Two parts, one battery system
BetterBMS uses one master with one or more satellite boards. Satellites collect the cell and temperature information where it originates. The master gathers that data, determines the pack state, and controls the functions that need to happen at the pack level.
- Satellite boardsEach satellite can collect voltage data from up to 18 series cell groups and up to five cell temperatures. It also supports cell balancing.
- The masterThe master tracks state of charge and state of health, commands balancing, manages main and precharge contactors, and calculates real-time charge and discharge limits.
- Vehicle communicationThe master shares the pack information a vehicle control unit needs over the external controller area network using the SAE J1939 message set.
Why distributed sensing matters
In a centralized design, the sense wiring from every monitored cell group has to return to one point. In a high-voltage pack or a system split across enclosures, that can create a large harness and force sense wiring to travel through the vehicle.
BetterBMS satellites are placed near the modules they supervise. A low-voltage two-wire IsoSPI communication pair links the satellites and master. The result is a cleaner boundary between cell sensing inside the enclosure and pack control at the master.
What gets configured
The board count, harness arrangement, cell grouping, current limits, temperature thresholds, charge behavior, and vehicle signals all depend on the application. EVDrive uses the pack configuration to map the master, satellites, harnesses, and accessories before final pricing and fulfillment.
BetterBMS is intended to be configured as part of a specific battery system. The design discussion starts with chemistry, series and parallel layout, current limits, thermal requirements, and the vehicle interface.