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.

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!

First I had to draw everything on the computer, I printed it to be sure I had the perfect fit. This is the new scooter. Since my bracket is bigger I had to drill new holes in the frame. I took the piece of paper on glued on the frame.

I wanted to be aligned so I turn on my LED flash light.

Here are the new holes.

I did the same thing here, I glued down the drawing and punch out the holes.

Those are the bottom and top of the bracket.

The only concern I have is that I am wondering if I am loosing the natual air flow of the motor by putting the motor bracket right in front of the motor vent holes. I was thinking of drilling holes but need to be sure I will not make my new bracket fragile on the edge.

On the right side of the spacer you can see washers, there are 3 washers, they help me to adjust the depth of the motor so I can aligned the belt.

I am thinking of adding this fan to cool down the motor. I bought this 7 blades turbine fan on hobbyking. It is a little bit big put should do the job. I will need to machine a bracket to hold it to the motor.

I might try other solution like a 5V PC fan.

Today I tested the motor and it works! I test the 30$ motor and at high speed, it was making this very high pitch sound. I will probably need to adjust timing and frequency directly on the brushless controller.

I am concerned about the heat generated by the motor while free running. It was running at full speed with no load for a 2 minutes and it get warm. So a fan will be needed to ensure the magnet health.

Steps before first run

• Add belt tensionner
• Enlarge frame
• Wooden deck
• Throttle wiring
• Attach fan to motor

Here it is

That motor cost me 30$, so I bought 2. The original Rimfire motor is discontinued and was 99$

The first thing I did was take it appart! I knew that cheap motor like this one had to be inspected. I read that from different reviews on hobbyking that the majority of motor have there magnet falling off  (un-gluing).

After seen the above picture , I realise that I would probably need to add some epoxy!

On the left, is the 99$ motor and the right is the 30$ motor. That blue thing is glue, it looks like a epoxy, it is not like that around the entire motor. Only 1/4 of the motor. The 99$ motor has slot so the magnet slide in those slot. I do not have them with the cheap motor. Those slot and glue provide good strength.

On the left is the original motor.

While playing with that motor I realise something amazing! The part with the wire, the stator, can fit perfectly inside the brand new 30$ motor!

This is the stator, on the right you have the old one that I brooke, so there is not wire in it.

This is the old bracket, I will need to machine a new one. I am working on it right now.

The big difference between both motor is the quality of the magnet. (I think) When I remove the stator from the rotor, the 99$ motor offer a big resistance when I try to pull it out. I did not get the same type of resistance with the cheap 30$ motor. It was WAY more easy! I was suprised. The air gap seems to be the exact. (Airgap is the space between the magnet and the stator (coil)) So I guest the magnet are cheaper. I have no tools to measure the magnetization of the magnet. Maybe I could find that at my University…  (email sent)

BTW I ordered the real motor I wanted from hobby king! The TGY AerodriveXp 46 SK Series 50-55 580Kv / 1580w.

I am going back to finish up a new motor bracket. Can’t wait to ride the new scooter.  I will also modify the scooter: add 1,5 feet to the scooter. More on that later.

This is the review I left on hobbyking.com site

I really love this charger. The concept of KISS ( Keep It Simple Stupid ) is 100% there with that product!

The build quality is very good, all aluminium. Charging is sort of very simple and stupid proof. It was a 5Amp car fuse on the back. It has rubber feet on the bottom. Some solid silkscreen/sticker on top. It is bullet proof!

When you plug a 3 cell into the charger, 3 RED led will glow and then after it is finish, it will turn to GREEN.

If there is a bad cell, the specific LED will flash from RED to GREEN.

You can charge battery using what they call “parallel” charging. So you charge your 3 cell with only 2 wire at 11.8V instead of 3 time 3.7V.
You need special plug to do that.

The fans does make noise. It is not that bad but it makes noise.

The only thing that I don’t like is the 12V car adapter. I don’t want to cut it and will need to make my own socket.

After charging my 4 cell battery. I had
4.181V
4.203V
4.199V
4.184V

my other battery was
4.196V
4.209V
4.207V
4.180V

I highly recommend this charger!

Have fun!

The battery had good reviews so I bought them and they where really cheap. These are 14.8V 5Amp battery.  When charge, they go up to 16V. I will put 2 in series to get around 33.5V fully charged.

I had to solder some dean connectors on them since they came with 4mm gold bullet connector and I don’t use them in my scooter.

The connectors on the left are the deans connectors. I even took the time to put red and black heatshrink.