Introduction: Electric Mountain Board
The goal was an electric conversion with minimum damage to the board and the ability to remove the system for standard riding.
Step 1: Parts and Tools
I tried to get as many parts as I could locally but most had to be ordered online. The prices are approximately what I paid. Total cost of the project not including the board was about: $350
Board: MBS Core 95 from MBS Mountainboards. $300
Brakes: MBS V5 Brake Kit also from MBS Mountainboards. $60
Motor: 24V 300W Electric scooter motor from my local scooter shop. $30
Sprocket and Chain: Scooter sprocket and #25 chain also from my local scooter shop. $20
Steel pieces: 16ga sheet steel, perforated square tube (14ga), perforated bar and two flat bars (14ga) from Lowes. $20
The batteries, charger, controller and throttle were all ordered from Monster Scooter Parts.
Batteries: Two 12V 10 Ah scooter batteries. $65
Charger: 24V 1.6 Amp XLR Battery Charger and XLR charging socket. $38
Controller: 24V 500W Universal Voltage and Speed Controller. $33
Throttle: Generic 4-wire thumb throttle. $13
Other parts: Wire, electrical tape, wire connectors, nuts and bolts, zip ties, tie down straps. $35
Hex key wrenches
Drill and bits
Jigsaw and blades
Chainbreaker - $30 from Monster Scooter Parts
Step 2: Mounting the Sprocket
The MBS brake system comes with the mounting hardware (screws and spacers) needed to mount the sprocket to the wheel.
I used the pattern from the brake rotor to drill holes for the mounting screws into the sprocket. The initial holes were then widened to allow the mounting screws to sit flush against the sprocket.
Step 3: Installing the Support Bar
After measuring from the rear foot strap bolt I cut a notch in the support bar big enough to fit over the truck. The sides are bent up to create the gap. The left flap should be removed to make room for the brakes later.
A longer bolt the same size as the foot strap bolt is used to connect the support bar to the board. Rubber washers and padding are used to prevent scratching.
The upper bar and lower bracket were installed so that they did not scratch the board or interfere with the future position of the motor. The upper bar is solid steel to prevent bending at the notch and the lower bracket is perforated steel allowing it to more easily be bent around the truck.
Step 4: Mounting the Motor
Using the sheet steel I cut a rectangle so that it could be bolted to the support bar with enough room for the motor to fit between the two bolts.
The motor was then positioned on the sheet to align the two sprockets and the holes were marked for the motor mounting bolts. Once drilled the holes were lengthened to allow minor adjustment of the chain tension.
Two pieces of solid steel bar were drilled and used as brackets to lock the motor to the support bar.
Step 5: Wiring, Throttle and Batteries
The controller comes with a paper describing the connectors and wire colors. Most controllers are similar and this diagram shows a good example of connector wiring: Controller wiring diagram
The only difficulty was with the throttle which had 4 wires but only 3 on the controller. After some testing the 4th wire was used as a power on indicator and I connected it to the red wire of the power light connector.
Using pin connectors and female blade connectors I replaced the originals and added an on/off switch in place of the key connector. (I also transferred the labels to the new connectors)
The motor wiring had to be reversed to make the motor run counter clockwise so the board would not run backwards.
The thumb throttle was placed on the end of the brake handle after removing a rubber cap. The throttle wires were then fed down through the handle and sleeve following the brake cable.
Two 12V scooter batteries are wired in series to provide 24V to the controller and mounted to the middle of the board using small tie down straps. This PDF file is very helpful and shows how to wire the batteries: Battery Wiring Diagrams
Step 6: Brakes
The brake installation instructions and parts descriptions can be seen in this PDF: V5 Brake Manual
The brakes were installed according to the instructions provided with very little modification. The sprocket is used in place of one of the brake rotors and the cap that tightens the left brake pad had to be replaced to provide more room for the arm to move.
The controller is attached to the deck at the spot where the brake leash is normally connected.
Step 7: The Chain and Finishing Touches
Once everything is together the chain can be broken down and sized to fit. Chain tension is very important or the chain pops off whenever you try to turn.
This was the most difficult part of the whole project. A lot of trial and error was used to get the tension correct. I tried several ways to keep the tension even including using springs and rollers but in the end found it was easiest to just keep the chain short and tight.
When measuring the chain to take out links you have to stand on the deck because the weight of the rider pushes down on the support bar and moves the motor closer to the sprocket.
I used zip ties to keep all of the wires neat and put the battery wires inside the Velcro for the foot strap to keep everything out of the way. I also put a furniture cap on the end of the support bar to cover the sharp edges.
Step 8: Project Notes
Total time to put this together was about two days and then several more getting the chain tension just right.
I'm not sure of the battery duration or range but I have ridden it for up to 45 minutes without having to charge it.
If I had it to do all over I think that I would have made it just a bit faster. Its still fun the way it is though.