Powertrain is the “guts” of the vehicle, responsible for distributing and managing electrical power throughout the car. It consists of three subsystems:

• Battery – Designs and packages the high-voltage lithium-ion battery pack. This includes cell selection, pack and bus bar design, battery protection system (BPS) integration, enclosure design, and mounting.

• Thermals – Develops active and passive cooling strategies for power-dense components such as the battery, motor controller, and MPPTs, ensuring reliability and performance under peak load conditions.

• Enclosures – Designs and fabricates sealed, structurally sound housings for all electronic components, with attention to IP ratings, serviceability, and integration.

Beyond subsystem responsibilities, Powertrain plays a critical system-level role, coordinating between electrical and mechanical domains. This makes it the bridge between many systems in the vehicle, and members gain experience across a wide range of mechanical and electrical concepts.

The first two sections of this documentation provide general background in electrical and mechanical design. These serve as context for the subsystem sections, which go into detail about each area of Powertrain.

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Daybreak Powertrain 2025

This section provides an overview of the vehicle’s electrical architecture. It is especially important for Battery and Enclosures, but less so for Cooling. Since Powertrain revolves around the mechanical integration of the electrical system, members should understand the fundamentals of how our vehicle’s electronics are structured.

Each major electrical system is broken into subsystems with defined responsibilities:

• Power Systems

  • LV (Low Voltage) → All low-voltage PCBs (e.g., power board, pump board, BBPDU).

  • HV (High Voltage) → High-voltage PCBs (e.g., VCU, Precharge, Motor Controller).

  • BPS (Battery Protection System) → Protection circuitry for monitoring and safety.

  • Power Generation (Array) → Array hardware and PCBs (e.g., MPPTs, Blackbody).

• Vehicle Controls and Telemetry (VCAT)

  • Controls → Driver input circuitry (dashboards, pedal board, control software).

  • Telemetry → Sensor circuitry and data transmission (battery, dyno, Blackbody).

  • Tracksim → [TODO: description needed].

• HV (High Voltage) → ~120V system; DC from the battery, AC from the Motor Controller.

• LV (Low Voltage) → ~24V system; powers electronics and PCBs.

• Fuse → Safety device that opens the circuit during a current spike.

• PCB (Printed Circuit Board) → Flat board with electronic components (chips, resistors, capacitors).

• Connections → Linked via wires; standardized four-corner M3 screw hole mounts.

• Key signals → Power, Ground, and Signals.

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A wire harness is a bundle of wires with connectors at both ends.

• Interior harnesses → Connect PCB to PCB inside enclosures.

• Exterior harnesses → Connect panel-mount connectors; typically have multiple insulation layers for protection.

Key Terms:

• Shielding → Grounded conductive insulation to prevent EMI.

• Connector → Plug or receptacle interface.

• Panel Mount → Receiving connector mounted on enclosures (waterproofing).

• Insulation → Protective layer around wires.

• Protocol for serial communication between PCBs.

• Two-wire system → CAN High & CAN Low.

• Allows node-to-node communication without a host device.

• PCBs are connected on a CAN bus (loop).