Electric Longboard Experiment: 3D Printing Off-Road Tires and a Boost Converter Battery Pack
Hi there, as you might know almost one year ago I created this simple yet powerful electric longboard. During the video I demonstrated that it drives without any problems and while doing so it reached a speed of 30km/h and achieved a range of around 7km. So all in all this electric longboard is not bad, not bad at all but that does not mean that you cannot improve it.
For example the wheels of the board are made up of pretty stiff plastic which is also rather smooth. The consequence is that the wheels do not offer lots of springiness against bumpy roads and they also do not feature lots of grip for off-road tours. Another example is the rather low capacity battery pack with 108Wh that can power the board with me on top for only around 7km.
A solution to the latter problem could be those 4 big lithium iron phosphate cells that I originally ordered for my garage Powerwall project but never used. Those could theoretically power the longboard for a distance of whopping 80km. A solution for the wheel problem could be this flexible TPU filament whose shore hardness is similar to that of rubber tires.
So in this video let’s find out whether I can use 3D printed off-road tires and whether I can use my lithium iron phosphate batteries as a longboard battery pack. Let’s get started!
This video is sponsored by [Insert Sponsor Here].
I even wired it up in a pretty heavy duty way by using thick wire, wire ferrules and cable lugs but just as I was getting closest to finishing the wiring I realized something. Such a boost converter cannot feed current back to the battery when the regenerative breaking function of the longboard is being used which means I would have to disable it.
But by doing that I obviously have no way of breaking which is something I did not want to risk so I pretty much abandoned the plan of boosting the voltage. Nevertheless we can still test the battery pack for which I firstly covered it in strips of duct tape for stability and insulation reasons and then I shoved it into my backpack before heading out for a proper test, here is what happened.
So sadly my battery pack didn’t work for this application but if you want to do something similar crazy then I would recommend getting 8 smaller still huge battery cells in order to increase the voltage in a safe way. But anyway I hope you still enjoyed watching my electric longboard experiment and learned something new.
If so don’t forget to like, share, subscribe and hit the notification bell. Stay creative and I will see you next time.
WEBVTTKind: captionsLanguage: enHi there, as you might know almost one yearago I created this simple yet powerful electriclongboard.During the video I demonstrated that it driveswithout any problems and while doing so itreached a speed of 30km/h and achieved a rangeof around 7km.So all in all this electric longboard is notbad, not bad at all but that does not meanthat you cannot improve it.For example the wheels of the board are madeup of pretty stiff plastic which is also rathersmooth.The consequence is that the wheels do notoffer lots of springiness against bumpy roadsand they also do not feature lots of gripfor off-road tours.Another example is the rather low capacitybattery pack with 108Wh that can power theboard with me on top for only around 7km.A solution to the latter problem could bethose 4 big lithium iron phosphate cells thatI originally ordered for my garage Powerwallproject but never used.Those could theoretically power the longboardfor a distance of whopping 80km.And a solution for the wheel problem couldbe this flexible TPU filament whose shorehardness is similar to that of rubber tires.So in this video let’ find out whether Ican use 3D printed off-road tires and whetherI can use my lithium iron phosphate batteriesas a longboard battery pack.Let’s get started!This video is sponsored by Altium.I recently switched to their Altium Designersoftware in order to create a schematic formy guitar effects board and I have to saythat it is a pretty good piece of software.It comes with everything you need to createa schematic and what I really like is, thatyou can search for components from onlinesellers which makes sourcing components foryour project super simple.So feel free to test the Altium Designer byyourself by following the links in the videodescription.Let’s start off with the simpler task bycreating off-road tires.For that I simply measured the diameter andwidth of one wheel which was around 83mm and46mm.My idea was to basically create a sleeve forthe 4 wheels from the TPU filament which willadd additional 4cm of diameter to the wheels.Now creating the basic shape of such a tirewas pretty simple to do in Fusion 360 butthe difficult question was what kind of patternI should add to the contact area with theroad in order to increase the grip.After thinking about it for quite a whileI went with long and short lines with a depthof 2mm.So it was time to import the model into thePrusaSlicer software in which I increasedthe perimeter value to 4 in order to get thickerand