Twin motor question

[Dr StrangeLike]

Thanks for welcoming me to the forum. I think I am ready to ask my first question. I have been reading and researching with thoughts of building an electric kart for my kids (ages 9 and 11). My first question is about twin motor electric karts. I am considering building a kart with two 750 watt motors and separate rear axles. I have read a few mentions that this can cause problems, but not a lot of specifics about those problems. I am assuming that one of the problems (besides just being overly complicated) would be a sort of torque steer issue that could happen if the two motors are pushing unevenly. I know this is not the classic example of torque steer that exists in some cars where the counter-rotation of the engine tries to push the car to one side, but I am using that terminology because I don’t know what else to call it. In this case (two motors), I am assuming if one motor pushes harder than the other, it will try to steer the cart in the opposite direction. Do you think the steering issues would be worse than the steering issues (tires scrubbing on turns) that happen with a live axle setup (one engine) on pavement? Would the two motors balance themselves to some degree based on the work being demanded of them? I have seen a couple of examples where this was done:

http://buggies.builtforfun.co.uk/Racer/index.html
http://www.instructables.com/id/Electric-Microkart-with-Independent-Suspension/
http://www.instructables.com/id/Chibikart-Rapid-Prototyping-a-Subminiature-Electr/

I know these are some very odd examples, but I am OK with odd sometimes. I have other questions as well – one controller or two? (I am guessing two identical would be better), one big battery pack or two separate packs? (I am guessing one would be fine), and would a single throttle send a satisfactory signal to two controllers at once? (I may just have to experiment and see). Feel free to ignore these extra questions for now if you like. And feel free to abuse my ignorance. I taught physics, but I know amazingly little about real world engineering issues. Thanks in advance for your wisdom.

---------- Post added at 03:29 PM ---------- Previous post was at 03:26 PM ----------

I noticed that my hyperlinks did not show up in my orginal post, so I will try it again.

Examples of twin motor electric karts:

http://buggies.builtforfun.co.uk/Racer/index.html
http://www.instructables.com/id/Electric-Microkart-with-Independent-Suspension/
http://www.instructables.com/id/Chibikart-Rapid-Prototyping-a-Subminiature-Electr/

 

[dcastillo]

Im no expert, and I also am considering a dual motor setup, once time and funding allows so I look forward to your build and updates...

As for steering issues, I dont think you will have any. My daughters electric cart is driven by a single rear wheel and has no problems with pulling to a side. if one motor is slightly faster then the other, the slower one (depending on how you setup up your controller (single or dual, series or parallel) will receive no power and the cart will drive like a single wheel cart until you hit turns or offroad resistance I would imagine.
were you thinking one controller or two?
Please keep us up to date as I am very interested in the outcome (due to low funding and time, I need to get it right the first try)
-Danny

 

[Jrgunn5150]

The only issue I see with using twin motor's, is you'll need two controllers, or one expensive one probably.

Also, if they aren't matched correctly, one will drag on the other and eat efficiency up.

As for steering push, I don't think that would be an issue, not to any degree enough to matter.

For what it's worth, modern electric trains (full sized) use a motor at each wheel.

 

[bob58o]

If engines burn fuel and motors run on electricity, why do cars and go karts have motor mounts?
And why do you park in a driveway and drive on a parkway????

 

[Poboy kartman]

Why is Bob a motor mouth?

These are the mysteries of the universe....

 

[chancer]

And why do you park in a driveway and drive on a parkway????

Your Drive way is actually the "Drive" to your Garage, where you should park!
Parkway... Ever see the old photos of Main street USA where cars pull in to park rather than paralell park? That is a "Parkway"

Got any more questions? Bro

 

[Poboy kartman]

Actually...to get to GoPowersports....I take I-35 to Tarrant Parkway....and parking on it...not recommended!

 

[chancer]

It was more of a word origen thing.
Or For Hellion "Etymology".

 

[Iron John]

It was more of a word origen thing.
Or For Hellion "Etymology".

Maybe he had ants in his pants. AKA Entomology.