Crimson Racing Wiki

Power Distribution Module

Subteam: ElectricalSubsystem: Custom ElectronicsAssembly: Power Distribution AssemblyCars: CR21, CR22, CR25, CR26I, CR26E

Purpose

Distribute and protect power to every critical vehicle system, replacing conventional relays, fuses and control wiring.

Function

A MoTeC PDM15 with 8 x 20 A and 7 x 8 A outputs, with current monitoring and limiting on every output, controlled and monitored over CAN. Because it is CAN controlled it also expands the number of digital switch inputs available to both the dash and the ECU.

Design Process

Replacing relays and fuses removes a large number of connections and control wires, which is directly aimed at the historical connector failure problem. A CarTek PDM-4C is used as a secondary module for auxiliary or test-specific loads (4 x 20 A outputs with selectable current limits, CAN current monitoring, 0.28 lb, $325), powering the Podium Connect telemetry module and onboard cameras and replacing a previously needed dedicated battery.

Manufacturing Process

Board manufactured externally, populated and bench tested in house before it goes on the car.

Full Material List

Custom PCB with a machined or 3D printed enclosure.

Reoccuring issues

Shakedown 7-15-23, CR22. An injector was not receiving full 12 volts and the PDM output measured 4 volts. Continuity was checked between wires and the switch was found to be inconsistent, then soldered.

Properties

Operates below its 120 C internal limit in service; measured 75 C after an endurance event. From the cost report drawings and CAD: Manufacturer datasheet, MoTeC PDM15: Weight: 260 g; Case size: 107.5 x 127.5 x 38.7 mm. Source: Datasheet: CR22/Electrical/Design/MoTeC/USB Contents/Datasheets/14104 PDM15 datasheet.pdf Quantity per car, as costed: 1

Still to document

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