2. The noisy readings on the other packs are resolved with a new hardware revision (testing on pack 1

I can write software code.

I need help with the Arduino code and hopefully something for node red.

MikeTheZipper has a full project thread on the chip: https://secondlifestorage.com/index.php?threads/ti-bq769x0-based-monitors-project-thread.6711

I saw that and I see that code all over the internet in different shapes and forms.

I cant believe nobody has asked me for what battery topology/configuration yet lol it says it on the board if you can figure it out.

peace out.

-Duchess​

 

[Korishan]

I cant believe nobody has asked me for what battery topology/configuration yet lol it says it on the board if you can figure it out

Those of us who are familiar with this chip, it kinda narrows down what it's for And yeah, i saw the screen stamps showing it's uses. I like the Bender peeking out too

 

[Wolf]

I cant believe nobody has asked me for what battery topology/configuration yet lol it says it on the board if you can figure it out.

Hm not sure but.....

Wolf

 

[Duchess]

oh yeah and

 

[italianuser]

Current - as in passing of time

Oh my, I had the same question! If it's current I'd expect to see current measurement in mAh, because 4 is volts I suppose, so how much is the mAmps? Sorry if I ask again!

 

[Wolf]

Yes if you are using Grafana pre version 8.0 and the "Old" Graph Panel instead of the "New" Time series graph that "Current" legend just means as in what is happening now. The new time series graph changes that.
Wolf