Spring Fall 2021 Onboard - timeline
The project will last for three weeks following ThursdaySaturday, May 13thSept 18th, 71:30 00 PM check-in
Week 1 | Go through readings and videos to understand battery systems
End of week 1 | ThursdaySaturday, May 20thSept 25th: Bring questions about readings to check-in for Micah and previous members to answerhelp with!
Week 2 | Continue readings and begin Steps 2 - 5
End of week 2 | ThursdaySaturday, May 27thOct 2nd: Bring questions about readings to check-in for Micah and previous members to answer help with!
Week 3 | Complete Steps 2 - 5
End of week 3 | ThursdaySaturday, June 3rd: Micah does a Oct 9th: Have steps done and Micah can walk through of the solutions :))
*Remember to ask questions to Micah or Owen whenever you feel stuck!
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We’ll start with a simple pack - here are some of the specs that we want for this project:
Item | Spec | Notes |
|---|---|---|
Amount of Energy Stored in pack | 100Wh minimum | We also want minimum weight while meeting this criteria. Minimum weight is a hard requirement (must be met). |
Cell Nominal Voltage | 3.635V | |
Cell Nominal Capacity | 3450mAh | |
Operating Voltage | 6-18V | Must stay in this range for the entire discharge. At any charge state (from fully charged to fully discharged, the pack voltage should be more than 6V and less than 18V). |
Single Cell Min, Max Voltage | 2.5V, 4.2V | At the full charge and full discharge limits |
What do you recommend for the number of cells in series and parallel, and why did you choose those numbers - we’re looking for an answer in the form of XPYS, where X is the number of cells in parallel and Y is the number of cells in series, along with a justification.
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Now that you should know how to design a battery pack, we’ll get you to run through the process of choosing a battery configuration for a car, given the following parameters (chosen to loosely represent Midnight Sun XIV):
If you think there’s info missing here, message Micah Black on slack and I’ll first make sure I didn’t make a mistake in the info provided, and then help you out to make sure you’re on the right track!
Car Specs:
Item | Spec | Notes |
|---|---|---|
Race Distance | 3000km | |
Car Average Velocity | 60km/h | Assume average velocity for the entire duration of the race, and that the path is flat. |
Power Consumed travelling at Average Velocity | 1005W | Per Motor |
Peak Motor Power | 5000W | Max power that the motors will draw (per motor) |
Number of Motors | 2 | Motors on each of the 2 rear wheels |
Motor Controller Min, Max Voltage | 50V, 165V | |
Single Cell Min, Max Voltage | 2.5V, 4.2V | At the full charge and full discharge limits |
Nominal Cell Voltage | 3.635V | Average voltage of a cell over the full discharge curve |
Single Cell Capacity | 3450mAh | Assume all cells are perfectly balanced |
Max Discharge Current of Single Cell | 10A | |
Solar Power Input | 800W | Assume the sun is always shining for the entire duration of the race |
What do you recommend for the number of cells in series and parallel, and why did you choose those numbers - we’re looking for an answer in the form of XPYS, where X is the number of cells in parallel and Y is the number of cells in series, along with a justification.
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