A light electric stand up scooter

[ferias77]

Quick specs:

29 volt LiFePO4 battery; 8 inch pneumatic wheels; 63-64 230 kV motor; and 15/80 gear reduction ratio. It's a belt drive without a freewheel. Be sure to turn off the "brake feature" in the ESC.

Thanks for the information and the piece of advice about the break feature. Last information, which controler do you use?

I will order this evening to hobbycity. I will finally use the 63-74 170 kV motor with the 5S batteries of my electric bike. I hope it will work correctly with only 5S : they advise 6 to 10S on the Hobbycity website...
http://www.hobbyking.com/hobbyking/stor ... oduct=7870

with the Turnigy Brushless ESC 85A w/ 5A SBEC
http://www.hobbyking.com/hobbyking/stor ... duct=10331

and with a chain drive, but without a freewheel to begin.

The CAD design is almost finished, I will make pictures as soon as possible !

[ferias77]

The pictures :

[adrian_sm]

Beautiful renderings.

Gear ratio looks very low, what speed is it geared for?
Also looks like you won't have enough clearance for the chain. Especially if you plan on using the brake.

[ferias77]

Thanks adrian,

gear ratio = 2.5
10 teeth for the small gearwheel and 25 teeth for the big. The motor is slow and powered with only 5S.
I don't think making an error calculating the no load and top speed :
No load speed = 170 kv x 20V x 10 / 25 x pi x 125 mm = 32 km/h => 32 x 85% = 27 km/h for the top speed of the scooter on the flat.

With the power of that motor, it wouldn't be a problem to reach 27 km/h, even if I have only 5S. I made a mistake ?

I will verify for the brake and the clearance for the chain.

Eric

[nyx]

Nice Job Eric,
Adrian, i think there are enough room for the chain, but on the 3D view it looks like the brake will push one the chain/sprocket.

on my side i advanced the integration, as I didn't find a good id for my throttle, I integrated the Potentiometer.
The wattmeter is on the middle of the handlebar.

Soon new pictures, now i wait my 50mm fan and i have to find aluminium plate the hoods

[ferias77]

Hi,

There are 10.4mm between the wheel and the motor mount, and the chain is 7.4mm wide, so there are 1.425 mm each side.

There is no problem with the brake, but it is very close, so I will modify the motor mount in order to have more security.

Eric

[nyx]

Hi Eric,

1.425mm ( really accurate !!! ) is not Inevitably an problem. Between the chain on the freewheel and the scooter Frame, i have no more than 1mm. But as the motor is fixed on the frame, nothing moves so i didn't have any problem.
In your case, you would need a bit more as the wheel is not far, and you motor is not placed on the frame but on a support.

Yesterday I used once again my scooter. Its really pleasant, power is enough to run without getting tired. The motor is still not to much hot, so with my 50mm fan and an NACA air intake, it will be really good.

I have another question for the experts. I would add an switch for cutting off. for exemple when i go in the subway, i would cut off with this switch and not unplug any thing. But for that i will need to pass 50Ams max in this Switch. I saw some switchs which can cut up to 25Amps, in my cas i don't need to cut lots of Amps (when i cut the motor si stoped), could i use a such switch ? if else i could i do?

Thanks

Thibaud

[adrian_sm]

My preferred method is to just use a controller that has an on/off switch. Like this:
http://www.hobbyking.com/hobbyking/stor ... duct=10331

[nyx]

I don't understand. is there an switch on the ESC ? it looks to have the same features as my ESC :
http://www.hobbyking.com/hobbyking/stor ... oduct=2166

[adrian_sm]

Unfortunately it doesn't show it in the pictures or the description, but it actaully has an external switch.
Pleasant surprise when I got my first one.

Hang on, I'll take a pic of mine..... here you go.....

fr_950_size580.jpg (113.71 KiB) Viewed 1104 times

[nyx]

ok I prefere That so i don't have it on mine. but like that it doesn't cut the battery so the mattmeter is still powered. Anyway its an nice an easy way. I think i will begin without.

[nyx]

Hi all,

i Worked a bit on my escooter.
I managed to find an aluminium plate of 1.8mm, so I'll be able to make hoods.
I installed my wattmetter.
Finally i moulded the hood for protection of the chain and sprocket from my feet. I am happy with it.

Check pictures

Edit : I just ordered my 3S Lipo, an Turnigy nanotech 6000mAh

[ferias77]

Hi,

Thanks for the photographs nyx. I like the fiber protection for the chain.
I ordered the 6374 motor, the controler, the chain, the gearwheels and all the wires. I hope it will come soon
I think I will put the wattmeter on the handlebar, because the batteries will be in a backpack.

