The Open BMS Project is an open source and open hardware project with the goal of developing a reliable, rugged, high quality BMS (Battery Management System) for lithium-ion batteries, available for everyone. While there are many commercial suppliers of BMS, few are suitable for home builders, amateurs, student teams, prototyping, and other small-scale users with limited resources. The commercial products are typically expensive, and the design and software is typically proprietary. They are “black boxes” that cannot be modified or improved by the user.
The Open BMS Project is based on three fundamental principles that the BMS must adhere to:
- Do no harm!
- Draw equal from each cell in stand-by, and as little as possible.
- Fail in a benign, predictable manner.
These three principles may sound like nothing but common sense, but there are unfortunately many commercial products that don’t adhere to one or more of these principles.
In addition, the idea is to create a system based on “functional layers”. This will allow the user to pick only the functions he or she needs for the particular application, decreasing cost and complexity. Layers can also be removed in order to troubleshoot the system. Examples of functional layers would be cell balancing, cell reporting, high/low voltage alarm, temperature reporting, charger control, drivetrain control, charge level reporting, and visual interface, to mention a few.
Upgrading, re-use, re-purposing, recycling
Whenever possible, the design should consider the ability to upgrade the system to extend its technical life, re-using it on a new battery pack, re-purposing at the end of the technical life, and recyling at the end of its useful life. The aim is to minimize the use of natural resources and minimize the generation of e-waste (you can read more about e-waste and planned obsolescence here).
Don’t invent the wheel again!
The intent of the Open BMS Project is not to invent the wheel again, but to draw from the huge amount of knowledge already available in the electric vehicle community. There dozens of good designs collecting dusts on people’s shelves, and with coordination and more than a bit of manpower, we believe we can develop a BMS that will benefit the entire EV community. To save both money and work, it is also suggested that existing open source systems such as Arduino and/or Raspberry Pi should be used where suitable.
Who is behind this?
The initiators of the Open BMS Project is the wife-husband team Eva Hakansson and Bill Dube. Their interest in an open source BMS is quite selfish: they need a reliable BMS for their next streamliner motorcycle, the Green Envy. At the same time, they realize that a reliable, open source BMS would benefit the entire EV community.
Join the movement
Contact Eva on contact-eva [insert “at” here] openbms [dot] net to express your interest. A website and wiki-page will be built when there are enough interest for the project.