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I have a 150cc 2 Seater gas gocart that I used for about 2 years. The starter motor stripped a gear 3 months ago and I decided to convert it to Electric Power rather than fix the gas engine.


Parts list:

Controller - $300
Motor - From old golfcart ($600 in store)
Wire - $20
Misc nuts/bolts - Already had them ($30 in store)
Contactor - $25
Diode and Resistor - $10
Sprocket - $35
Aluminum Plate and Bar - Already had in my garage.
Misc stuff that I had - $10-50

Step 1: Motor

The label is worn off the motor casing but as far as I can tell its specs are as follows:

Type: Series Wound DC Motor
Max Current: 300A
Cont. Current: 100A
Voltage: 36
Max HP: 15
Cont. HP: 5
Length: 14"
Diameter: 7"
Weight: 30Lbs


It was pretty rusted up and the pulley that was on it was a pain to remove. I took the motor apart and cleaned the dirt out of the coils, brushes and also greased the bearings.

Step 2: Motor Mount and Sprocket

Mounting the motor was mostly easy, there were a few hiccups on the way. The biggest one was that the motor has a tapered shaft and finding a sprocket that would fit was impossible.

I ended up buying a standard 1/2" 9 tooth sprocket and machining the inside out on a lathe, to a taper that would fit on the motor shaft.

The mounting plate consists of a 1/4" aluminum plate bolted to the frame, with a 2x1 piece of aluminum bolted to the back of the plate like a clamp to prevent the plate from flexing under the torque of the motor (300A makes an amazing amount of torque on a Series Wound motor).


If your wondering what the 2x4 piece of wood is for, I found out that the steel motor mount that was welded to the motor was not strong enough as the motor is designed for the plate to be bolted to the front with the shaft going through the plate. I didn't realize this until i took it out for a test run and it flexed so much that the chain would slip over the sprocket.

Step 3: Electronics

I used an Alltrax Series Wound Brushed DC Motor Controller (about $300) specs are:

Max Current: 300A
Cont. Current: 100A
Max Voltage: 50V
Min Voltage: 20V
Throttle Type: 0-5k


The power system uses 4 Gauge wire. They will get a little warm to the touch after doing donuts for awhile.

The contactor was left over from another project, this one is overkill and you really only need about a 150A contactor. but make sure that the coil rating is the same or a little higher than your system voltage or it can melt. (500A/48V)

The controller contains capacitors to smooth out the power flow. If the controller has no voltage on it and you apply power quickly it can destroy the controller. The Precharge Resistor keeps the capacitors charged even when the key is off. (20ohm/25watt)

When the contactor turns off, the coils create a huge burst of high voltage. The reverse protection diode stops this voltage from getting to the controller and damaging it. (600V/5A)

Step 4: Battery Pack

The current battery pack I am using is a Lithium Phosphate 42V/33AH system.

Later on I am going to switch to a 48V/110AH lead acid battery pack for more range and better reliability.

Specs are:

Capacity (WH): 1.3KWH
Voltage: 42V
Capacity (AH): 32AH
Max Current: 800A
Cont. Current: 400A
Weight: 28Lbs


It has a charger (120V ac) that will give a full charge in 6 hours.

The pack has a control board in it to protect from over charging/discharging and overcurrent. It also keeps the cells balanced which is crucial for a Lithium battery pack.

Step 5: Testing/Performance

I have tested everything from current consumption to 0-20 mph times

Top Speed: 22MPH
0-20 Time: 5.6 Seconds
Current @ 10MPH: 40A
Current @ 20MPH: 120A

Steepest hill here is about a 50 degree incline, it will climb at 15MPH at full throttle (about 270A)


Anything missing or that you want to know? Please let me know! by commenting me, PM me or emailing me at wolfcry0 at gmail . com

You can also talk to me on AIM @ wolfcryo if you have any questions.

