Please read. electric go-kart questions

Discussion in 'The Projects Forum' started by tyrone7474, May 21, 2012.

  1. tyrone7474

    Thread Starter New Member

    May 21, 2012
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    Hi everyone. i am 17 and i am thinking about makeing a electric go-kart

    i need to know if one or 2 things would work...

    i am thinking of useing a car starter motor.. would that work?:confused::confused: and also im thinking of useing 2 car batterys. 12v i think they are. not to sure at this point.

    so it should be 24v..

    i am also thinking about if a car altornator would charge up the batters :confused::confused: if anyone could awnser these questions asap as i might start it today and go out and get the parts...

    also.... just wondering if 2 washing machine motors on the back wheels would make it move?? im not sure if they would push the kart.. ??? anyone know.. :confused:


    Thanks for takeing your time to read this.. sorry about the spelling..
     
  2. strantor

    AAC Fanatic!

    Oct 3, 2010
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    starter motor would probably work, but assuming you're using the starter solenoid to run the starter, you're not going to have any speed control, just off/on. It also probably won't work for very long, as starter motors are rated for intermittent duty; if you run it continuously, it's probably going to overheat and die.

    I've only ever seen one washer motor and it was a series wound universal motor. That *could* theoretically work with DC from car batteries, but it's designed to operate around 120V, not 12V so probably going to be slow.

    A car alternator will work; that's how batteries are charged in your car. However, if you're planning to try to charge the batteries while driving, that's overunity and won't work. To use the alternator, you need to pass current through the field winding; i've never done this, so I don't know how much current - maybe you just connect 12V to it or maybe you need a resistor, someone here should know.
     
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  3. tyrone7474

    Thread Starter New Member

    May 21, 2012
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    hmmm.... thanks for the info ;) do you recomend ANY sort of motor for one... as i dont want to use a engine. i want it to be electric ;D i have 2 car batterys so thats about 24v.... i was also thinking...

    WOULD a truck starter motor work??? :D cos they are more dureable.. also.. i could try set up something like a cooler so it dont over heat??:confused:
     
  4. jwilk13

    Member

    Jun 15, 2011
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    I've never built an electric cart before, but I would guess that you might want to look into using different batteries in the future as well. The car batteries should work for a while, but they're not meant to be fully discharged. My recommendation would be some sort of deep cycle battery like a marine battery or something from an electric scissor or boom lift.

    As far as the motors, I would agree with strantor.
     
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  5. MrChips

    Moderator

    Oct 2, 2009
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    Starter motors are easy to come by. Why not try it with one 12V battery?
    Two batteries will burn out the motor.
     
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  6. wayneh

    Expert

    Sep 9, 2010
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    You could learn a lot about your project challenges by reverse engineering an electric golf cart or even an electric wheelchair. With enough Googling, you can probably find parts diagrams and such. You might even be able to find an old junk golf cart cheap, that you could rip apart.
     
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  7. n1ist

    Active Member

    Mar 8, 2009
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  8. tyrone7474

    Thread Starter New Member

    May 21, 2012
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    how quick will it go with just one?
     
  9. wayneh

    Expert

    Sep 9, 2010
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    That's impossible to predict. It depends on motor power, drag, gear ratio and so forth. Fast down a hill, uphill not so much!

    FWIW, I think a regular go-cart can be pretty darn speedy with a 3HP gas motor. A large-ish DC motor you can find easily might be only 1/2HP, so it simply won't be as fast.
     
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  10. Markd77

    Senior Member

    Sep 7, 2009
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  11. tyrone7474

    Thread Starter New Member

    May 21, 2012
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    Okay so right... if i put a starter motor on say a 70ish to 90ish,kg kart. with One 12v battery.. yes i know its going to be one speed on and off.. but say if i just put the one 12v battery on it would i hit about 20-40mph?...

    and also... to stop it from over heating could i like make a little circuit going to the battery to turn it on and off like a little flick switch...??

    AND now this might sound stuped! but...

    you know in your house on your walls... you have a light switch on your wall. well i was thinking of getting one like this. http://tiny.cc/b09new that is a shortend url to a photo the normal link was to big... but could i use the switch to turn on the motor and the knob to speed up or slow down????....

    i think its a good idea ;) just need to know if it will work...


