# Building an Electric GoKart--Motor Help



## JonathanEngr (Mar 28, 2020)

Hi, all. I would like to build an electric gokart for my son. He has special needs, and as a result he has limited ability to do many things. However, one thing he can do and *loves* to do is ride vehicles. 

Years ago we purchased a "drifter" electric cart that he loved, and has since grown out of. We have a kawasaki mule that he enjoys driving, but it's a bit less thrilling and isn't the quietest thing around. We have wonderful neighbors, but I would really like to have something that I know isn't bothersome to anyone.

So...I'm pretty handy (not good, but handy!) with a welder, and building the gokart frame and all associated parts (steering, brakes, axle, etc., etc) isn't a problem. However, I just don't know enough about electric motors and controllers to feel confident in what I'm doing.

There are places online that sell kits that include the motor, controller, etc., even with a gas pedal and batteries for a price--is this the best way to go? I priced a kit the other day that was roughly $400 for a 36v, 1000-watt motor and controller, pedal and three, 12v 17ah batteries. I think I would definitely want to up the battery capacity, but is this setup enough?

I don't want to go crazy--I don't need a 40 mph kart or anything--but I would like it to be spry and fun. Right now he weighs about 100 pounds, and assume another 100 pounds for the frame/motor/batteries (maybe?). Also consider I might hop on it sometimes, and I'm about 195. So... a max weight of 300--maybe 350 with bigger batteries? We do have some hills in the neighborhood, but nothing over 8%-10% grade for short lengths. (As far as weight, I'm planning this to be a one-seater... so only one of us at a time).

Would the 1000 watt motor be enough? Should I look for a repurposed motor like a forklift or golf cart motor? Etc., etc. And, of course, I'm trying to keep this project as reasonably priced as possible. 

I'll stop here before this gets too long to read (it may be there already!). Any advice/input would be greatly appreciated, and please feel free to ask questions about any further info you may need.


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## Immo1282 (Jul 12, 2019)

The motor kit you described - do you have a link for it? It will likely be a little under powered - especially if the seller is being _generous_ with the ratings...

From what I saw when I was keen to try and build an ebike - these kind of kits are set up for Ebikes, often with a hub motor on a spoked bicycle wheel, which may not suit your build well (think about offroading on a 350lb kart with flimsy bike wheels - it's not going to last well).

Good luck with the project though  Hope your son ends up enjoying the final product!


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## JonathanEngr (Mar 28, 2020)

Immo1282--thanks! I actually spoke with someone from their company on the phone, and he was the nicest, helpful guy. He even recommended the 2000w package they have, and also offered up that gokart motors would be more powerful than even their 2000w motor. I think what appealed to me is how simple the setup would be. He told me that their motor guy actually color codes all of the cables making hookup much easier--a plus for me. I'm no stranger to electricity and wiring, and I'm a computer geek at heart. However, I have almost zero experience with DC motors and controllers, and I want this setup to be reliable.

Here's the link to the 1000w, 36v kit for $313.50 (with three 15Ah batteries):
https://cart.electricscooterparts.com/36-volt-1000-watt-electric-go-kart-kit-with-reverse-KIT-153

Here's the link to the 2000w, 60v kit for $365.09 (no batteries):
https://cart.electricscooterparts.com/60-volt-2000-watt-electric-go-kart-power-kit-7600

The 2000w kit doesn't come with batteries, so that cost would have to be added. I'd be looking at another $400 for five 35Ah batteries. With shipping that would be around $900 or so. Is my math correct that it would be around a one-hour run time with those batteries? (2000w/60v = 33 amps).

I can find a used golf cart motor, but I wouldn't have any idea if it's in good shape. I understand you have to fabricate a shaft, etc., for them? I've also seen many people talk about forklift motors. Again--no idea how to evaluate them, and what about controllers? From the few Google searches I've done it seems some feel you need a controller amp capacity 2x, 5x, and even 10x the anticipated current draw. Ugh... just seems like so many places to go wrong.


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## Immo1282 (Jul 12, 2019)

Frankly the 2kW kit looks pretty decent for the money. If others on here have other suggestions I'd listen well though...

Lead-acid (or AGM) batteries are fine if you can get them cheap - but really not the best. Lithium batteries while needing a little more thought when it comes round to charging are more energy dense, volumetrically and for a unit weight - so I'd try to use them if you can find ones at a comparable price. 

For those who are converting actual cars, lithium batteries are pretty much a necessity due to the power demands of large motors - but you shouldn't run into this issue as your use-case doesn't care about a 50+ mile range at highway speeds 

Bear in mind that you're unlikely to be drawing a constant steady current of the maximum motor load, so your calculation for runtime is over-simplified. Additionally you may need to factor in temperature, battery wear and other factors (especially important if you're planning on using Lead Acid batteries)

Forklifts normally use series-wound (brushed) DC motors - your kit uses a brushless DC motor. A forklift motor will be a lot more involved to set up and use, you'll need to match a controller to it and do a lot more reading. Other thing with a forklift motor is that the power output is probably closer to 50-100x what you've looked at so far. People have used forklift series-wound DC motors on here for highway-capable full weight car conversions to great effect. Will mean more fabrication required too, as you correctly stated you'll need to figure out shaft adaptors, gearing etc.


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## lawrencerhodes (Mar 31, 2008)

Also consider I might hop on it sometimes, and I'm about 195. So... a max weight of 300--maybe 350 with bigger batteries? We do have some hills in the neighborhood, but nothing over 8%-10% grade for short lengths. (As far as weight, I'm planning this to be a one-seater... so only one of us at a time).

Would the 1000 watt motor be enough? Should I look for a repurposed motor like a forklift or golf cart motor? Etc., etc. And, of course, I'm trying to keep this project as reasonably priced as possible. 

I'll stop here before this gets too long to read (it may be there already!). Any advice/input would be greatly appreciated, and please feel free to ask questions about any further info you may need.[/QUOTE]

I think Lunacycle Cyclone parts are the best bang for the buck. However if you do two lower power hub motors laced to 20 inch or smaller wheels you will have strong wheels and adding a suspension will will help make the vehicle controllable. https://lunacycle.com/motors/


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## remy_martian (Feb 4, 2019)

You didn't say how fast you want to go up that hill. That's what the power of the motor will give you. 

You could use the 1000W motor to lug around all that weight, or you could get him & yourself a Barbie Jeep for likely the same performance.


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## jwax (Oct 1, 2018)

New here, but here's some history: Some 20 years ago I took a stock gokart frame, added a "1 Horsepower", 24 volt DC motor, a Curtis controller, and 2 lead acid 12v, 30 AHr batteries. Performance was pitiful. (BTW, 1 HP is 746 watts)
I upped the batteries to 4 12v, 80Ahr batteries, and ran the beast at 48 volts. The controller allowed that voltage, and I had a screamer! Snappy acceleration, and a top speed of 40 MPH. 
But, it was heavy for those batteries and my 200 lbs. By the time (15-20 minutes) the batteries were depleting, the temperature of the motor was getting too high to run, it was back to the garage to recharge and cool down.
Do not recommend going over rated voltage of DC motors, but they will run with over voltage, they just get hot and will self destruct if ran too long hot. Kills the life of the motor also.
Best of luck with your project!
John


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