[adrian_sm]

You might be interested in this remote shunt mod for the watt meter.
http://endless-sphere.com/forums/viewto ... 76#p320027

- Adrian

[ferias77]

You might be interested in this remote shunt mod for the watt meter.
http://endless-sphere.com/forums/viewto ... 76#p320027

- Adrian

Thanks for this topic Adrian. I will try without modifying my wattmeter in a first time, and if it works, I will modify the wattmeter.

[ferias77]

Hi,

I received the gearwheels, now I am waiting for the motor and the controler, I hope it will come soon !

I modified the motor mount in order not to have any problem with the brake :





I will make a protective device in order the motor not to touch the ground...

[adrian_sm]

Looking good. How much work is there in modifying the wheel/axle to accept the driven gear?
The rest looks like it will just bolt on with no modifications to the scooter. Very nice.

- Adrian

[adrian_sm]

Oh, and make sure you have clearance between the screw heads and the chain, the two left most ones to mount the motor mount plate look like they are at the same diameter as the driven gear. Since you have the CAD model, best to model them up.

- Adrian

[nyx]

Nice Ferias, I can see that manage easily CAD software. I wish you to success your project as i did.

On my side i finished my scooter, i am just waiting for my 6000 mAh battery. Today i finished the hoods, its as i wanted, and i installed an 50mm fan.
This afternoon I've made tests with an GPS. on flat i can reach 20-25kph on full throttle, thats good as by pushing only with the feet (without moror) i can't go over 20kph.
On an small descent i reached 30kph, its pretty fast on a such scooter even with 200mm wheels. I definitively would not go faster...

At the end i thought i burned my motor as i did'nt avec any power but it was my ESC which was reducing the power as the Lipo was empty. I've been scared

more pictures:

https://picasaweb.google.com/thibaud.ri ... oNucleaire

[ferias77]

I just need to cut the frame for the motor mount and to drill the 4 holes. I don't need to modify the wheel. And I will use countersunk screw not to have problems with the chain.

Nice work nyx ! Do you know the weight and the range of your complete scooter?

[nyx]

Hy Ferias,

I just weighted my scooter, Decathlon annonce it a 4,7kg, mine with the brand new 3S 6000mAh nanotech wich fits perfectly in the frame weight a bit less 6kg.
I took the subway with its and i can't see the difference its really good.

Concerning the range its really hard to say as it is very variable. For going from my garage to my home, its about 1km, and i generaly pull about 600mAh using a lot the motor as the Pavements are free and I can go fast with the motor.
I've been two times in the center of the town(Lyon) with lot of people on the pavements, then i can't go fast with the motor, and i am often pushing with the foot. There i consumed about 300mAh for 2km...

well to conclue i think that at the max consumption, so in the worst conditions, the range is about 5km. But by using the motor Intelligeament, not for launching, I can easly reach 15 or 20 km.

Finally its not a lot but as the battery can just fit in the frame, and as its more than i wanted, i am really happy with it.

I think i found a way to make a freewheel with 11Tooth, I just need to find a sprocket like This 11 Tooth 10mm Bore Sprocket For #25 Chain
http://www.electricscooterparts.com/sprockets.html
But I wouldn't pay $30 of shipping just for it. Does anyone has one to sell to Me ???

Thibaud

[ferias77]

Thanks for the information about wheight and range.
How do you will make the 11 tooth freewheel? I am very interested. On electricscooterparts, it is a sproket and not a freewheel, no? I don't know where you could find it...

And I asked adrian_sm if it was necessary to add extra capacitors on the controler in order to eliminate voltage bursts. His answer, which could interest other people :

You should post this stuff in your thread. Then everyone can benefit from the answer, and I might write a more complete answer. anyway....
I haven't ever put extra caps on. But I always peddle first, and will soon have protection from people hitting the throttle at standstill.
But they can't hurt, and will help keep ripple voltages in check.
Remember my aim is to make a robust system with minimal mods to stock parts, so I will only do mods like this if REALLY required.

- Adrian

PS feel free to copy this answer into your thread if you wish.

Eric

[ferias77]

I received my motor !

So I mounted it on my scooter with the modified motor mount :





Eric

[adrian_sm]

Stop making this look so simple. You are making me want to build one.

Nice job.

- Adrian

[nyx]

Whoawo its really nice job Eric, your Support is really clean. I don't know the word for "CNC" in english, but do you have one ?
its definitively a bigger motor than meine, but i am happy with it. I am coming back from the post office, about 2km, and I used a lot the motor, lot of acceleration and nice speeds, I consume 1Ah so its pretty good, and the motor was not too hot

By mounting the motor like this, are you not affraid to shoot it with the foot when you while push the scooter with it ?

I look forward to see the next

nice job