A light electric stand up scooter

[adrian_sm]

First up. That is an awesome build. It is so compact, I love it. But I don't think that motor will last. Even with a little fan attached to it, it will struggle. You will need to either go for a bigger motor, or limit the current going to it, which will also obviously limit the power you can get from it.

Here is a link to a mod I did to a watt meter, that allows you to have it mounted up on you handlebars, without running the battery wires the whole way. Hope it helps.
viewtopic.php?f=28&t=22187&start=270#p350307

I have also modified the watt meter to actually act as a servo tester, and limit the throttle when the current gets to high. It works fine without the remote shunt mod above, but never worked with the remote shunt due to electrical noise issues.

Here is a link to Jonas' mods that I based it on:
viewtopic.php?f=28&t=22187&start=165#p337690

Hope that helps.

- Adrian

[nyx]

Thanks for the links Adrians,
I don't know if i'll make a such mod, i think i will place the wattmeter at the half height of the handlebar, by this way once the scooter Folded the wattmeter will be more protected. I am stell thinking about it.

Yesterday i made new tests with my 3s 2200Battery. Even with this low capacity the power was really good, in fact as good as the 4s 5000, that because i didn't use full power on the 4S.
so its decided, i will use an 3S 6000mAh, as you said Adrian, i will have less power than with an 4s battery, but with an 3s i am allready at the max capacity of the motor, so more power from the battery should only by usefull for burning the motor
then i made an test in real condition : going from my garage to my home, its about 1Km. 4 road to cross. At each acceleration, i helped the motor with the foot. Finally it perfectly fits with what i needed : an light electric scooter with a small motor just enough to maintain the speed.
the speed was good, on flat i think i am about 20-25Kph. and finally the motor was not hot. on flat at constant speed it pulls between 100 and 200Watts.

now i have to pass all the wire in the scooter, make Hoods for protecting the battery, the motor and the chain. And Finally make an system to Tighten the chain.
i'll make new pictures.

and then, i'll can go to work with my scooter by taking the subway

[swbluto]

First up. That is an awesome build. It is so compact, I love it. But I don't think that motor will last. Even with a little fan attached to it, it will struggle. You will need to either go for a bigger motor, or limit the current going to it, which will also obviously limit the power you can get from it.

I regularly run the same motor at 25 mph and I climb hills with it, and it's not burning up anytime soon. The hottest it gets is to 150 degrees which is far away from its temperature limit (Which is something like 300-400 degrees).

[adrian_sm]

Here is the motor i selected :
http://www.hobbyking.com/hobbyking/stor ... duct=14740
It as a 450KV and can reach 1000W

I regularly run the same motor at 25 mph and I climb hills with it, and it's not burning up anytime soon. The hottest it gets is to 150 degrees which is far away from its temperature limit (Which is something like 300-400 degrees).

Really you use that little guy at 25mph, and hills. No current limits?
I assume those temps are in farenheit.

[nyx]

Adrian, i Think it is possible with an big reduction and 5 or 6S batteries the motor can reach 1000W without pulling more than 50A which is his max. On my side i will check the Timing of my ESC because i am not sure of it.

To complete yesterday i pulled about 450mAh for 1Km then with the 6000mAh battery, i should reach 10Km which is more than hopped.
Question to expert : My #25 chain is too long, do you think that i can cut one link and continue tu use the master link?

Thibaud

[swbluto]

Here is the motor i selected :
http://www.hobbyking.com/hobbyking/stor ... duct=14740
It as a 450KV and can reach 1000W

I regularly run the same motor at 25 mph and I climb hills with it, and it's not burning up anytime soon. The hottest it gets is to 150 degrees which is far away from its temperature limit (Which is something like 300-400 degrees).

Really you use that little guy at 25mph, and hills. No current limits?
I assume those temps are in farenheit.

LOL. Ok, I admit I was looking at the original post where he talked about the 3250 W 63-74 Outrunner. Yeah, that little guy might have heating problems with continuous power requirements above 500W or so (Like climbing a long 7% hill), though I wouldn't doubt it could easily sustain 15 mph on flat land.

[nyx]

LOL, i read 25 Kph, but 25mph effectivily would be incredible for this motor

[ferias77]

Looking at all the motors available to Hobbyking, I found this :
http://www.hobbyking.com/hobbyking/stor ... oduct=4651
2 times lighter than the 63-74 170 with a Kv of only 206 ! But 43 A max... I don't know if it would fit.

I regularly run the same motor at 25 mph and I climb hills with it, and it's not burning up anytime soon. The hottest it gets is to 150 degrees which is far away from its temperature limit (Which is something like 300-400 degrees).

swbluto, with what vehicle and what voltage do you use de 63-74 motor? Is it the 170 Kv? Do you use a freewheel? I think I won't use any freewheel for the first design, but I would like to be sure not to burn the ESC when the motor is not running...

Eric

[nyx]

Hi Eric,
I saw this motor too, its looks not bad, but a bit too long for my scooter. I think 43A is not a problem if you have a big reduction and enough Volts.
Concerning the ESC if you use airplane/heli ESC you won't have problem as it is designed for it. I often saw planes flying with me motor cuted but with the Helix turning because of the wind, do you see what i mean?

The only reason i took a freewheel is to use the scooter without the motor slowing down me. But i would prefer an 10tooth freewheel, if anyone knows if it exsist, I take !

[swbluto]

Looking at all the motors available to Hobbyking, I found this :
http://www.hobbyking.com/hobbyking/stor ... oduct=4651
2 times lighter than the 63-74 170 with a Kv of only 206 ! But 43 A max... I don't know if it would fit.

I regularly run the same motor at 25 mph and I climb hills with it, and it's not burning up anytime soon. The hottest it gets is to 150 degrees which is far away from its temperature limit (Which is something like 300-400 degrees).

swbluto, with what vehicle and what voltage do you use de 63-74 motor? Is it the 170 Kv? Do you use a freewheel? I think I won't use any freewheel for the first design, but I would like to be sure not to burn the ESC when the motor is not running...

Eric

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.

[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 1114 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.