New open source smart BMS

[Green-bms]

Hello, I would like to share my project with you, in the hope that it will be of interest to you.
I made a BMS for prismatic cells, with modules that are fixed to the positive pole of each cell. On my first project I used Winston Lifepo4 cells.
Each module is based on Attiny microcontroller and communicates in I2c with the control unit based on Arduino Mega.
The BMS is controlled and managed via an Android application on a smartphone connected to the BMS via Bluetooth.

I decided to share Open Source the whole project on this site:
Green BMS – Smart BMS Bluetooth Open source

I also created the Youtube channel:
https://www.youtube.com/channel/UCdJ...SQNOAGbZR5iExA

Here you can download the Android App that contains the offline demo, in order to see the features it offers:
Google play Green BMS

[mbartosch]

Where‘s the code?

[goboatingnow]

“The download of all the project files will be available until the end of september 2021”

Message on the website

[mbartosch]

There’s no link at all in the original post.

[Green-bms]

Originally Posted by mbartosch

There’s no link at all in the original post.

The link has been removed.
You can visit the site from link on my Youtube channel or searching "green bms" on Google.

[seandepagnier]

Originally Posted by Green-bms

Hello, I would like to share my project with you,

What does it cost? My chinese BMS works and cost $11

Also, are those resistors?? Why not use active balancing?

[seandepagnier]

Do you really use IRFZ44N ?? This is an obsolete part and wastes much power.

[mbartosch]

No github repo (yet) and seemingly no SignalK support. The control unit seems to dissipate 5.5 W. I'll delay spending time watching the videos until I see some specs, code and schematics...

To the OP, no offense intended, I am genuinely interested in your project, I just am an old OpenSource fart who is not keen on watching a YT clip instead of reading some hard facts or code.

[Green-bms]

Originally Posted by seandepagnier

What does it cost? My chinese BMS works and cost $11

Also, are those resistors?? Why not use active balancing?

It's an opensource design, nobody sales it... I'd like to share the project.
Assembling myself, each module costs 6 euros.
I'm interested to your chinese BMS, please send me the link...is it smart?

It was difficult for me to design active bms.

[mbartosch]

BTW, I happen to have a BMS which is also ATTiny and Arduino based. As the vendor has left the market the product does no longer get support or replacement parts, so I reverse engineered the cell module hard and software (but not yet the controller module). You can find it here, including schematics and a link to the GitHub repo containing an alternative firmware I wrote for the cell modules. Maybe this is of interest for your design.

https://www.entropypool.de/2021/04/1...e-engineering/

[Green-bms]

All project files are available at the following link: https://github.com/Green-bms/SmartBMS

[Green-bms]

I made the step by step instructions to build Green BMS.
You can find them at the following link: https://hackaday.io/project/181453/instructions

[goboatingnow]

Looks good

[seandepagnier]

Originally Posted by Green-bms

It's an opensource design, nobody sales it... I'd like to share the project.
Assembling myself, each module costs 6 euros.
I'm interested to your chinese BMS, please send me the link...is it smart?

It was difficult for me to design active bms.

Do you mean 6 euros for the bms, or 6 euros per cell?

My bms cost $34 for 12 cell with bluetooth:
https://www.aliexpress.com/item/33000199655.html

I prefer free design though

[Green-bms]

Originally Posted by seandepagnier

Do you mean 6 euros for the bms, or 6 euros per cell?

My bms cost $34 for 12 cell with bluetooth:
https://www.aliexpress.com/item/33000199655.html

I spent 6 euros per cell, purchasing components from China and waiting for month...difficult for this project to spend less than 6 euros/cell...to which you have to add another 80 euros for the Control Unit...
Let me say that the forum administrators have classified me as a provider ... but I'm just a hobbyist who has decided to share their open source project!

My bms is mainly a proposal for those who want to experiment (without warranty) and have a system open to new evolutions (for example Iot).
It is not mass-produced, it cannot be priced very competitively.

But let me tell you that your Chinese passive bms has a good price, but has a big limitation: the balancing current is 60 mA...
If you have an unbalanced cell it takes many hours to bleed.
The BMS I propose allows you to choose the balancing current, up to a maximum of 1A