<p>I wan to make a electric car for mechanical project I need a dc motor less than equal to 3000 w max rpm 3600 max torque 12.8nm at 2400 rpm power consumption max 48 volt can u recomend me some motor name or link which would suit best for me....thanx in advance...</p>
how muchh is the plate
<p>add a solar set up of some kind that will allow u to trickle to full out charge your bike.</p>
I am currently looking at rebuilding my two electric golf garts with custom frames both have 36 volt systems currently (the only thing usable in the electrical system is the 36 volt motor and the batteries) i am looking for information on what to buy for a controller and contactor as well as anything else i might need to run them (they both have good hydralic brakes) thanks for any help here.
<p>look up the make and model of your golf carts</p>
<p>Awesome work! What's the power difference between the gas and electric motor?</p>
i swear i saw the exact same thing on craiglist for 750 its a roketa something A.K.A cheap crap <br>
wow, you are smarter than I... that is amazing... the reason i come to this site is to see things like this.
A picture of the mounting plate would be nice here!
I don't soppose i could get a diagram of your wiring?
I wonder if you could hook up a 2 to 1 gearbox, where you have 2 motors, that drives one drive shaft. It would draw more power, but you could likely put another battery on it as well. But with that setup, you could gear it for higher speeds, as the two motors could easily compensate for the added strain for lower speeds, and starting from a stop. Something to consider.
Hello, Nicholast I like your electric conversion, <br>now in a electric mode did you field a power loose <br>against the old gas powered mode? <br>I think you could use to sopport the electric engina a scisors bolt floor jack whit rubered soports <br>&iexcl; congratulations &iexcl;
how long can you go on a charge?
About 20 miles
<p>did you make it yet mine go faster 80mph and i put music in mine and add me as a friend1</p>
what type of throtel did you you use?<br>
It was a throttle box for an electric car, I just attached the old throttle cable to the box.
Is this street legal where you are? In Idaho it would be for city streets and secondary highways -- with licensing.
I have not checked yet lol No one has ever bothered me because of where I live (middle of nowhere)
i live in the middle of a huge feild but i dont own the field it just me and my neighbours lol my neighbours are pretty cool with us too
what kind of cart was it<br /> <br />
Sunner 150cc i think, its Chinese.<br />
I wish there was more explanation of the control system. I am not an electrical engineer so I don't really appreciate the logic of the circuitry. Is there a elctric 101 for dummies?<br /> <br /> It is a very interesting project.<br />
you should think about adding some solar panels to the top it would be a greener way of keeping the battery charged.<br />
I could, but it is after all a gocart and I would be too worried about them getting damaged by flying objects or something like that.&nbsp; Maybe mount them to a post in the ground and charge it from there.<br />
My experience with solar panels is limited, pretty much, to what I've read on this site, so I'm not sure how large the panel would need to be to power your cart.&nbsp; But I was just thinking that you could basically make a thin case for the panel with a plexiglass top to protect it.&nbsp; It wouldn't be able to take a large perpindicular force to the plexiglass, but would it really need to?&nbsp; As long as it can deflect the rocks that might get kicked up from time to time.
You could charge the batteries using one, but it would take more than a few days for a full charge. <br /> <br /> And to power the motor you would need a massive bank of panels, for comparison a typical solar system that goes on a house is 5KW, this gocart needs up to 20KW or 4 times the power of a normal house.<br />
So its basically a golf cart with a diff body still freaking awesome<br />
haha almost, but it has better suspension and very heavy drive axles to handle the bumps and torque.<br />
Where does the precharge resistor hook into?<br />
It goes across the main contactor/relay terminals.&nbsp; Basically keeping the voltage in the controller the same as that of the battery.&nbsp; Preventing a spark or arc when the power is turned on.<br />
Lead acid are known for dying quicker because of impacts, jolts and bumps. It would be better (yet quite a bit more expencive) to use a nickel chemistry battery. It would also be lighter for the same AH. Great instructable btw.
Your definitely right about the NiMH battery's I don't want to spend the money on one right now and 4 deep cycle 12V 110AH lead acid battery's cost about $300 here which is cheaper than a NiMH pack. Also it gets quite cold here and NiMH battery's can have issues with temperature.
Lead acid batteries can freeze and split... its happened in my truck before... it was an epic mess, there's still a ton of rust...
They generally only freeze if the specific gravity of the cells is too low, which increases the freezing temperature.
I haven't had any problems with my golfcart in the winter. It doesn't get cold enough to damage them here.
i think that the batteries should not be set that high. the lower the cg the better for saftey and etc.
That was in the plan originally but there's really no room anywhere lower down besides maybe the passenger seat, but i wanted to keep that free.
Do you think a 4200rpm 7hp 48v golf cart motor woud work well on a small 1 seater go cart? I am trying to build one, and my neighboorhood is very hilly, so i'm trying to get something that can go relativley fast (maybe 25+) an do moderate inclines.
It should work quite well for a small gocart, is the HP rating continuous or a peak rating? Does the motor have current (amps) specified on it? If its a golf cart motor its probably 7hp continuous which should definitely get you to 25mph.
there's no battery cost listed in the parts list. Where did you get your battery and how much did it set you back?
I did not order the battery so I don't know the manufacturer of it, I do know that they are in China and its not hard to find a place to make one if you look around. The cost was around $1500 iirc
Can I have the old forgotten engine? :'(
What is the C rating on you LiFePOs?
Around 20C Continuous. 30C Burst. Thats ~1000 Amps at 36 Volts, and you need huge wire to carry that. The GoCart only uses about 10C Burst.
what type og go kart is it as in brand and name?
Its a Sunner 150cc, the company is in china and their website is pretty hard to find.
Cool mod! How much runtime do you get out of a full charge with that setup?
With the lithium phosphate setup, I get about 2 miles. Keep in mind that I'm only using that battery for testing and the new pack should be 10-15 miles.
cool, this is pretty much basic instructions to mount an electric motor to anything to drive it, which is what I was looking for, thanks 5 * and favorited<br/>

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Bio: I am 19 and have been homeschooled my entire life. I spend most of my time making and designing things with parts I have lying ... More »
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