Time to give an update on this project. The board was a pretty huge hit at maker faire in SF last year:

- Maker Rider.jpg (66.48 KiB) Viewed 5992 times
But it died right at the end of the show. On further inspection, we found that all the vibration on the skateboard deck had loosened one of the mosfet screws in the ASI controller, and the loose screw bounced around andshorted a pair of FET bodies together. Fortunately, a bit further down the road we made it to Method's place and he had all the tools and a new 4110 mosffet was all it took to be running again.
So the first real lesson is that vibration on an electric skateboard is brutal, and stuff that holds up fine on an electric bike can loosen and fail pretty easily on a board. We has some clue to this when the lumenator headlight stopped working earlier in the trip. It was mounted right to the deck with no damping and the vibration caused the header pins which link to boards together to fatigue and crack off:

- Fatigue Failed Lumenator.jpg (47.59 KiB) Viewed 5992 times
After these were fixed, we rode it around Vancouver just for kicks and also to take out to various events, but after hitting a railroad track at one point the motor just cut out and the ASI controller began blinking a fault flash code. This would be reset with a power cycle, but eventually it would happen more and more often until every sidewalk crack or pebble on the road would cause a controller shutdown. We went down a lot of wrong tracks trying to solve that one until finally on fully opening up the motors we saw this:

- Worn Off Phase Insulation.jpg (33.9 KiB) Viewed 5992 times

- Pitted End Plates.jpg (61.84 KiB) Viewed 5992 times
The mechanics of the motor had developed enough play that the end caps were occasionally rubbing against the stator windings, shorting them out every time they hit a bump, and that was causing the controller phase overcurrent faults.
So the 2nd lesson was that a homebrew inline wheel motor needs to be quite rigidly secured against side thrusts from all the impact forces that a wheel imposes. In this particular situation, I just hogged out more aluminum from the end plate so that it was about 1mm deeper, which improved the clearance to the windings and so far seems to have sorted this for now:

- End Plates Remachined.jpg (46.15 KiB) Viewed 5992 times
The final lesson involved overall clearances with stuff on the road. I had mentioned earlier that a rock in the road had severed one of the strain gauge sense leads:

- More Severed Hall Wires.jpg (35.38 KiB) Viewed 5992 times
Well the other problem with this design is that the motor body was only slightly embedded inside the wheel and was mostly exposed, and has gotten pretty dinged up. Any rocks more than about 1cm will hit the motor bell. From the outside there are a number of dents in the can.

- Dinged Up Motor.jpg (41.13 KiB) Viewed 5992 times
It hasn't done anything more than cosmetic damage yet, but ideally it would be nice if only the rubber wheels were in contact with the ground and road debris.
Previously competed in the Suntrip race on a
back to back tandem solar powered row/cycle trike. 550 watt solar roof, dual Grin All Axle hub motors, dual Phaserunner controllers, 12 LiGo batteries, and a whole wack of gear.
Now back in Vancouver learning to be a dad with my Big Dummy Frame (yes
This One, thanks ES!) with GMAC 10T rear hub motor, Phaserunner controller, and 52V 19Ah EM3EV pack
My website:
http://www.ebikes.ca
Please contact via email,
info@ebikes.ca, rather than PMs, which are disabled