New open source smart 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 that I installed in my daughter's e-max scooter (16s 48v)
It is a BMS for prismatic cells, with modules that are fixed to the positive pole of each cell.
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:
https://hackaday.io/project/181453-green-bms

I also created the Youtube channel:
https://www.youtube.com/channel/UCdJnQnmzJSQNOAGbZR5iExA

Here you can download the Android App that contains the offline demo, in order to see the features it offers:
https://play.google.com/store/apps/details?id=appinventor.ai_sergio_ghirardelli75.Green_bms_0_0

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

Wow, looks like you got a ton of work into sharing this project :thumb:

Where'd you pick up circuit board design proficiency, any tips? Seeing projects like yours where you integrate PCB design as well as programming/app design, well I can't help but feel a bit outclassed haha! Anyway, nice job - hope it helps some people out.

vanturion said:

Wow, looks like you got a ton of work into sharing this project :thumb:

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About a year and a half of work

vanturion said:

Where'd you pick up circuit board design proficiency, any tips?

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Before starting the project I had never designed a pcb.
I found the youtube tutorials a very useful way because in a few videos of 5 minutes each, they teach you the basics to start building your circuit, avoiding you to spend a lot of time reading manuals...
In Italy for example there is this channel which is fantastic:
https://www.youtube.com/playlist?list=PL9_01HM23dGH9ZLkFlLV6qn2W4cEACKW7

But there will surely be something similar in English ... :thumb:

Very interesting, but I'm not too sure how well it would work on a ebike battery. The modules might take up too much room.

Do you have an estimate on what the modules and main board would cost if you build them yourself? I can see this as useful for a DIY solar battery grid backup system.

nicobie said:

Very interesting, but I'm not too sure how well it would work on a ebike battery. The modules might take up too much room.

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Yes,I agree with you, it is more suitable for applications with larger battery compartments, such as motorcycles

nicobie said:

Do you have an estimate on what the modules and main board would cost if you build them yourself? I can see this as useful for a DIY solar battery grid backup system.

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Yes, for a Lifepo4 20S / 60V battery pack (20 modules), assembling them myself and saving money on shipping (long delivery times) I spent about 6 euros per module + 80 euros for Control Unit (including Arduino Mega, bluetooth module, case), for a total of about 200 euros.

Very reasonable and less than I expected.

nicobie said:

Very reasonable and less than I expected.

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I made a more precise calculation of the costs for a 20s 60v battery pack, assembled by myself,
In total I spent around 180 euros.


Now I am waiting for an offer from an online PCB supplier to find out how much the pre-assembled boards cost.
Bye!

If you are interested, you can buy the PCBs that make up Green BMS, at the following links:
Cell module: https://www.pcbway.com/project/shareproject/Green_BMS_Cell_Module_v_0_2.html
Interface board: https://www.pcbway.com/project/shareproject/Green_BMS_Interface_board_v_0_1.html

On each page you can download the Gerber file to purchase the PCB wherever you want and you can download the BOM (bill of material) file for PCB assembling.
By the BOM you can purchase directly from PCBway the PCB assembled, but I have no idea about the costs...

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