Project brief
An intelligent Battery Management System for heavy-lift UAV applications managing a 12S lithium polymer pack (44.4V nominal) with cell-level monitoring to ±1mV accuracy, active balancing at 1A per cell, and a sophisticated SoC/SoH estimation engine. CAN Bus integration with ArduPilot/PX4 flight controllers provides intelligent power-based mission management including automatic return-to-home on low battery.
The supplied project emphasizes pack monitoring, state estimation, and flight-controller integration. The enrichment does not add validated endurance-prediction or estimation accuracy.
The engineering challenge
Estimate usable battery state while monitoring individual cells and supporting power-aware UAV operation.
Engineering approach
- Combine cell measurements, current integration, and open-circuit-voltage information.
- Coordinate active balancing and thermal monitoring.
- Communicate state estimates and battery warnings to the flight controller.
Features & capabilities
- 12S LiPo cell voltage monitoring: ±1mV resolution, 10ms update rate
- Active cell balancing: 1A per cell via inductor-based non-dissipative balancer
- Coulomb counting + OCV curve SoC fusion algorithm (±2% accuracy)
- SoH estimation: capacity fade tracking over cycle history
- Flight time prediction: ±30-second accuracy based on real-time power draw
- CAN Bus (ArduPilot/PX4 compatible): SoC, voltage, current, temperature
- Temperature monitoring: 4 thermistor channels, active fan control trigger
- Anti-spark connector and fuse protection for connection safety
Software & engineering tools
LTC6811 BMS IC, STM32G474, CAN Bus transceiver, Active balancing driver (LT8584), custom 6-layer PCB, Altium Designer