thus stronger walls for the print.For the filament settings I firstly triedusing SemiFlex or FlexFill 98A and after slicingthe model successfully with an infill of 15%,it was finally time for 3D printing whichdid not work out ideally.As you can see the filament did not extrudecontinuously and I could hear water vaporizingwhich means that the filament was simply toomoist.So after 22 hours of printing the first tiredid come out successfully but certainly notwith the best quality.That is why I threw the filament role intomy oven and let it bake at 50 degree Celsiusfor 3 hours in order to remove the moisture.Afterwards the printing worked out much better,at least in the beginning because the endresult only featured a slightly better qualitythan the previous print.But after using different filament settingswith a higher temperature, the 3D printingfinally worked out and thus I at least gottwo high quality tires for the motorized wheels.So it was time to hammer the new tires ontothe old wheels but word of advice from myfuture self, make sure to use some two componentadhesive to keep them in place.Now the result so far did certainly not lookhalf bad but how does it perform on a bumpyroad; let’s ask the expertOk so far so good but how do the tires performoff-roadSoin conclusion the tires truly improve thedriving experience but next time I shoulddefinitely print them with more infill becausethe tested ones already fell apart after around5km of usage.But nevertheless let’s move on to the partof the video where I strap a 1.28kWh batterypack to my back.The reason is that after connecting all ofthe 4 lifepo4 cells in series through thehelp of the included connectors, washers,spring washer and screws; they simply hadthe perfect size for my old backpack.And since one of those cells also weighs around3.6kg, so 14.4kg in total, there is reallyno other way to carry them around on my longboard.But we are getting ahead of ourselves, becausewith this amount of energy near my body thatcan create a short circuit current of 500Awe should definitely think about safety features.The good news is that LiFePo4 is a lot saferthan for example LiPo or Lithium Ion whichyou can see for yourself if you watch thisvideo from GWL power.But we should still not directly connect itto the longboard; instead we should add afuse.I used such an 80A one which I secured tothe plus connector of the battery pack byshortening one of the connectors into whichI then drilled a new 5mm hole which I obviouslyused to mount the fuse in place.After then soldering a red and black 6mm^2wire to an XT60 connector whose solder connectionsI also covered with shrinking tube, I crimpleda cable lug to the red and black wire in orderto hook them up to the fuse and the minusterminal and just like that our crude batterypack was basically complete.Of course I charged up each battery cell individuallybeforehand with a constant current constantvoltage charging method, just like the informationof the cells stated.So for a first test I connected the batteryback to the longboard electronics and as youcan see the wheels do rotate but there isa problem we have to address.As you might know the maximum RPM of any BLDCmotor is dependent on the applied voltage.For example with my old battery pack thatfeatures a voltage of 25V, we can reach anRPM of 2720.But the new battery pack comes with a voltageof only 13V, which means the max RPM is only1440.Now you might be thinking, well that is nota big deal because the tires of the longboardnow feature a bigger diameter of around 11.5cmwhich means that even with such a lower RPMwe should be able to reach a speed of around31.22 km/hThe problem is though that with lower voltagesthe power of the motors also decreases soI was skeptical whether we could reach themaximum speed like this.A solution to increase the voltage would obviouslybe a boost converter and for that job I actuallyordered myself this beefy one which can takea max input current of 30A at 12V.I even wired it up in a pretty heavy dutyway by using thick wire, wire ferrules andcable lugs but just as I was getting closeto finishing the wiring I realized something.Such a boost converter cannot feed currentback to the battery when the regenerativebreaking function of the longboard is beingused which means I would have to disable it.But by doing that I obviously have no wayof breaking which is something I did not wantto risk so I pretty much abandoned the planof boosting the voltage.But nevertheless we can still test the batterypack for which I firstly covered it in stripsof duct tape for stability and insulationreasons and then I shoved it into my backpackbefore heading out for a proper test, hereis what happenedSo sadly my battery pack didn’t work forthis application but if you want to do somethingsimilar crazy then I would recommend getting8 smaller still huge battery cells in orderto increase the voltage in a safe way.But anyway I hope you still enjoyed watchingmy electric longboard experiment and learnedsomething new.If so don’t forget to like, share, subscribeand hit the notification bell.Stay creative and I will see you next time.
