Making electric gokart

Discussion in 'The Projects Forum' started by TheFauxFox, Aug 20, 2013.

  1. TheFauxFox

    Thread Starter New Member

    Aug 20, 2013
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    Hi guys. So...

    I plan on making an electric gokart soon (300w 4wd [4 motors] 24v) and was wondering what to do about batteries?

    I was thinking I should find about 4 9ah 12v batteries, and take 2 and wire them in parallel, and then do the same with the other two, and then connect the two packs in series.

    Does that work?

    I'm trying to get 18+ ah while retaining 24v and NOT purchasing ginormous batteries (lol).

    I would think this works because I would essentially be creating a 2S4P "pack" correct?


    Thanks guys! I'm quite a newbie in this topic, but I would love to broaden my knowledge of it!

    Thanks again
     
  2. strantor

    AAC Fanatic!

    Oct 3, 2010
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    If my "pack" terminology is not wrong, I believe that would be a 2S2P pack. Other than that, sounds good. You do realize this is going to a a very wimpy go-cart, right? Like a child's Fisher Price Power Wheels car probably has more balls. 300W is less power than a kitchen blender.

    [​IMG]

    I had a gas powered go cart like the one shown below as a kid. It had a 5HP ( 3,730W) motor on it and would go 15-20mph (about as fast as you can ride a bike), and would do a little 2 second single tire burn-out as long as I was on gravel. That awesome performance was when I weighed maybe 75lbs. Now that I weigh 200lbs I doubt it would even move if I sat on it.

    [​IMG]
     
    Last edited: Aug 20, 2013
  3. LDC3

    Active Member

    Apr 27, 2013
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    That's quite ambitious. Will you be giving these a run for the money?
     
  4. TheFauxFox

    Thread Starter New Member

    Aug 20, 2013
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    300w is plenty. It's a 4WD so it will have 1200w of total available power... If my research proves right, the more motors you have, the more torque you have (assuming they are all geared somewhat high) so...if I end up gearing my motors low, the "lack of" speed goes away due to my gearing, and torque should be decent....go on youtube and type in "300w 4WD gokart" you will find what my inspiration is...I might upgrade to a bigger motor, we shall see... Anyways this is just in the planning phase and I wanted to know about the batteries.

    I'm not sure where you go 2S2P from?

    4 total batts split into 2 groups. Each group (of 2 batteries) is wired in Parallel to "boost" AH. Then, the + and - leads coming off of the new "packs" I made will be wired in series so that I get 24v...
     
  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    For 19AH driving a 300W load you get a run time of about 20 minutes... longer if you don't mind frequent battery replacements.
     
  6. Shagas

    Active Member

    May 13, 2013
    802
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    Why don't you look into LIPOs?
    They are lightweight and provide huge currents although You will spend more monies on them + a good charger + protection circuitry
     
  7. strantor

    AAC Fanatic!

    Oct 3, 2010
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    2S2P means "two cells in series, two series strings parallel" for a total of four. 2S4P you are suggesting would mean "two cells in series, four series strings in parallel" for a total of 8 cells. More info here.

    I watched the videos (part 1& 2), and that is a pretty impressive project. That is a hybrid go-cart and it is using the gas engine to keep the low-capacity batteries charged. You made no mention of a gas engine, so I assume you're planning to go pure electric? If so, this is doomed. Take what ErnieM said, and multiply it by disaster. He was assuming one 300W motor, not four. The run time will not be 1/4 of what he said, it will be worse than that since AH figures decay exponentially due to peukert effect. you will be drawing at least 100A on take-off. You need to look into lipo batteries. Check out the hard case turnigy packs at hobbyking.com; they have low AWG leads to accommodate the high amp draw.
     
  8. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Strantor,
    The OP said he would be using 4 x 9ah 12v batteries.. Not as bad as you said but still, no kid wants to ride for 10 minutes and wait 2 hours for a charge.

    Nothing makes a kid feel great like an internal combustion engine!

    When my son was 12, we mounted a weed whacked motor on a bicycle. He was thrilled and could ride all afternoon on a mini tank of gas. When he ran empty, he filled up in 2 minutes and he was riding at full power.
     
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