diy electric go-kart

[hampee]

Me and a friend is going to build an e-kart but we need some help picking the hardware. The chassi is from an old toy gokart that we are going to reenforce it looks like this

For motors we are either gonna use this and overvolt it to around 35v http://www.robotmarketplace.com/products/0-F30-400.html or trying to get a forklift motor what speed can we expect from one of these?

For controller i am planning to build one my self with a 555timer and 10 of these http://www.sparkfun.com/products/10213
Is this a good choice?
And Is it hard to build a pwm controller if i got little to none experience?

 

[Philistine]

What is your budget, and how fast would you like it to go (ie, is it for you or kids)? I think if you answer those two questions it will help the smart guys on here help you out, otherwise there are just too many options to suggest. I presume it is for a kid or for going not that insanely fast, because I would have thought even with the frame being reinforced, there is no way those wheels could handle the lateral forces of high speed turns and burnouts you would get with a multi-KW setup, and if it is for you surely you want to strap an agni or a big golden motor to it. But if you are looking for a cheapie kid setup, different story.

 

[hampee]

We will change the wheels, the axel and heavily reinforce the chassie so that souldent be a problem(?). As far as speed goes the goal is atleast 50km/h (30mph).
The budget is low around 400$.

 

[Philistine]

I will step off at this point at let the people who know what they are talking about give some advice, but I would have thought you are going to need way more volts than that to get such speed with such a small wheel.

My suspicion is that on that budget, any motor that will get you up to that kind of speed (which might be possible with much higher voltage) will lack torque and not be much fun (kind of like a golf buggy with a high top speed), most of the electric gokarts I have seen on here (the kind that can get wheels spinning and get you peeing in your pants, use Agnis (brushed) or really substantial brushless motors, both of which run well over that budget. But I will be fascinated to hear what the learned on here have to say. The more detail you can give of what performance you want or the purpose you intend to use it for will help them help. Best of luck with it and I can't wait to see the suggestions and where you take it.

 

[hampee]

Just to make things clear.
I am an 18year old software developer at least soon i am
I would like to get a bit more experience in hardware. I thought this could be a funny litte projekt and hopfully i learn something new. But it its not all about the build we want to be able burn some rubber and have a good time driving it to.
that's probably going to be hard because of our strict budget. But if we could get a cheap forklift motor from a local scrap yard and build our own pmw controler it should be possible(?).

any help appreciated

EDIT : Any knowledge appreciated

 

[LegendLength]

This is a similar build from last year: http://endless-sphere.com/forums/viewtopic.php?f=7&t=32231 .

 

[hampee]

i'm starting to learn towards buying a cheap rc brushless motor like this one
https://www.leaderhobby.com/product.asp?ID=9394001224353

Is it a valid choice for my purpose? and is it hard to find a matching controller within my budget?

 

[TylerDurden]

A pedal frame is a death trap.

Get a used frame for <$100?

Search craigslist via google... Example:

Go kart frame for sale - $60 (El Monte)

Date: 2012-03-13, 3:47PM PDT
Reply to: dj89x-2900721672@sale.craigslist.org

I have a go kart frame for sale it use to be electric but the previous owner desided to strip it I was gonna convert it to gas but didn't have time for it I'm selling it for 60 OBO everything is still good if interested txt me at 1-six2six-274-7462

Location: El Monte
it's NOT ok to contact this poster with services or other commercial interests


http://losangeles.craigslist.org/wst/tag/2900721672.html

 

[LegendLength]

With a motor like that you'd need some sort of reduction drive which are not too easy to come by unfortunately. There are some around (for e-bikes and karts) but there are some frustrating holes in the market still.

Seeing as though you have such small wheels compared to an e-bike you can take advantage of that 'natural gearing' by matching a motor and rpm to the top speed you wish to go. For example with a 10 inch wheel you have:

0.127 m wheel radius
2 * PI * 0.254 m = 0.798 m circumference

At say 1000 rpm the speed is (1000 rpm / 60) * 0.798 m = 13.3 m/s = 47.88 km/h = 29.75 miles/h

Therefore if you wanted to have a max speed of 30 mph you'd get a motor that runs with the best efficiency at 1000 rpm. At a typical voltage of 48 V that would be 1000 rpm / 48 V = 21 rpm / V (or kV).

