First Track Day!

Lab Note #4
Nov 10, 2014

Hello Viking Motorsports Electric race car supporters!

First, thanks for all of your support along the way.  We've got great news: after the project began a year and four months ago, we had our first track day at Portland International Raceway.  Most of the team got to drive the car, the power draw on the batteries was much less than we had calculated at an average of 50 amps instead of 210 amps, yet the car still went very fast.

This link is to a video of one of our better runs:  

Track day testing

The motor and controller are capable of delivering up to 320 ft-lbs of torque!  For comparison, a Dodge 3.6 liter V6 delivers 268 ft-lbs of torque, and a 5.7 liter V8 delivers 410 ft-lbs of torque.  

The race car weighs approximately 1000 pounds with a 180 lb driver in it, and we were able to drive 160 ft-lbs through the motor.  The tires did spin at times, and the data collection was very exciting!  For these racing slicks, they perform best when they are hot, and that requires a dry track.  The track started out damp in the morning, but dried out in the sunny afternoon, allowing for some pretty high quality test data.  

We had telemetry from the car's vehicle control unit that sent wireless data to a receiver laptop in the pit, so we were able to read torque, voltage, temperatures, current draw and regenerative braking current as it happened.  The motor did not require any cooling, and the water-heat exchanger cooling system was plenty to keep the controller cool as well.  

The car showed to be very durable, and lasted most of the day.  Our charger was working well, and PIR has a charging port for both 120V and 240VAC.  However, our high voltage cutoff software was not working properly, so we just turned off the charger manually with the circuit breaker on the charger.  

Below is a graph of our data from a couple of runs.  As you can see, we have some negative power, that is the regenerative braking power of braking the motor, turning it into a generator and reversing the current, sending current back into the batteries.  

At the end of the day, we did blow some low voltage fuses from the 12V battery.  The fuse box was loose and the positive terminal was very close to the chassis, we suspect this is likely the problem, and it is easy to fix.  

We are one of roughly 15-20 teams in North America with a drivable electric race car, and it is a very exciting time for our race car team.

Thank you,

Quinn

Formula Electric Manager

Portland State Viking Motorsports

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