Open source Smart Battery Management System https://hackaday.io/project/181453-green-bms
Smart BMS is an Open Source Battery Management System for Lithium Cells (Lifepo4, Li-ion, NCM, etc.) Battery Pack.
The main functions of BMS are:
- To protect cells against overvoltage
- To protect cells against undervoltage
- To balance the cells
Smart BMS consists of four main components:
- Cell Module (https://hackaday.io/project/181453-green-bms/log/198376-green-bms-cell-module)
- Control Unit (https://hackaday.io/project/181453-green-bms/log/198414-green-bms-control-unit)
- Limiter (https://hackaday.io/project/181453-green-bms/log/198378-green-bms-limiter)
- Android App (https://hackaday.io/project/181453-green-bms/log/198377-green-bms-android-app)
The voltage and the temperature values of each cell are acquired by the relevant Cell Module (based on Attiny microcontroller) and sent to Control Unit (based on Arduino Mega microcontroller) through a serial I2C line.
Control Unit starts or stop charging (by output relay) through Limiter, that includes a power relay for opening or closing the charging circuit.
Control Unit can also start or stop discharging by output relay.
When during charging a cell reaches the “Balance voltage value parameter”, the Cell Module connects the balance resistors in order to perform the cell bleeding.
When just one cell of the pack is balancing, Control Unit activates the current limit function inside the Limiter (the charging current is limited to 1A).
Control Unit can be connected with a Smartphone (or a Tablet) by Bluetooth.
By “Green BMS” Android app (available on Play Store) it is possible to check the Battery Pack status (total voltage, current load, state of charge…) , to check the actual voltage and temperature values of each cell and to perform several settings.
The Green BMS Android app is available here: Green-BMS App
Step by step instructions for make Green BMS are available here: https://hackaday.io/project/181453/instructions
https://www.youtube.com/channel/UCdJnQnmzJSQNOAGbZR5iExA
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The project was created using the following Open source applications:
- KiCad : to design cell module and Interface board
- QElectroTech : to design Limiter
- LibreCad 2D : to desingn Control Unit Box
- Arduino IDE : to design the code of Cell Module(Attiny) and Control Unit(Arduino Mega)
- Mit App Inventor : to design the Android Application
Lithium and other batteries are dangerous and must be treated with care.
Lithium and other batteries are potentially hazardous and can present a serious fire hazard if damaged, defective or improperly used.
Green BMS is a "do it yourself" project, with no warranties whatsoever.
Green BMS assumes no responsibility for any errors or inaccuracies that may appear in any documentation or file or any software that may be provided.
The use of this project is done entirely at your own risk and responsibility.
The use of this project may not be compliant with local laws or regulations.
Green BMS has been certified as open source hardware by the Open Source Hardware Association, with the UID: IT000007.
Certificate link: (https://certification.oshwa.org/it000007.html)
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