A light electric stand up scooter

[ferias77]

No, no CNC, only my hacksaw, my file and my power drill.
I push the scooter and I brake with the right foot. That's why I put the motor on the left on the scooter. So I think it won't raise any problem.
I soldered all my plugs and started the motor. It's ok, it works ! But the motor is not very well balanced...
I think your motor is ok for riding on the flat. Do you tried to climb a hill?

Eric

[walls99]

Salut Eric,

Nice work! how are you going to attached the sprocket to the wheel? do you have any picture?

Merci,
Laurent

[ferias77]

Hi Laurent,

The sprocket is attached to the wheel thanks to 2 spacers and 4 screws. I could have made a picture... but my laptop decided to die this week end... So I don't have more access to my CAD model... We can see the spacers on the pictures on the previous page. The 4 screws are fixed between the spokes of the wheel.

Eric

[nyx]

Hi all,

I am sorry for your laptop Eric, i hope you'll be able to finish your scooter without difficulties...
you're right, my motor is just enough for flat and very light climb... but that enough for me.

Since yesterday I have something strange on my scooter. I'll try to explain the problem :
so since yesterday for the same speed/power I have to put more throttle. for example before, for about 10kph and 200-300W, the throttle was at about 1/4. now for about same speed/power the throttle is more than 1/2.
I can push the throttle at 100%, I reach 45-50A. Before I couldn't push the throttle at 100% whitout pulling more than 50A.
Its not a real problem as now at full throttle, I can't burn the motor. But I hope the power will not reduce again, and i'ld like to know the reason...

I am sure its not the battery, I made a new test just after a full charge...
can it be my servo tester ? Or my motor which has lost power?

Thanks for help

[ferias77]

Hi,

My scooter is progressing... but not as fast as I would like, I would need 48 hours / day
I machined almost all the parts (with my hacksaw and my file ), it is ok. Photos soon.

And I installed the wattmeter, the controler, and the servo tester. I made the cables longer between the battery and the wattmeter, between the wattmeter and the controler and between the servo tester and the controler. With normal length cables, the start of the motor is very soft. With my longer cables, it is really harder, there is a "clack" when the motor starts. After, it runs very smooth. Any idea why ?

[ferias77]

Some photographs :

I machined the wheel in order to use the ball bearing to center the sprocket :





I machined the motor shaft to put the sprocket :





Next step soon !
Eric

[ferias77]

Hi,

That's ok, the scooter has made his first run !!!
Top speed = 37 km/h ! See the photographs and the video :







Eric

[adrian_sm]

Awesome. I so want to make one now.

Any plans to put a real throttle on it? I always found using the pot as a throttle on the servo testers pretty dangerous.

- Adrian

[An average human]

well done on your scooter

i think i should warn you about the length of the leads between your battery and esc and lack of capacitors on the input to your esc, i personally ran in to trouble with this issue http://endless-sphere.com/forums/viewtopic.php?f=28&t=17675

anyway good luck

[ferias77]

Awesome. I so want to make one now.
Any plans to put a real throttle on it? I always found using the pot as a throttle on the servo testers pretty dangerous.
- Adrian

I'm happy you like the scooter. I agree with you, the servo tester is very dangerous... I think I will buy the beta cycle analyst and use a hall throttle. It will replace the servo tester and the wattmeter.

well done on your scooter
i think i should warn you about the length of the leads between your battery and esc and lack of capacitors on the input to your esc, i personally ran in to trouble with this issue http://endless-sphere.com/forums/viewtopic.php?f=28&t=17675
anyway good luck

Thanks for the warning. I was aware there was a problem with theses long wires... I will look your link. I thought it was ok because I run 5S and the ESC is 6S max.

[adrian_sm]

Cycle Analyst is cool, but if you want to go cheap, you can make a simple mod to the servo tester to run a hall throttle.

I have done this, really simple.

viewtopic.php?f=28&t=12196&start=15#p313413

- Adrian.

[ferias77]

Cycle Analyst is cool, but if you want to go cheap, you can make a simple mod to the servo tester to run a hall throttle.
I have done this, really simple.
viewtopic.php?f=28&t=12196&start=15#p313413
- Adrian.

Thanks for the link !!!
I bought the same servo tester but without the aluminium case : http://www.hobbyking.com/hobbyking/stor ... duct=14774
I'm not sure to have well understood, and I would like to be sure...

I remove the potentiometer, I plug my throttle on the power supply of the servo tester, I connect the signal of the hall throttle to the center pin for the potentiometer, and that's ok? It is so simple??? I hope !

Eric

[adrian_sm]

Yep. Pretty simple. Here is a (corrupted) pic of mine.

[ferias77]

Thanks for the photograph Adrian. I will do it asap.
I would like having a thumb throttle and a button for cruise control. I have this button on my e-bike, and it is very usefull for long rides. I think the only one simple solution to have this cruise control is the cycle analyst, no?
I made other tests with my scooter to be sure it is ok. And no... Starting full throttle, I have to push on the handlebar, otherwise the front wheel stands up !!!
And I finished by coming to the limits of the machine : the pressure screw between the motor and the small sprocket in not enough. I have to work on this. I will too order a 35 teeth sprocket to limit the top speed : 26 km/h will be enough, 37 km/h is really too much. So there will be more torque during the start...

[adrian_sm]

You should be able to add a button fairly easily to hold it at a specific throttle posistion, ie full throttle. A momentary push button and a resistor should do the trick.

