Nir's ekart

[baer]

Hi I am Nir, I live in Israel and I am just starting now building an e-kart for a 4 years old.
I am thinking of using 2x 1m long metal rectangular 30x30mm rods.
motor is 24v/350W.
I already have a rear axle (25mm dia), bearings and wheels.
Steering spindles will be custom built like the ones in northern-tools
and following Ron Champions book steering angles (i.e. caster of 15 degrees and camber of 10 degrees).
I will be happy to hear suggestions especially for the steering which is not started yet.

 

[Ghanem]

Man I have 36 v motorhttp://www.diygokarts.com/vb/showthread.php?t=10959&highlight=electric+project

 

[Doc Sprocket]

and following Ron Champions book steering angles (i.e. caster of 15 degrees and camber of 10 degrees).

Hi, Nir- welcome to the forum! I have studied Ron Champion's book at length, "Build Your Own Off Road Buggy", and have found a few errors and omissions. Nothing too serious, but one of them does pertain to the steering geometry. His geometry is good, but the refers to a camber angle that does not exist. When you build according to his plan, you end up with a 10* KPI angle and zero camber. This is fine, but the text will confuse you.

I am more than happy to go over any of this with you that you like, and can use page numbers and paragraphs to reference things in the book.

If you like, start a build thread in the "Photo Gallery and Projects section of the forum. Cheers!

 

[baer]

Thanks for the welcome.
Since I have no experience with steering angles (and didn't start welding or even collecting all the steering components) I will like to hear from those who are experienced.
As I read, the camber angles loads the inner wheel in curves and makes it easier to turn and the castor help centering the steering.
Also in the book, the |_| shaped piece is actually rotating left-right with the wheel and I tend to prefer the northen-tool solution as the size of my ekart is much smaller.

 

[Doc Sprocket]

The bracket you refer to can either be part of the spindle assembly or mounted to the frame. Whatever works for you.

 

[baer]

Some progress was done, I welded a simple frame and connected the rear axle and a motor mount.
Problems: the sprocket on the shaft is not aligned and also not centered to the shaft accurately enough - the motor does turn the wheels but not smooth as I want too.
Controller - The one I had (YK48-2 from TNC) turned the motor for exactly 10 seconds before giving up, I did some "reverse engineering" and built a similar one with new components I ordered (I used only the original relays, wiring and case).
The new mosfet (link) seems to do the job, I still have to test them more seriously.
pics soon.

 

[baer]

As you can see, I had to figure a sprocket adapter plate to the shaft.
I am not happy with the welds and they are definitely going to improve.
A short video of the controller working:
http://www.youtube.com/watch?v=pshvk9zkqzM

 

[Ghanem]

nice

 

[gokart14]

i woulden t have welded the sproket to the shaft

 

[baer]

i woulden t have welded the sproket to the shaft

I also didn't want to but eventually I did since I want to keep simplicity and budget, using a sprocket flange would cause the need for wheel hubs and a whole different wheels...
The idea behind this kart is also to be a preparation for a larger one with fuel engine that will come at later stage.

 

[oscaryu1]

You built the controller yourself?

 

[baer]

Yes, I used the existing setup for the power components and pwm generator from 4093 schmidt trigger.
See attached.

 

[baer]

Weekend progress - figured the steering.
caster - 15°, camber - 10°, ackermann - 14°
Tie rod bearings arrived and I am thinking what is the minimum size of tie rod I should take - this part stress is only on it's axis so I guess it doesn't have to be too thick. I found a round bar 14mm dia. and 0.8mm wall thickness - would it be o.k.?

 

[baer]

Done the steering. The tie rods were supposed to be adjustable but eventually welded them to a fixed length, due to welding simplicity.
Looking for a custom steering wheel, I have an idea to take 12" bicycle rim and continue from there. any suggestions?

 

[baer]

Steering column holder.
I tried to make it so taking out the steering column will be easy (4 screws) since the steering wheel is not available yet (surprise on that one...).

 

[anderkart]

Looking good man

Only suggestion I've got is you should consider slightly re-locating your steering column so your tie rods end up perfectly level/straight-across while the steering is centered.

 

[oscaryu1]

Did you use the original IC with that controller?! :O

I'm kinda needing help re-building my controller for higher amperage draw... I Was wondering if you could help me with that? :happysad:

 

[baer]

I didn't use ic, see the above schematics.
In general, to handle extra power you only have to use larger transistors and heat sink.
But if your controller is working well I wouldn't touch it.

 

[oscaryu1]

Erm. I'm an electronics amateur... a PIC then?

It "works" fine but I need more amperage out of it :\ I'm ordering higher voltage and amperage mosfets for it... but I'm worried the FET drivers can't drive them.

If I may ask, where did you learn about electronics? I'm trying to start with just modifying my controller but even that is too much to ask ):

 

[Hunterk97]

As you can see, I had to figure a sprocket adapter plate to the shaft.
I am not happy with the welds and they are definitely going to improve.
A short video of the controller working:
http://www.youtube.com/watch?v=pshvk9zkqzM

What is the rpm of that motor and where did you get it and for how much?