Power Wheels Racer 2.0: Update 1

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Power Wheels Racer 2.0: Update 1

Jul 02, 2018

Andrew Barbosa


power wheels

 

Over the past several months us here at The Workshop have been designing and fabricating the next generation of go-kart for our entry into this year’s Power Racing Series event at the Orlando Maker Faire. During last year’s event we found the old kart to simply be too big, too unwieldy, and too slow. Our aim with the new kart was to improve on these three aspects. First, a new frame was designed and welded together. WE salvaged certain parts of the old kart including the steering system and drive shaft but upgraded them with a full wheel in the front (instead of the old handle) and a 48V brushless motor (instead of the old 36V Brushed one). We hoped that the increase in voltage and switch to brushless would allow the kart performance to stay the same or increase while also increasing our run time.

 

Speaking of run time, we decided to build a custom battery pack using some li-ion 18650 cells purchased on ebay. That pack was assembled using the Vruzend DIY battery kit. The kit worked fantastic and after a few days we had a new battery the gave us the 48V with increased capacity to help achieve our goals. Importantly this battery only needed one charger vs our last which required 3 batteries to be separately charged and took quite some time. 

 

After selecting our tires and other miscellaneous parts we were able to assemble the kart and begin testing of the system. This is where I discovered a plethora of issues and oversights that ultimately means the kart will be remade.

 

The Frame

  • The frame of the kart is significantly warped. Once we put the tires on the ground the front passenger side tire didn’t contact the ground and spun freely on the ground. If we pushed it down to contact the floor the rear driver side tire lifted up and spun freely. 
  • The frame is too long. Due to its length the turning radius is also too large ad wont be suitable for the style of track it’ll be raced on. 

 

The Brakes

  • While the brakes on the kart work (and work well at that) the brake pedal is no good and the brake caliper itself contacts the rear tire and will destroy it when we are racing with shifting weights on the tires causing them to expand. 

 

Motor Gear Ratio

  • To our knowledge the combination of sprockets used on the kart gave it a 6:1 gear ratio. Our motor, under no load, is rated to 1800 RPM which means we’d be getting about 600 RPM in a best-case scenario.

 

The Battery

  • The DIY batter does put out 48V as we needed but it seems to be incapable of providing the current we need for the system. Double checking the system with a store bought lipo battery confirmed the issue.

 

The ESC

  • I have no idea why this doesn’t work, and it makes me lose sleep at night.

 

The Steering

  • It doesn’t work.