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  • Big Dyno Beginnings - Bayley and I have been thinking about building a bigger motor dyno for a while now, based off the same power system as the Big Kart. Over the last year we...
    10 hours ago

December 2, 2013

All Terrain Scooter Redux

The original version of my all-terrain electric scooter suffered from a number of problems, the most important of which was in the motors I used.  The triple CIM motors were just not capable of providing both the top speed and acceleration I wanted out of the vehicle.  Actually they could, but just not for very long before the insulation on their windings turned into a melty black mess.

After some attempted snow-scootering during the northeast snowstorm last year, I decided I was sick of the freshly roasted motor smell, and stored away the scooter until the summer.  A full teardown of the scooter revealed enough unnoticed or impending failures that I decided to scrap pretty much the entire mechanical end of the original scooter.

Version 2 features the same HobbyKing LiPo battery pack and Kelly 72V 200A brushed motor controller as the original, but nearly everything else is new.  Replacing the CIMs are a pair of Magmotor S28-200's, which are slightly larger than the S28-150's of battlebot fame.  Like before, the motors are mechanically coupled to one output shaft through a gearbox reduction, and connected electrically in series.

This version also has even bigger wheels (because the old ones clearly weren't large enough...), and over a foot of clearance everywhere.

The scooter's build log can be found here.

"Lefty" type leading link fork, for no better reason than that I like how they look:

This version of the scooter also fixes the chain and chain tensioner problems of the previous version.  A pair of connected sprockets at the pivot of the rear swingarm ensure that chain length remains constant over the travel of the suspension.  This way, I don't need to use any sort of chain tensioner.

The shock absorber on the rear swingarm is a very fancy downhill mountain bike part.  It is extremely adjustable, and damping in compression and extension directions are independently adjustable.

Here are the dual magmotor S28-200's.  Right, now the Kelly controller is limited to 100A at 60V, meaning that each motor gets 100A at 30V.  This works out to an acceleration of .54 g (at half the controller's current limit...).  This acceleration is only actually reachable if you lean way over the handlebars.  As I have experienced, you are simply thrown off if you throttle hard without doing this.


  1. Your Projects and your website is so awesome! Wish I could build all that stuff :)

  2. Do you have a video of someone riding this off-road scooter?