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Circus clown car convert to electric

I want to convert my gas gokart to electric.  Fully loaded with me and the dogs, it weighs less than 500 lbs and does not need to go faster than 15 mph.  We drive on level ground and only need to go around 3 miles per day at mostly walking speeds.

The rear axel has a 9" sprocket with what appears to be #40 chain and I would like to keep that sprocket and chain if possible.  I see that the motors like the the MY1020 have 8mm sprockets.  Is it possible to change the motor's sprocket to fit #40 chain, or should I replace the axel sprocket to accept the 8mm chain?

How many volts and how many watts do I need?   Is that 48 volt 1000 watt motor a logical choice?




The connector on the black and red wires labeled  '3 Motor' coming off the controller will mate with the connector on the blue and white wires labeled '2 Reverse' coming out of the junction box.  Do they go together?  



The top picture of the controller is to verify that I have things hooked correctly.  This black and red wire with female connector has ring terminals that I have connected to the center post and the side post on the controller.  Does that look correct?  

The bottom picture shows that I have two connectors that will go together, but their labels don't jive.  Do I connect '3 Motor' to '2 Reverse'?  Red and black to blue and white?

Sorry for the late reply. I was away from work on Friday and Monday so I could not answer until today.

The fiberglassed and painted piece of plywood being used as the motor and electronics mounting plate looks great.

I can see that our technician mislabeled the second 'reverse' connector and has a label that reads 'motor' on it. This connector labeled '3 motor' is supposed to have a '2 reverse' label on it, so the '3 motor' and '2 reverse' do go together.

Other than that I can see in the photos that all of the other connectors are attached to the correct locations.

I showed our technician the photo of his connector labeling mistake so he is aware of it and he apologized for the confusion that it created.


Our electric circus car has been perfect for almost a year, but the last fair grounds were bumpy and hilly grass and I think I may have burned up the motor.  I was giving it the 'gas' and it couldn't get over a hump and then a burnt smell and some smoke and now no go.  The 20amp fuse is intact.  Do I go ahead and order a new motor or is there some diagnostic tests I should do to determine if it is the motor?

Cheers Rick, great to hear from you again, although I wish it was under better circumstances.

The first thing that I would do is use my canine senses to try to sniff out the problem. It is possible that one of the parts has a distinctive burnt electronics smell to it which would be a very strong indicator of which part burned out. The likely suspects to have burned out are the controller or the motor. I would lean towards the controller having burned out since it is more prone to a quick failure than the motor is. The controller's end plate can also be removed to see inside of it with a flashlight to look for any burned electronics inside of there, and also get a better smell. If the controller smells burnt then it is almost certainly the cause of the problem.

The motor can be tested by disconnecting the two motor wires from the reverse contactor, then propping the back of the car up on something so the rear wheels are off of the ground and in the air, and then momentarily touching the motor wires to one of the batteries. Since the motor runs on 36 Volts it will not spin too fast on a single 12 Volt battery, however, if the motor spins at all then it is working and okay. 

If it winds up being the controller then it can be replaced with a new one, or if you expect to use the car in bumpy and hilly grass again, then we could upgrade the controller to a bigger and more robust model for improved power and reliability.

Please let us know how it goes and we can take it from there. 

I finally had a couple of days at home to work on our mini car and like you suspected, the controller shows signs of over heating.  I'd like to order a heavy duty replacement.  What's my next step.  Thanks!

I will start working on a heavy duty controller replacement kit and reply with a link to it once it is ready. The heavy duty controller has fewer wires and connectors than the existing controller is so there is a lot to figure out in the way of making it plug-and-play with the connectors from the existing kit. I have a photo of the old controller showing all the wires that are connected to it so I can use that as a guide. I will reply again if I have any questions or when the kit is ready. Thank you! 

That sounds great.  I ordered a new SPD-361000B today and will use that until your heavy duty unit is ready.  Is there a way of protecting the stock controller with fuses? 

I got my new SPD-361000B controller and I have things hooked up, but still not working.  The new controller doesn't have the labels that the original one did and I'm not sure what I'm doing.  The battery terminals spark if I disconnect either a pos or neg wire, even though nothing to my knowledge is drawing current.  Does this mean anything?   I connected the on/off switch to the controller terminal that looks like the connection on my original setup and the volt meter and indicator light stay on no matter the switch position.  Is that a clue?

I moved the volt meter and indicator light to a different connector and now they seem to function correctly.

The motor runs if connected directly to a battery.  I'm guessing that the problem is either in the controller, the reverse relay or the throttle.  What do I do next?

The sparking encountered when connecting or disconnecting the battery terminals is normal, even when the controller's power switch is off or not connected to the controller, so that perfectly normal and nothing to worry about.

The connectors and wire colors should be the same between the original SPD-361000B controller and the new one, however, the new controller will not have the custom labels on it that the original controller has. All but three of the connectors should be able to be identified by their unique wire colors and number of wires. The exception to this is the three 2-terminal connectors with thin red and black wires, and two of those should have factory labels on them which read "charging port" and "brake light" indicating which parts connect to them. The third connector with thin red and black wires which has no factory label on it is for the power light. 

The wiring pinout for SPD-361000B is available on this page for further help with the connections:

The on/off switch needs to connect to the connector on the controller with one thin red and one thin blue wire going to it.

If the indicator light stays on no matter what the power switch position is that might indicate a faulty switch or short circuit in the wiring between the switch and controller. To test for this type of problem unplug the power switch from the controller and see if the indicator light turns off then.

Regarding the motor not running that could be caused by a problem with the throttle wires such as a broken wire or bent connector terminal. Unplug the throttle and check for any bent terminal pins inside of the connector and inspect the wires between the throttle and controller. Another thing that could cause the motor to not run is a bad connection between the reverse contactor and controller so check that connection well.

Feel free to attach a photo of the installation if you would like for us to look at it before making the final connection to the battery pack, or if it still does not work.

Please let us know how it goes and we can take it from there.

Just read your latest post. Glad to hear that the Voltmeter and indicator light are functioning properly, that also indicates that the power switch is working and plugged into the right connector.

The motor should run though. Regarding the reverse relay, do you hear it clicking when the direction switch is changed between forward-park-and reverse positions?

Yes, the relay clicks as I move the switch from forward to reverse.  I don't have the charging port connected to the controller at this time.  Since I don't have a connector for that connection, I will hard wire it when the time comes.  Would not having the charging port connected to the controller be a problem?

The throttle connector looks OK.  No bent pins the three wires look to be intact all the way to the pedal.  

Having the charger port not connected to the controller will not affect if the motor runs so that cannot be causing the problem. The reverse relay clicking is a good sign so we do not have to think about the reverse relay or direction switch causing the problem. 

It is usually the simplest thing that causes something to not run so let's start off in that direction. How about the connector between the reverse relay and controller - the one which previously had a meltdown. I would check to make sure that the new connector's terminals are properly connected to the wires. Make sure the insulation was stripped off the wire before the terminal was crimped on, make sure the crimp is tight enough to make contact with the copper wire, and so forth. 

If a brake switch (or anything else) is plugged into the controller's "brake lever" connector - the one with a thin yellow and thin black wiring going to it - then unplug it from the controller to make sure it is not causing the problem. 

If still no luck then carefully scrutinize the throttle wires and connectors for any signs of something that could possibly be wrong such as a pinched or broken wire, bent over terminals, loose connectors, et cetera. 

If none of this gets the motor running then there are further troubleshooting procedures which require a multimeter to perform which we can suggest to help pinpoint where the problem is.

Please let us know how it goes and we will take it from there. 

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