[SKATEway]POST 2

Hello every one!

So the challenge of this week was to finalize the choice about batteries and motors. And we did it. First we did again the motors calibration we need for our system. Last week we did simple calculations. Taking all parameters, we conclude that we need two 450w 48v motors. Plus, we choose a hub motor to the gain space. We had to be aware about the function of the engine. We made sure it is a two direction motor with the good controller. I contacted the seller and he confirmed this fact.

Here motor + controller : https://www.aliexpress.com/store/product/8-inch-450W-48V-brushless-non-gear-hub-motor-electric-scooter-electric-motor/1461770_32476560207.html

For batteries, again for gain space, we found batteries kit to build by ourself. One more avantage, its less expensive. LifePO4 48V 15Ah (http://evcomponents.com/diy-battery-kits/48v15ah-headway-lfp-battery-kit.html).

For the next week, finish the list of composents (accelerometer, board, led …). Begin the PCB of our system with Expedition PCB that I installed this weekend.

Have a great week!

Charles

[SKATEway]POST 1

Hello,

Once week after the beginning. Here is where we are.

This week has been used to fix the system’s calibration. In the last post, I determined some values, but I based them on existing projects. I made calculs by myself for more accuracy from existing data such as acceleration (a = 2 m/s²),  total weight (100 Kg), spoke of the wheel (r = 0.11 m), rotation per minute (63 ras/s) . To extract resulting data such as couple (C), motors power (P), 48V batteries intensity (I).

C = a * m * r = 22 Nm

P = C * w = 690 W

I = P/U = 15A

The coming week, will be used to identify exactly what components we would use. The main challenge would be about motors and batteries. For motors, hub or not? A hub is space gain but the power delivered by the engine is less than a classic motor. The space is also a problem for batteries. We have to find the most flat as possible. We have to choose betwen several kind of batteries (lithium, lithium-ion, lithium iron posphate, lead …) We need to determine the need. We must not oversize our system because the battery is the most expensive item of the project. If a simple lithium battery is enought, we won’t pick the last lithium iron posphate generation battery.

Ps : A picture to visualize our SKATEway (made by my mate Alban)

Charles

[SKATEway]POST 0

Hi,

I am Charles, and am working with my mate Alban on SKATEway, a new kind of skateboard.

This first week were used to think about the project and main specifications.

Its a skate board with three sections. One middle section fixed and two side sections mobile (like snake board), which can rotate. Two twenty centimeters wheels  on both sides of the middle section.

The skate should be used in urban environment. It would be very handy and with small size.

The skate is driven with the bodyweight. Tilt the body forward and backward to manage the speed. Tilt the side sections with the ankle to manage the direction, move to the right, to the left. (accelerometer sensor)

The main complexity is the machinery. How to build this, what kind of materials. What kind of engine power and batteries. It has to be resistant and support up to 100Kg

We can estimate a weight about 15Kg. supllied with two 350W motor for each wheel. Equipped with two batteries of 48V Lifepo4. Autonomy of One hour minimum planned. Max speed about 20Km/h

The estimate price is about 900€. We could reduce the price further with new knowledges.

New functions are comming to make it much more fun!!