Overview
Another simple little project that snowballed into something a bit more substantial. It started as a recreation of the open source SimpBMS project, moving it away from a discontinued development board... But if we're using a Teensy 4.1 we should take advantage of the extra I/O pins, right? And while we're at it, lets add some HV Isolation to the battery comms side of things, and some better protection to the inputs... We could use the Teensy RTC and SD Card and improve the logging. And add a proper warning buzzer and eye-searingly bright red warning LED - After all NMC cells aren't renowned for their stability.
Substantially snowballed, and grew a little in size, While maintaining cross-compatibility with original SimpBMS connector choices, this should be a bit more robust and a lot more versatile than the original.
Hardware Features & Protection
The system offers extensive circuit protection, isolating power and communications on critical paths while guarding against overvoltage across digital and analogue inputs up to 24V. Key features include:
- 3x CAN Busses: All ESD protected. Includes an electronically isolated bus for battery module comms, plus switchable terminating resistors for each bus.
- Tesla Module UART: Dedicated, isolated 5V UART port specifically for Tesla Battery Module communications.
- RS-485 / Modbus: Dedicated interface (Teensy Serial8) for industrial / Victron compatible equipment.
- Robust IO Drivers: 4x Monitored 12V 5A High Side drivers, and 4x PWM-ready 5A Low Side drivers featuring over-current, short circuit, and over-temperature safety.
- On-Board Logging & Alerts: Teensy 4.1 SD card slot for RTC-timestamped logging, I2C header for OLED display, and an integrated warning buzzer.