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Advise needed for mounting a drive wheel to a Flowboard. Kit suggestions?

Hello, I am planning to mount a internal hub drive wheel to the back of a Flowboard, a type of skateboard with 14 wheels mounted on two curved axles. The wheel would be mounted on a swing arm with springs connected from the swing arm to the tail of the board to apply downward wheel pressure and to allow movement of the wheel up and down. The board leans up to 45 degrees into turns so the tire should be curved for optimal contact with the concrete.

I would like to mount the battery and controller on the bottom of the board if possible. If there’s not enough clearance I think carrying the battery in a backpack could work. I would also like a pistol grip wireless speed controller if possible. I want it be capable of speeds around 20 mph with the ability to climb moderate hills. 

Any advice on the best kit/package for this project would be greatly appreciated.
Thanks! Morgan

The speed that a direct contact or friction drive motor produces is easy to calculate because whatever speed the friction wheel runs at the drive wheel will run at the exact same speed. So for calculating top speed and drive roller size, a 1 to 1 gear ratio can be used.

A 500 Watt motor can propel a light electric vehicle to 20 MPH on flat ground, and a 750 or 1000 Watt motor can be used for top speeds of 25 MPH.

Here is a gear ratio and drive roller size for a 500 Watt 2500 RPM motor and 20 MPH top speed.


And here is the calculation for a 1000 Watt 3000 RPM motor and 25 MPH top speed.


Please let us know if you have any questions.

Thank you for the gear ratio conversion. So I hooked up the new speed controller and throttle to the e300 motor. I was confused about how the wiring for the reverse polarity of the charger port should go. The way the new wiring harness plugged in caused a red wire go to a black and vise versa, which seemed counter-intuitive to me but word 'reverse' is sort of self explanatory. I tried searching for a schematic or conversation that might clarify it on your website and ended up getting blocked from the tech support page. 

I decided to plug the charger port in as it was and when I flipped the switch ON there was no illumination but the motor would rev. So I took the Flowboard for a ride and it worked fine. Then I plugged in the charger and there was no light emitted. When I unplugged it the motor started running. I flipped the power switch off but it kept running. I pulled the brake lever and that killed the motor but while I was fumbling to unplug the motor I started smelling something burning. In the act of trying to unplug the motor with one hand I managed to yank off one of the wires connected to the battery and was able to let go of the brake lever. 

I realize I'm getting an education in electronics here. Can you tell me what I might have done wrong? Was the charger port not supposed to have the wires reversed? The smell of burning electronics has me worried I may have fried the speed controller and or motor. Do I need to buy a meter to diagnose the damage that  may have been done?

Thanks! Morgan.

I am very sorry to hear about this. I have miswired and burned out many controllers and chargers so I know how it feels. I wish that I could say it gets better over time however even after installing controllers for over a decade I still occasionally make wiring mistakes and burn out parts.

The polarity between the E300 charger port connector and the SPD-24500B controller's charger port connector are in reverse of each other so reversing the terminals in one of the connectors is necessary to make their polarities identical (red wire to red wire, and black wire to black wire).

In most cases when a battery charger is connected to a controller in reverse polarity, the battery pack will overpower the charger and not allow current to flow in reverse and damage the controller. If there is a power switch between the controller and battery pack and that power switch is off then the charger could feed reverse polarity to the controller and damage it though.

If the motor is continuously running when the power switch is on without the throttle being engaged then that is usually caused by the controller or throttle. To see which part is causing the problem, unplug the throttle from the controller and turn the power switch on. If during this test the motor runs then the controller is faulty, and if during this test the motor does not run then the throttle is faulty.

A multimeter set to DC Volts could be used to test the battery charger and see if it is working. If the charger is working then it will output Voltage. If it does not output Voltage then it is faulty.

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