    Thank you people for takeing your time to help me

    once again sorry about the spellling
     
  12. tyrone7474

    Thread Starter New Member

    May 21, 2012
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    cos i was thinking because it turns down the voltage on a light to make it dim so it uses less power. and if you turn it up so it pushes out more power....??? sorryaboutallthequestions

    the photo is the link above just incase you dident want to click it

    :D:D:D:D
     
  13. strantor

    AAC Fanatic!

    Oct 3, 2010
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    No way man. you cannot use a household light dimmer switch to control the speed of a automobile starter. The device needed to control the speed of a motor is called a drive, and with the amps that a starter pulls, the drive that you would need, would be hundreds of dollars. You cannont even use a light on/off switch to cut battery power; those are only rated 20A max I believe. You could probably use one to switch the solenoid, but even that is maybe cutting it close.
    I doubt very seriously that you are going to get anywhere near 40mph. watch this video. That guy is using the biggest, baddest starter I've seen, a 24V (18 wheeler) starter and my estimate is he only gets up to 30mph.
    I've looked into all this before. I started an electric go cart project (never finished it) and originally I planned on using a starter motor for it. What I found through much reading is that it's really not a good idea. I ended up buying an expensive motor which I still have not used. Check out my build thread, there are lots of links which might help you.
     
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  14. wayneh

    Expert

    Sep 9, 2010
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    +1 Not even close, for both the dimmer or the switch, unless the latter is used only to activate the starter's solenoid.

    OP, do you have a drivetrain plan worked out? You'll need a way for your cart to come to speed while the motor works at its "full" speed. My buddy's go-cart had a centrifugal clutch and a drive chain. The ratio from the engine to the wheels was maybe 8:1.
     
  15. alacrity

    New Member

    May 21, 2012
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    What you want is an Agni motor and a bunch of lithium ion batts (as used in power tools) made into a rechargeable package.

    Then you better do some serious work on your frame,steering and braking systems, because this will put the GO in go-kart. :)
     
  16. strantor

    AAC Fanatic!

    Oct 3, 2010
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    shiiiiittt... I don't think a guy who's dream is to control a second hand starter motor with a dimmer switch is going to be too excited about paying for all of that. Money is the reason I never finished my own project. I payed 400$ the motor, which is about half as bad-ass and 1/3 the price of an agni, and then couldn't scrape up enough for LiPo. You're probably talking 2500$, assuming he's already got a frame that will handle it.
     
  17. tyrone7474

    Thread Starter New Member

    May 21, 2012
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    i have 3000gbp but i only want to use about 1500... i live right next to a scrap yard aswell what has scrap trucks ad cars so i can get most parts cheep.. im thinking about useing my 2, 4hp lawnmower engines as i have in my yard..

    i know i said i wanted electric.. that is because i love the Torque the things give out as soo as there connected :)

    BUTim going to try out my lawnmower engines :) should be pritty quick as my mate has the same engines on his he only has one though



    Thanks everyone 4 you guys helping!

    please keeeep posting. :)
     
  18. cork_ie

    Member

    Oct 8, 2011
    348
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    Depending on what you want to do I would suggest that you start off with 2 12V wiper motors.
    Try and get them from something with a large windscreen, so you will have the strongest motors possible.While you won't be winning any races with them they are cheap and easy to get. They already have significant gear reduction and will give you good torque without paying out a lot of money. The current consumption will be relatively low compared to a starter and hence the battery will last a lot longer.
    Finally, at the type of current they consume you will be able to build a cheap PWM speed control based on a 555 timer and a few Mosfets such as IRF540N's.There are loads of circuits here in the projects forumn on how to do this.
    Good Luck
     
  19. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    A wiper motor does have a lot of torque but no speed. Most are only <45RPM out put. To get any speed you would need to gear it up between the motor and wheel, and that would just lower the amount of torque. Torque is what makes something move - horsepower makes it fast.
     
  20. cork_ie

    Member

    Oct 8, 2011
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    He could still get an easy 10 MPH with 1ft Diameter wheels using just bicycle sprockets with 3:1 ratio. The lad is 17 with very limited skills (judging by his original proposal) and unlikely to be doing anything too high tech. Anything above 10 MPH , Ackerman angle, camber and castor angles are all going to come into play and it is going to require some serious money for brakes , steering chassis etc. at that stage. I don't think he is talking about a competition Go Cart , I think this is just a toy for a bit of fun. OP may correct me if I am wrong but that is the impression I get.
     
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