Gas to Electric GoCart Conversion - 150cc 2 Seater Gocart.

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

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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.

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    51 Discussions


    5 years ago on Introduction

    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...


    5 years ago

    how muchh is the plate


    5 years ago on Step 4

    add a solar set up of some kind that will allow u to trickle to full out charge your bike.


    8 years ago on Step 3

    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.

    1 reply

    5 years ago on Introduction

    Awesome work! What's the power difference between the gas and electric motor?


    8 years ago on Introduction

    i swear i saw the exact same thing on craiglist for 750 its a roketa something A.K.A cheap crap


    8 years ago on Introduction

    wow, you are smarter than I... that is amazing... the reason i come to this site is to see things like this.


    8 years ago on Step 2

    A picture of the mounting plate would be nice here!


    8 years ago on Step 3

    I don't soppose i could get a diagram of your wiring?


    8 years ago on Introduction

    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.


    8 years ago on Step 3

    Hello, Nicholast I like your electric conversion,
    now in a electric mode did you field a power loose
    against the old gas powered mode?
    I think you could use to sopport the electric engina a scisors bolt floor jack whit rubered soports
    ¡ congratulations ¡

    de tizzyjuliegfoster

    Reply 9 years ago on Step 5

    did you make it yet mine go faster 80mph and i put music in mine and add me as a friend1


    Reply 8 years ago on Step 5

    It was a throttle box for an electric car, I just attached the old throttle cable to the box.


    10 years ago on Introduction

    Is this street legal where you are? In Idaho it would be for city streets and secondary highways -- with licensing.

    2 replies

    Reply 10 years ago on Introduction

    I have not checked yet lol No one has ever bothered me because of where I live (middle of nowhere)

    2 stroke nicholast

    Reply 9 years ago on Introduction

    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