Electric Go-Kart

[Vincent]

I was wondering how difficult a project like this will be? I searched the archives and found that a few of you guys have done this. <p>Did you follow plans or did you improvise on everything? How much should I expect to spend? <p>I don't have a lot of experience in constructing things like this, but I really want to learn. I have worked with electric RC cars, so I'm guessing it will basically be the same stuff on a much larger scale.<p>Any links, plans, or advice will be great.

[gerty]

You might look at an electric golf cart for ideas.
We use them here at work, they have six 6 volt batteries for power and that may be a real consideration on a go cart for the weight and size.

[jwax]

I built one on a standard kart frame, a 1 HP 24 Volt DC Motor, Curtis solid state Controller, and 4 deep cycle 100 amphour lead acid batteries.
Chain drive with 8 teeth motor/64 teeth live axle gearing. Running the system on 48 volts, made for a helluva fun ride for 15-20 minutes, up to 40 mph on the level road.
Problems to look out for- 1.) Weight- standard frames are not made for 260 lbs of batteries, plus driver. Needs reinforcement. 2.) Safety- Imagine a crash with leaking acid and very high power DC everywhere! Even a crush of the heavy current cable to ground becomes a killer. Use disconnects! 3.) Obviously not legal on roads!
Basically a near-silent fun project! 40 mph, 2 inches off the ground, quiet speed!
All new parts- cost around $1,000.

[Vincent]

Do you have any links to suppliers?<p>The refurbished speed controllers are fairly cheap here...<p>http://www.golfcarcatalog.com/merchant. ... tep/2.html<p>Thanks again

[jwax]

http://www.curtisinst.com/ makes great controllers.

[jwax]

Imperial Electric makes Scott Motors- DC Permanent Magnet. Bear in mind that a DC motor may be "rated" at 1 HP, but is not limited to that output, since that is its continuous duty rate. In other words, Take that 12 volt, 80 amp, 1 HP motor, apply 48 volts, and stand back! Output will be many times that 1 HP rating- for awhile! Of course, the motor will run hot if it continued, but you'll only get limited time running due to battery capacity available. So, go nuts for a short while! You'll be surprised at the starting torque! BTW, England has made electric karts a sport- theres are impressive!

[Externet]

Hi.
If you want a serious, and mean serious tireburning asphaltmelting kart, I have available a 23KW DC electric motor out of an electric converted Volkswagen bug.
If you do dot want to be that much serious, can be used underpowered.
Plans? ... Bolt it on, plus belts anp pulleys and fasten your seat belt!<p>Miguel

[sofaspud]

I don't know if I'd want to steer that thing, but it makes for an awesome visual.

[jwax]

Miguel- you have my interest! e-mail specs, pics, etc, to me if you're interested in parting with it!

[Vincent]

That's a little too much for me to start out with. Hopefully jwax can do something sick with it. <p>Most of the motors are rated at a certain RPM. What should I be looking at? To go 35mph with 10" diameter tires, the axle needs to turn 590 times per minute. So, should I just look for a 2000-2500rpm motor and gear it 3:1? <p>Do you happen to have the model number of your motor and speed control so I can search for similar ones? Thanks for the help...I think I'm going to try to find a go-kart frame before buying the electronics.

[Vincent]

I'm tempted to buy this cheap thing to play around with. Is this a complete waste of money?<p>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem<p>[ April 08, 2005: Message edited by: Vincent ]</p>

[dacflyer]

this is only a 750 watt motor...i think you would need at least 1kw or more..
i forget how many watts = 1hp..

[jwax]

Well, 746 watts does equal a horsepower. Actually, for the $40 and shipping, that doesn't seem to be a bad deal! I paid Scott around $220 for a similar motor 5 years ago.
Also a good deal on controllers at that golfcart site quoted above, for a Curtis 1204, the one I had used. Again, I paid $250 for a new one.
The convenient thing about DC motors is, they are tough! You can underpower it, overpower it, change gearing every which way, it don't care!
Happy karting!

[Vincent]

Well...I bid on that motor. I'll probably end up with roughly half the power of your 1hp motor if mine is ran at 48 volts...going by V^2/R. I should have a little more run time with similar batteries and I also don't know if I want to run that cheaper motor with much more than 2x the rated input voltage. <p>I have a WTB ad on a local forum for the go-kart frame. <p>I have over 50 feet of 0 gauge from car audio installs. I'll just have to pick up a pair of 12v batteries and a recharger. What kind of batteries did you use? I was thinking about some Optima Yellow Tops, but that would be $500 to get 48 volts. What did you opt for? I'm guessing it was something more wallet-friendly since you only spent $1k total.<p>Maybe I'll just rig up some kind of on/off switch to see how the motor performs before I buy a speed control built around it. It looks like I need a core return to buy the one on the golf cart site. <p>Thanks dude...I'm excited.<p>[ April 08, 2005: Message edited by: Vincent ]<p>[ April 08, 2005: Message edited by: Vincent ]</p>

[rshayes]

Be carefull about running DC motors at higher than their rated speeds. At some point, the windings can be thrown off the armature, resulting in a real mess.<p>My impression, and this might be showing my age, is that gasoline powered go karts used something similar to a 1 or 2 horsepower lawn mower type of engine with belt drives to the wheels. Gasoline engines produce their maximum torque at close to maximum speed. The output is considerably lower at less than full speed. The gearing and clutches needed to use a gasoline engine are not very efficient, so the power delivered to the wheels may be much lower.<p>Electric motors produce their maximum torque at low speed. They won't need a clutch, and may not need a transmission. Under the circumstances, I would start with a smaller motor, or possibly two (one for each wheel) and work up to the one horsepower range in easy stages. Using two motors would avoid the need for a differential, which will also increase the efficiency.<p>There is also a limit to the power you can transmit through a belt drive with a single belt. You can use belt drives with multiple belts, but this can be tricky. I once saw what happened with a belt driven generator at the 5 KW level when one belt broke. The generator was being driven by three or four belts, but several other devices were also belt driven. Only one belt broke, but all of them came off, and for a few seconds it was raining belts (about ten of them). No real damage, since they bounced around in an engine compartment before going up in the air, but it was impressive.