Go Kart Rim Hub Motor

[sioux612]

Hey guys,

I'm currently in the development phase of an electric kick scooter that is supposed to use go kart wheels and tires.

I want my scooter to not have a chain or belt or anything comparable though, I want to use a hub motor.

I don't really care if it is a hub motor that is already integrated into a rim or if I have to make it fit a standard gokart rim.

It should be in the 1000-2000 rpm range, battery pack voltage is currently undecided but I might go with 36v, so a 30-60KV motor would be perfect.

The only thing I have been able to find is this:

http://www.peipeiscooter.com/default/11inch-350w-500w-wide-tire-hub-motor-phub-44

which looks super promising, until you look at the 700rpm max speed which is about 10kph.

Does anybody have experience with similar projects? I have unfortunately not been able to find anything in the forum yet.

Hope anybody can help me,

Cheers,
sioux

 

[itsid]

HI..
first.. scrap the KV idea.. that's RC denotation which IS NOT applicable in ev (electric vehicle) motors AT ALL!

frankly even in RC tech that's pure bullshirt (nothing but an indicator value)
useful only to compare to seemingly identical motors.. nothing else

Aaaanyways..
EV motors are (or should be at elast) controlled by variating the current flow, not the voltage..
so a kv rating is 100% pointless
(especially since those ratings are only w/o load... which on an EV is again.. pointless)

'sid

36V hubmotors are plentiful, 2000 rpm not since that'd mean with a average wheel size you'd go ~80mph which is NOT really an option tbh.

 

[sioux612]

I learned all I know from electric longbaords where kv is seen as an indicator of torque, I think

It's really a shame, I have yet to find a small, torquey motor in the range I'm looking.

Has nobody ever built a hubmotor Go Kart? Has everybody so far simply replaced the engine with a motor?

I'm still hoping for an answer from the PeiPei guys that tells me that I can easily overdrive their motor with no worries.

Also, does anybody have a CAD file of a 6inch rim?
If I had that and knew that it was an actual rim that I could also buy, I'd be happy to just build the motor myself

 

[itsid]

an indiator at best...
of torque that is.. could also be an indicator for the use of bad bearings

kv as you will certainly know is ONLY really telling about wiregauges strictly speaking.
In fact it's not even rpm/V...
since it's measured how much VOLTS the motor generates when turned at a specific rpm.
(interpolated average over a wide range is your kv value)
powered that value might already be different.
And since as I discussed numerous times... driving a motor by variating the voltage is almost always a bad idea if you want to propell your own butt.
Even RC controllers take the voltage from the batpack and variate the current.
(PWM)
And that's the point where an kv value is nothing but an indicator.
AAAANyways...

You can wind your own hubmotor (you can even have your own core cut by a company if you need a specific size)
and buy curved magnets in case you want a PM motor.

Sure it's been done.. not around here though.
and AFAIK not for a kart... only for kickscooters and alike.

that peipei is a 5" rim btw. and even a 6" will not have enough room to convert it to a motorized hub.
(well not without throwing lots of money at it that is)
you'd need a planetary gearbox the custom wind motor, etc.
and a way of fixing all that to one another.

sprocket chain much easier, much cheaper and not least much easier to cool
(again the motor.. since encapsulated in a rim there will be next to no airflow...)

CAD files of kart rims you'll find online...
say on grabcad
https://grabcad.com/library/go-kart-wheel-rim-tire-11x7-10-6-1
for example

That peipei is NOT an actual kart rim.
it's likely a bike hub with modified endplates and a custom rim.

'sid

 

[Dr StrangeLike]

Hello Souix,

Your project sounds interesting. Unless my math is way off, that 11 inch tire traveling at 700 rpms would be about 23 MPH or almost 37 KPH, which is pretty fast for a kick scooter, maybe a little slow for a moped. Of course it would only go that fast down a hill with a tailwind.

Mototec makes a tricycle and a scooter with a 500 Watt hub motor that is available as a part here:
http://www.urbanscootshop.com/MotoTec-500w-Hub-Motor-Wheel-p/mt-trk-500-48vmotor.htm

Golden Motor makes a motorcycle hub motor for a 16 inch tire in the 1000 - 2000 watt range. Here is an example:
http://www.ebay.com/itm/Golden-Motor-PW16D-Motorwheel-48V-2000W-/321134294778

Good luck,

Dr Strangelike

 

[sioux612]

Thank you everybody.
The PeiPei guys answered my mail as well, saying the top speed is 32kph
I must have completly messed up the calculation for the speed. No clue how that could have happened
While it certainly would be easier to buy those hub motors you linked DrStrangeLike, and probably cheaper, my goal is to build a kick scooter with Kart tires since it needs wide tires.
If it also happens to keep standing without needing a stand I'd be extra happy.

itsid, thank you for that overview of what kv actually means, I am after all still quite a noob in this regard

Given that the top speed is high enough for me, my entire plan of building the motor myself can be laid to rest.

Now the only question I have left is what Voltage I should get for the motor.
I will probably build my own battery pack, so I'm completly free in that regard.

Would one of you guys happen to know what the major difference is between a 36 and a 60 volt motor? I know that it changes the amount of current running through the motor (500/V=A) but how does it affect the motor characteristics?

 

[itsid]

ohh.. I totally missed the kick scooter part...

you can buy a bicycle hub off ebay (set with battery and controller) and with some machining and fabrication mount that to a go kart rim if you want to DIY

'sid

 

[sioux612]

I think before going with a bike hub motor that I make fit I would build my own hub motor

Given that the PeiPei motor is exactly what I need (now that I have been corrected about the top speed) I will go with their motor though.

Thank you for your help

I'm pretty sure I will come back to this forum when I decide to build a kart myself, hadn't thought about doing that in years but always wanted to

And of course I'll post about the scooter here as well, if there is interest

 

[Functional Artist]

Yea, post pics & video too.

I'd like to see this!

If I might ask:

Why a kick scooter? instead of a kart?

 

[itsid]

Why you're asking "instead" ?

Maybe it's just the smaller thing to start with... maybe it's just the vehicle he's missing.
I want an electric kickscooter myself (to commute) for example
A scrooser to be precise

Anyways... a kickscooter is usefull to some (me at times) and it takes next to no workspace to make one..
it's likely small (thus cheaper on materials)
And most of all: if you're done...it's not stopping you from stepping up into mini bikes, go karts, boats, planes...

'sid

 

[sioux612]

The scooter is not actually for me, at least not the first one I will build.
It will be used in my parents company as a means of transportation for my father. Once that one is build we might adapt the design a bit to add a way to transport stuff around.

We can't use kick scooter wheels or thinner pneu wheels though since the floor is quite slick and the company works with garbage and PET bottles in particular which are turned into PET flakes. And you really don't want to have 50% of your contact points removed by one of those flakes, hahaha

So Kart tires should be perfect.

It probably would be cheaper to buy a normal kick scooter or even an electric kick scooter. As it stands I'm currently planning on building the frame from scratch. I might buy the Battery pack from enertion, not sure yet.

And the overheating of the motor shouldnt be a problem as I can't see the scooter being used for more than a mile at a time at most

I'm currently designing a "steering rack". Traditional kick scooter steering won't work because I'm not doing a one pipe rack that I could fit into a second one, I use two pipes that run parallel to each other, both for the body and for the steering handle bars.

Most likely will just be plates with holes, affixed to the pipes, and an axle like thing running through the holes that is the pivot point.

 

[woodrowwood]

Became a member just to post a link!

This guy is from MIT I believe. He's been tinkering with hub motors for a bit!

http://www.etotheipiplusone.net/?page_id=1663