Solar Car Design

1
Solar Car Design

• Any intelligent fool can make things bigger and
  more complex... It takes a touch of genius - and
  a lot of courage to move in the opposite
  direction.
• -Albert Einstein

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Keep It Simple!
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Key Ideas To Focus On

• Safety
• Is this safe?
• Reliable
• Must first finish the race.
• Efficient
• Performance Considerations.
• Execution
• Can we do it?

4
Process

• Learn general solar car concepts
• Spends time observing successful executions
• Read Event Rules!
• Work on design
• Read Event Rules!
• A lot of design problems and considerations can
  be solved simply by applying the constraints
  found in the rules.

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Overview

• Array Position
• Wheel Layout
• Frame
• Suspension
• Electrical

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Array Position

• A Few Concepts
• Above Body
• Body Contour
• Below Driver's Head/Canopy

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Array Position

• Above Body
• No Shadows from Driver or other components.
• Design Freedom below array

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Array Position

• Body Contour
• Aerodynamic
• Shaded by General Shape of Car
• Many Angles to sun

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Array Position

• Below Driver's Head
• Shaded by any items above array
• Can be bright for driver
• Driver is exposed to more direct sun without
  canopy

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Flat Array vs. Curved

• Flat Solar Arrays
• Easier to execute
• Angle to sun less of a concern
• Curved Solar Arrays
• Higher the angle the greater chance for breaks
  without ideal support.
• Angle to sun more of a concern
• Power Tracker Considerations

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Hybrid Array

• Increase overall array efficiency by placing
  higher efficient cells in most optimal position.

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Wheel Layout

• 3 Wheel
• 2 in front
• 1 in front
• 4 Wheel

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3 Wheel Layout

• 1 in Front
• Generally less stable
• Unstable in most turns at decent speed

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3 Wheel Layout

• 2 in Front
• Generally Stable
• Gets it done
• Popular

15
4 Wheel

• Possibly heavier than 3 wheels due to extra
  suspension
• Potential to provide better support and ride
• Road Debris benefit

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Frame

• Space Frame
• Triangles
• Usually welded metal
• Aluminum
• Steel
• Tub
• Usually composite
• Carbon Fiber
• Fiberglass
• Tube-like shapes/sections

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Frame

• Space
• Must be designed to support all necessary loads

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Frame

• Tub/Composite
• Lighter
• Stronger
• Easier to design
• Harder to execute
• Higher cost

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Important Cargo

• Driver
• Batteries
• Suspension mounts
• Array mounts
• Motor/Motor controller

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Suspension

• Do you need one?
• Not necessarily.
• Good idea?
• Solar Cells are fragile
• Road Debris
• Driver Comfort and ultimately Driver Safety

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Suspension Types

• Double Wishbone
• Popular
• MacPherson Strut or McPherson strut

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Suspension

• Double Wishbone

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Suspension

• MacPherson Strut or McPherson strut

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Electrical

• All solar cars are electric (battery) cars with
  an added array.
• All solar car main electrical systems look
  schematically the same.
• Difference is in the details and execution.

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Electrical

• Solar Cars are cars first, battery
  powered/electric cars second, and solar cars
  third.

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Electrical

• Power Trackers
• Converts and optimizes array power for system.
• Not needed, but a good idea.
• High cost.
• Power Tracker for each array string/angle, or one
  large Power Tracker for the whole array.

27
Electrical

• Fuses
• Specific Fuse Detailed by Event Rules.
• Add fuses where it makes sense for added safety.
• Switches
• Specific Switches Detailed by Event Rules.
• Add switches when it makes sense for added
  safety.

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Electrical

• AC vs. DC
• We're working with DC.
• Make sure components are DC rated for your
  application.
• Contact manufacturer or trusted consultant to
  make sure your components will work reliably with
  your DC application.

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Electrical

• Wire
• Size wire for worst case scenario.
• Temperature
• Voltage
• Current
• Wire should be capable of carrying more current
  than fuses at operating temperatures.

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Summary

• Keep It Simple
• Safe
• Reliable
• Efficent

31
Questions