I have also used this little guy to smoothly ramp up the throttle, for a push button input. I just plugs in between the servo tester and the ESC. This was great for implementing a push button as a throttle, without flipping the bike.

http://www.hobbyking.com/hobbyking/stor ... oduct=8863


I have also got an Arduino based throttle interface I am working on. Just in the debugging phase at the moment.

It accepts a button input as the throttle, has a power or speed PID loop (users selectable on the fly via the button), a turbo mode, SD data logging, LCD display (speed, power, dist, wh/km etc), temp sensor, wheel sensor, voltage, current... can't remember what else. This is being purpose built for my frcition drive project, but it is looking like it will be very usefull for other applications too. : ) Not ready for release yet, but it is looking really good.

- Adrian

[ferias77]

Hi,

I bought this Turnigy speed regulator with my motor, but I don’t have tested it yet. I thought to a problem : it smoothly ramps up the throttle, but it smoothly ramps up down too, no? If it is the case, it is very dangerous… There is a solution?
For the button, I will try to draw something.

Eric

[adrian_sm]

Np. There is separate adjustment for up and down. So no problem.

Just try it on the bench first.

- Adrian

[fechter]

Great job on the scooter!

How hot does the motor get?

[ferias77]

Np. There is separate adjustment for up and down. So no problem.
Just try it on the bench first.
- Adrian

I tried it this evening, really great ! As it works, I won't need any thumb throttle : I will try with only a push button and a potentiometer to choose the top speed.

Great job on the scooter!
How hot does the motor get?

I didn't ride for a very long trip but I made a lot of stop and starts, and I think the motor temperature was about 35°C. Not too warm to the touch, but I don't have any thermometer. Peak Power was 1900W

Eric

[adrian_sm]

I will try with only a push button and a potentiometer to choose the top speed.

If you want this sort of setup. I would keep the standard servo tester, and use that to set the top speed. Then cut the 5V leg on the pot in the servo tester and put your button in the break. Then I think you need to add a pull down resistor between the signal leg of the pot and ground, so it makes sure it goes to zero when you let go off the button. Then off course use the speed regulator thing.

That should do the trick.


Oh. I have been meaning to ask. How on earth do you stop? Only brakes I saw in your video was your foot. That almost scares me as much as using teh servo tester on it's own as a throttle.

I still have a nagging urge to build one of these... urrgggh... must finish other projects first.

- Adrian

[ferias77]

If you want this sort of setup. I would keep the standard servo tester, and use that to set the top speed. Then cut the 5V leg on the pot in the servo tester and put your button in the break. Then I think you need to add a pull down resistor between the signal leg of the pot and ground, so it makes sure it goes to zero when you let go off the button. Then off course use the speed regulator thing.
That should do the trick.

I thought doing like that (I used your photograph, I hope it isn't a problem, otherwise I remove it) :



For example, if the potentiometer is 10 kOhm, U1 = 0.9 V and top speed = 5.4 km/h.
If the potentiometer is 0 kOhm, U1 = 5V and top speed = 30 km/h

It would be more simple with you solution. But I want to change the potentiometer of the servo tester to have the possibility to screw it on a mount. And it is hard to find a 5K potentiometer. 10K is more common. I don't understand very well the pull down resistor?

Oh. I have been meaning to ask. How on earth do you stop? Only brakes I saw in your video was your foot. That almost scares me as much as using teh servo tester on it's own as a throttle.

For the brake, I didn't mount it, but it will be the case for the next ride ! You're right, it is dangerous...

I still have a nagging urge to build one of these... urrgggh... must finish other projects first.
- Adrian

So I hope you will finish other projects asap !

[adrian_sm]

The pull down resistor is needed to make sure that when the throttle button/switch is open, that the U1 =0V. Otherwise it is floating, and current leakage in the PCB can make it go positive. So even without the button pressed, you can get a throttle signal causing the motor to start. Not good.

Just place your switch on the red 5V line at the top, not the black 0V line on the bottom, and R1 will act as the pull down resistor.

Too easy.

- Adrian

[ferias77]

The pull down resistor is needed to make sure that when the throttle button/switch is open, that the U1 =0V. Otherwise it is floating, and current leakage in the PCB can make it go positive. So even without the button pressed, you can get a throttle signal causing the motor to start. Not good.
Just place your switch on the red 5V line at the top, not the black 0V line on the bottom, and R1 will act as the pull down resistor.
Too easy.
- Adrian

Ok, thanks, perfect ! I will order the components and test it asap !

The new push button circuit :


Eric

[Grinhill]

Nice work Eric. BTW - Is there something wrong with your video, I couldn't play it????

And I finished by coming to the limits of the machine : the pressure screw between the motor and the small sprocket in not enough.

This is a fairly common problem, and the best solution found by recumpence and other forum members seems to be drilling a "dimple" into the shaft a few millimetres deep at the position marked by the grub screws. Works better than filing flats onto shaft. Also, on final assembly don't forget to use some Loctite thread locker on the grub screws.

[ferias77]

Nice work Eric. BTW - Is there something wrong with your video, I couldn't play it????

And I finished by coming to the limits of the machine : the pressure screw between the motor and the small sprocket in not enough.

This is a fairly common problem, and the best solution found by recumpence and other forum members seems to be drilling a "dimple" into the shaft a few millimetres deep at the position marked by the grub screws. Works better than filing flats onto shaft. Also, on final assembly don't forget to use some Loctite thread locker on the grub screws.

Yes, we have the same idea, I did it yesterday. I hope it will be enough...

For me, the video works very well. There was maybe a problem when you tried. Please try again and tell me if it works.

Eric