I have been a long-time lurker (and learner
) here on the forums, and have successfully converted my own car, a 1996 Honda Civic, which I have driven almost every day in my commute for the last 8 months and 8000 miles. It has been flawless, but it helped me to understand the BMS (or lack of) solutions that are available to the DIY community. You can see more information about my build
here. Since I design and support BMS ICs for a major semiconductor vendor, why not make my own?
I have been working on a new BMS designed to target the DIY community, and it is now time to share it with the world. Please take a
look.
The concept is to provide a safe, reliable voltage monitor with easy centralized control of balancing. Full SoC and contactor control, via integration of a system/pack controller, would come at a higher cost for those interested, and the (total system cost would be comparable to existing solutions at the same channel count). The overall approach will enable lower cost systems but cheaper for those with lower requirements (most DIY applications). The separated system/pack controller would give an opportunity for the community the opportunity to take over and provide some neat integration with Android and iOS or other platforms such as PC, Raspberry Pi or Arduino, in the vein of many other popular hacker projects. There will be a third-party system controller available for those interested in a complete solution which will interface with the BMS over CAN to provide full SoC, SoH, pack voltage and current sense and contactor control. This will provide OEM level features and capabilities. I would be leveraging my (and my partners) years of experience supporting the OEM community in their BMS and other automotive solutions. Our experience in helping them in production vehicles will be applied to this design.
The features are:
- 3-6S module structure support/cell voltage measurement [+/-1mV]
- Based on TI BQ76PL536A battery monitoring and protection IC
- Onboard 32-bit, 60MHz TI C2000 microcontroller
- 2 module temperatures per board
- Isolated stack communication (5000-VRMS)
- Interface to supervisory controller via CAN
- Simple command set
- Can be bundled in a 12S arrangement in a single sealed enclosure
- Automotive grade components and design approach
- Able to operate as standalone BMS or specialized, distributed I/O module
Additional stretch goals may be to design:
- Built-in algorithms for top-balance and/or bottom-balance
- Pack voltage and current sensing board
- Arduino code for basic operation
- Addition of active balance circuits for up to 5A always on balancing
An initial batch of boards have already been designed and are being tested now at several sites and module configurations.
Today
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