The motor in that link is 250 kV so you'd need a reduction unit of 10:1 to get that speed. Alternatively you could look at putting a hub motor on each wheel as they often have a kV in that good range. Controllers are relatively cheap and easy for hub motors too, and unsprung weight is not an issue here.

The only real issue I see (other than trying to mount the hub motor to the axle) is getting the two controllers to work as one. Hmm I wonder what 4 cromotors would feel like on a kart ...

 

[thepronghorn]

Ditch the ampflow motor, it's expensive and heavy for its power. The brushless outrunners that you are looking at are much cheaper for their power. Take a look at tinyKart from the link below for a relatively cheap and simple build. You already have the steering mechanism and frame, so you just need to figure out the drivetrain.

http://scolton.blogspot.com/p/cap-kart.html

 

[hampee]

Ditch the ampflow motor, it's expensive and heavy for its power. The brushless outrunners that you are looking at are much cheaper for their power. Take a look at tinyKart from the link below for a relatively cheap and simple build. You already have the steering mechanism and frame, so you just need to figure out the drivetrain.

http://scolton.blogspot.com/p/cap-kart.html

I ques an rc motor is my best bet then...
sould i get two of these https://www.leaderhobby.com/product.asp?ID=9394001224161&Location=HK
or one of these https://www.leaderhobby.com/product.asp?ID=9394001224353

In the kart on http://scolton.blogspot.com/p/cap-kart.html they use verry small controller is it relly enough?
http://kellycontroller.com/kbs24051e30a12-24v-mini-brushless-dc-controller-p-817.html

EDIT: someone know a cheap place to buy hall effect sensors?

 

[Dauntless]

I ques an rc motor is my best bet then...
sould i get two of these https://www.leaderhobby.com/product.asp?ID=9394001224161&Location=HK
or one of these https://www.leaderhobby.com/product.asp?ID=9394001224353

In the kart on http://scolton.blogspot.com/p/cap-kart.html they use verry small controller is it relly enough?
http://kellycontroller.com/kbs24051e30a12-24v-mini-brushless-dc-controller-p-817.html

OUCH! The controller they have is NOT the one you posted, it's this one. http://kellycontroller.com/kbs3610140a24-36v-mini-brushless-dc-controller-p-502.html
Considerably more substantial. Not having worked with this yet, but planning to, let me say NO, that is still NOT big enough, at least if you get the motor they have, the larger of the two you posted. Just because it hasn't blown up YET doesn't mean it's not going to. Let me offer a bit of influence in the direction of http://kellycontroller.com/ksl4815024v-48v150asensorless-bldc-controller-p-661.html If you don't want to spend that, you can save $50 (At first) with http://kellycontroller.com/ksl4810024v-48v100asensorless-bldc-controller-p-660.html

People with slightly larger RC motors have expressed their pleasure with http://www.rcdude.com/servlet/the-1614/Castle-Creations-Phoenix-ICE2/Detail Yours being a big smaller if you get that 6kw motor, you might risk saving the $50 and going with http://www.rcdude.com/servlet/the-1815/Castle-Creations-Phoenix-ICE2/Detail

Well, that's funny about those motors you posted, though. My backordered motors from HobbyKing, matching those numbers, look just the same too. Say, you don't suppose one is a knockoff of the other, do you?

At least if you order from your source, you might see yours sometime soon. I'm just sitting here watching the grass grow as I wait for the mailman. . . .

 

[The Mighty Volt]

My advice would be to avoid that frame and pick up a cheap go-kart frame off ebay or the like- much stronger and much more reliable.

 

[hampee]

I have actually found a sponsor that will make a frame for free including the material. All i need to do is send them my design

 

[Hillhater]

I have actually found a sponsor that will make a frame for free including the material. All i need to do is send them my design

A waste of time and money when there are so many properly designed & well engineered kart frames around for low dollars.
Use the sponsor money where you will need it most ,..controller, battery , drive components.

 

[strantor]

This is a similar build from last year: http://endless-sphere.com/forums/viewtopic.php?f=7&t=32231 .

That go cart frame just went to the scrap yard along with 1200lbs of other misc crap I had laying around.

If I could make one suggestion, start with a decent frame. That's one of the reasons I scrapped my project. Even my frame (about 10X beefier than your toy kettlecar frame) required so much work to fit a normal sized human that it would have been easier to build one from the ground up. You won't be able to weld to that kettlecar as the tubes are probably like 30guage coat hanger metal, and if you try to drill through & bolt to it, it's just going to fold in half from compromised scructural integrity.