I’ve finally got my electric mountainboard up and running well. There have been lots of part revisions, lots of failures, and lots of learning. But this thing is sweet.
Note:
* I’ll try to get the design files for the 3D printed parts up and thingiverse tomorrow. I have to make one small tweak before they are fully ready. *
** 3D file links added below
* I’ll also try to make another blog post tomorrow with the build details of the board *
Photos
Videos
Sweet Twirly helmet mount footage
Decent forward looking footage
Parts
- MBS Atom 90 Board – $170
- Kenda K909 Tires – $70
- LiFePo4 Batteries – 2 4s 8400 mAh and 2 2s 8400 mAh wired as a 6s 16,800 mAh – $250
- Turnigy SK3 213kv Motor (2.5kW max output) – $70
- Hobby King 150A Car ESC – $70
- ESC Programmer – $5
- HobbyKing GT-2 Remote Control – $20
- 1000 mAh 3s LiPo for remote control – $5
- 3D Printed Motor Mounting Bracket and Wheel Inserts – $Free if you have a printer
- Flipping sweet LED strips lining the edge of the board – $10
- Turnigy Watt Meter – $40
- 11 Tooth Sprocket – $10
- 47 Tooth Sprocket – $16
- #25 Chain – $12
- #25 Chain Master Link – $1
- Chain Breaker – $20
- Couples meters of black and red 12 AWG Silicon Wiring – $5
- Bunch of male and female XT60 Connectors (The yellow connectors) – $10
- Couple of HXT 4mm Gold Connectors for the Motor – $2
- 4 ECO6 50W Battery Chargers + a 360W power supply – $100
- LED Cluster Headlight – $2
- Some servo extensions from HobbyKing – $2
- (3) 1/4″ diameter by 1/2″ long bolts for each motor – $1
- (3) 10-24 by 5/8″ long bolts to secure the motor to the mount – $1
- (3) 10-24 by 5/8″ long bolts to secure the wheel inserts together – $1
- M8 x 30 (or 35) bolt to secure the motor mount onto the axle – $1
- Hot Glue
- Double Stick VHB foam tape
- Battery Box – $5
Total Estimated parts cost for a 1 motor board: $900
Add another $200 for a 2 motor board so $1100 for a 2 motor board
Details
The top speed with my 6S LiFePo4 battery pack is 19-20 mph. With a 7S pack, I predict the top speed will be around 24 mph. 20 mph feels plenty fast to me though.
With my 6S 16,800 mAh battery pack, I am getting around 10 miles of range (driving up and down hills as well as flat ground) to a charge. I haven’t been the full range yet because it’s freezing outside, but I have been 6.3 miles on 9.5 Ah of discharge so 10 miles should be a good number to go by.
I’m pretty happy with how it goes together. All of the parts just bolt on (except for the LED strips and the ESC which are just hot glued on) so it’s easy to add to an existing board, or take everything off if you don’t want it anymore. Makes it easy to service everything.
It feels really nice to ride. Especially now that I changed to motor timing to high on the ESC. This gives much better acceleration. I still can’t get up real steep hills with just 1 motor, nor start from a complete stop (needs to be barely rolling for the ESC to function well). And I have to be pretty gentle on the gas otherwise the ESC loses sync with the motor and makes nasty noises. But now that I’ve ridden it a bit it works quite well.
This thing if flipping sweet to ride. People are bamboozled when they see you riding a ‘skateboard’ uphill at night with sweet LEDs.
I get about 45 minutes of continuous riding with my battery pack.
Room to Improve
I would really like to add a second motor and ESC to the other rear wheel. This would give awesome acceleration as well as decrease the load on the other motor. Would cost ~$150.
I have though about using 4 65 5000 mAh LiPo batteries (yielding a 20,000 mAh pack) to give me more range as well as being lighter. Would cost $200.
Obviously the wiring could be improved. Maybe a slot in the board. Or a plastic sleeve to run through.
Alien Power EV ESC. I’ve read a bit about these and they seem to have a lot more programming options. This could be nice, but not necessarily needed if I got a second motor.
I’d like to build my own ESC at some point. An Open Source high current ESC would be sweet.
Better charging. Currently I have to unplug the batteries from the harness and take them over to my charger. I would like to build my own charger that stays on the board so I could just plug in one plug and it charges away.
Also, in regards to charging, the chargers I have are only 50W chargers. They should really be 100-200W chargers to charge the batteries as fast as they can handle it. Takes about two hours to charge with just the 50W chargers.
Remote control. Tons of options here. Smaller would definitely be nicer. Get rid of the steering wheel. Have a deadman switch.