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By Jerome, August 18, 2010 4:51 pm

So I got my batteries and my charger. It took 6 days. I still paid $57 of shipping!!! ( I was a heavy package, around 4kg (8.8lbs) )  That charger is huge. I can charge four 22.2V(6S) battery at once! That is really nice! My 250W can give 13A at 12V. I will measure with my multimeter see if the charger can deliver that much. I have to be careful because the fuse of my Fluke is 10A!

I just tested the scooter with one battery and I am more then happy with the speed! I hit 30km/h (18-19Mph) which is perfect!

I have a nice video and great data. I am writing a post about it.

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By Jerome, August 16, 2010 10:48 am

I was surfing the web and saw this neat balancing electric scooter. It is created by Ryno motors. Here are some videos:

Here are the specs of the prototype
Range Up to 30 miles
Max Speed 25 mph
Recharge Time LiFePo4 1 ½ hours
Tire Diameter 25”
Weight of Bike 125 lbs.
Footprint 16” x 34”
Max Hill Incline 30%
Max Rider Weight 250lbs
Turning Radius Zero to 3 ft.
Estimated Retail Cost $3,500

You can find more informations on there website
http://rynomotors.wordpress.com

This looks like the Bombardier Embrio concept. The Embrio has smaller front wheel that acts like a stability control when the Embrio is stopped or traveling below 12mph.

Or the Canadian Benjamin Poss Gulak, with his one unicycle with two wheels.

Here is the new U2 version. It is a hybrid between a motorcycle and what you see there. I opens like scissors and unfolds into a motorcycle. (Not really like scissors, more of a  linear motion)

I just notice that Ben has a blog! http://bpgulak.com/

He his working on this neat track scooter call DTV.

Thanks to Hung Chang for is cool blog wackyboards where I learn about Ryno motors. http://wackyboards.blogspot.com/2010/08/ryno.html

PS- It is RYNO motors and not Rhino like the url

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By Jerome, August 10, 2010 12:49 pm

I just finish my finals! I have a few weeks off before my next intership.

I have a tonne of video to upload because I have been using the scooter a lot!! I have a couple of miles on it. I broke the belt a couple of time and I am right now waiting for a new belt, got 2 this time.
I am also working on a belt tensionner, I realise it is important (but to lazy to build one) since the belt slips a lot due to high torque when starting the scooter.

I bought these new Turnigy Nano-Tech battery from hobby king.

Here are some of the highlight

• Fast charge capable, up to 15C on some batteries.
  Longer Cycle Life, almost double that of standard lipoly technology.
• Internal impedance can reach as low as 1.2mΩ compared to that of 3mΩ of a standard Lipoly.
• Less Voltage sag during high rate discharge, giving more power under load.

Since V = RI, and we have a 3mΩ resistance per cell  in my standard battery and consume 80Amp at peak.

When you have 14,8V, that is 4 time 3,7V cell. Since they are in series, we should then have a 3mΩ * 4 = 12mΩ for a pack.

V = 0.012A * 80
V = 0,960V of drop out. (960mV)

With the 1.2mOhm
V = 0.0048A * 80
V = 0,384V of drop out.   (384mV)

There is a difference of 576mV. 40% difference.

That is theoretical, how does it stand up in real life?
Here are the measurement I got from live test.

82.51A Peak Amp
Nominal Voltage 16.52V and the minimum voltage sag was 15.58V

16.52V-15.58V = 0.940V
0.940V/82.51A = 11.393mΩ

77.83A Peak Amp
Nominal Voltage 15.65V and the minimum voltage sag was 14.71V

15.65V-14.71V = 0.940V
0.940V/77.83A = 12.078mΩ

81.04A Peak Amp
Nominal Voltage 16.67V and the minimum voltage sag was 15.37V

16.67V-15.37V = 1.3V
1.3V/81.04A= 16.041mΩ

72.85A Peak Amp
Nominal Voltage 15.23V and the minimum voltage sag was 13.95V

15.23V-13.95V = 1.28V
1.28V/72.85A = 17.57mΩ

70.03A Peak Amp
Nominal Voltage 15.98V and the minimum voltage sag was 14.88V

15.98V-14.88V = 1.1V
1.1V/70.03A = 15.708mΩ

I realise after looking at those results that in some test I have the initial voltage and some the “after the ride” voltage. That make my result not consistent and semi false.

There is difference between the voltage read at the beginning of the test and the one at the end. In my notes I had some results where I am not sure it that is the voltage are at the beginning or the end of the ride.
I will be careful during my next test.

There is many test to be done again with the new batteries. Can’t wait to see if I spend to much money on those batteries!

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By Jerome, July 23, 2010 6:00 am

When I was in Calgary doing my intern at Solarbotics, I when to this store called Power in Motion that specialize in urban electric transportation.  They had this neat demo wheel of the inside of a hub motor.

Here are the hall effect sensor. There is 3 sensors.

Here you can see the slot inside the shaft where the wires can travel.

There was also this neat battery. 48V 10.5Ah lithium battery. It weight 3.4Kg (7.5Lbs)

That could fit in my scooter. The only draw back of those specific battery is the continuous current discharge. It is very low. I think it is 2C so 20Ah… the motor consume about 4Ah with no load and I get surge current of 70Ah.

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By Jerome, July 16, 2010 6:00 am

Hello everyone,

Here is the work on the new revision of the original scooter. The original scooter is very small in length (29 inch). To select the new size of the new scooter, it was really easy. I just place my feet on the ground at a distance that I felt good and stable. Like on a snowboard.  So I added around 11 inch for a total of 40 inch (wheel to wheel).

Here is how I did.

This is the frame I found at St-Eustache flea market, one of the biggest in Québec.  I paid 10$ for it. Just the frame no motor, no battery. They are in very good condition and normally, when found online, they cost 18$ for the front wheel and 20$ for the back one. So 10$ was a good deal.

I have to go again to that flea market this summer! I will bring my dad, he loves flee market just like me!

Saw the entire frame in 2.

I also made 2 of  those plate you see in the picture so I can give tension on the belt with the left end screw. When I turn the bolt, the washer (big circle)  is move to the left, it pulls the axle of the back wheel.

To have a longer frame, I will use aluminium  L bracket. To mount them to my scooter, I drilled hole in the frame.

Here I cut the L bracket.

I also added other metal bracket to hold all the electronics in the middle of the frame.

Here is the progress. It feels stables when I get on it.

The new 11 inch makes a huge difference!