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Electric Go Kart Project - Help sizing system

I am working with my 13 year old son to setup a electric go kart. We currently have a rolling kart and essentially need all the electrical components: Motor, Speed controller, Wiring, batteries, charger, charger port, foot pedal, key switch, fuse, etc...

The kart currently has a 60 tooth sprocket with a #35 chain. Also, the size tires on it are 11 - 11.5" in diameter.  I would like the kart to have some zip and top speed between 20 - 30mph. Additionally, I would like the battery life to last ~ 45 minutes or so.

I saw a previous kit that was assembled and wondering if this KIT-159 would be a good fit for my needs:

Also, I would like to have a speed limiter, in the event the to speed is too high. I saw this part, and was wondering if this THR-ADJUSTER would be a good fit with the kit:

One other nice to have, would be the option to connect 12v accessories(lights and/or horn). I believe the kit above has a converter included to address that, however I am not sure how the wiring works for that.

I am open to other kits or suggested changes. Please let me know your thoughts.

Thanks in advance!

Also, I'd like to add a voltmeter like MET-120V-RED: . For this, the speed limiter, & the 12v accessory converter I am not sure how the wiring would work. Is there anything you could point me to? Thx.

I ran some Gear Ratio Calculations and found that with a 60 tooth axle sprocket and 11.5" wheels the top speed is around 17 MPH. For a top speed of 25 MPH an axle sprocket with around 40 teeth would be needed. Here are the calculations:


It sounds like KIT-159 would work good for your project. The 22Ah batteries in this kit would provide around 60 minutes of Ride Time on flat ground.


KIT-159 has a 3-position key switch which turns the power off, on, and activates reverse (off - on forward - on reverse). With a kit that has reverse relays such as KIT-159 the go kart has to be at a complete stop before switching from forward to reverse, or reverse to forward, otherwise the controller will become damaged.

If you do not need reverse then we could make a kit without reverse which would cost less. If you prefer toggle switches to a key switch we could make a kit like that also.

We can make a kit with two toggle switches for power and reverse along with a motor reversing contactor that would stop the motor between switching from forward to reverse. This type of kit would be more reliable than a kit with reverse relays because the chances of the controller being damaged from switching directions when the go kart was moving would be significantly lowered. The go kart would still need to be completely stopped before switching from forward to reverse, or reverse to forward, because the motor reversing contactor puts an electrical brake on the motor between its forward and reverse positions.

We can add a Voltmeter to any of our kits.

Please let us know your thoughts on which type of kit you would like. Non reversing? With key switch and reverse relays? With toggle switches and motor reversing contactor?

Thank you for your response! Prior to your reply, I was anxious to get moving so I made an order already. The kit-159 was not available due to the relays not being in stock. So, I basically bought each of the parts in kit-159 minus the relays. Regarding reverse,that is an important feature we would like to have. I am a bit unclear about how and why the relays are needed when using the key switch for reverse. You bring up a good point that I was not aware of, that if someone switches from forward to reverse while going it will damage the controller. If this is the case, I would want to eliminate that possibility and that would be my primary goal. Seems like one option may be to just wire the key switch I bought, to only go forward (i.e. - not connect a wire to reverse tab of the switch) and then add a reverse switch ( between the controller and motor. Would this work and achieve the goal? Alternatively, you mentioned toggle switches as an option, but I am unclear on how that would work, if relays are needed and if it helps prevent controller damage. Any additional insights and your recommendation on best option to solve the reversing solution would be greatly appreciated. Thanks!
I just placed a temporary shipping hold on your order in case we need to add a new part onto it, or cancel it so you can order a kit. I can remove this shipping hold at any time on your request. I just wanted to make sure that your order does not ship out before I provide this new information to you.

Our SWT-715 reverse switch is an okay option to add reverse to a go kart. This reverse switch requires a fair amount of force to turn the knob so it would be difficult to accidentally put into reverse. However the down side to this switch is that four thick gauge motor wires would need to be routed to and from it, so if it is a few feet away from the motor and controller then a lot of thick wire will be needed to wire it. It is also fairly large and not the easiest switch to mount.

Toggle and key switches are easy to install compared to our SWT-715 reverse switch.

One kit we have that is in stock and I think may be perfect for your project it KIT-361000-01. Here is the link to it:

KIT-361000-01 uses toggle switches for power and reverse which have thin gauge wires running between the switches and controller/relay. It also has an extremely heavy-duty reverse relay which applies an electrical brake to the motor between forward and reverse (it has a park position) which makes it very difficult to damage the controller if the switch is accidentally moved from forward to reverse while the kart is in motion. However this heavy-duty reverse relay is best suited for toggle switches and can not easily be used with a key switch. If absolutely necessary we could make this kit with a key switch as the power switch though. This would require a couple of extra Bosch type relays to wire to the key switch and some extra labor which would raise the price of the kit a little however it is possible.

We also have this same kit available with a key switch which is wired for off-on-reverse. The key switch has thin gauge wires between it and the controller/relays. It uses two Bosch type relays for reversing which do not provide a park mode between direction positions so with this setup it would be easier to damage the controller if the key was turned to the reverse position when the kart was in motion. We could also modify this kit to have a key switch for power and a toggle switch for reverse. This kit cost a little less than the 01 kit because it does not have the heavy-duty reverse relay in it.

This is our kit # KIT-361000-02. Here is the link to it:

Please have a look at these kits and let us know how you would like to proceed?

Great, thank you!  In this case, I like this option.

However, I actually already have the batteries. Therefore, would you be able to make the same kit minus the 3 batteries? If so, this will allow me to select the proper wire lengths for the kit and I will purchase that. And we can cancel the order that you placed on hold.

Thank you!

Yes that is no problem. I will make a version of the 01 kit without batteries. I will post a link to it here in a few minutes.
Here is a link to the kit without batteries:

I cancelled your previous order and refunded the payment back to your PayPal account.

Please let us know if you have any questions, or would like any changes made to the kit.
I just noticed that your previous order had a Throttle Top Speed Adjustable Limiter in it. If you still want this part then you could order it along with the kit and we would wire it to work with the kit.

Great! Thank you for creating the new kit. I will hold off on the speed limiter and see. If I feel it's needed, I can come back and order it in the future.

Thank you!

I forgot to mention that I did purchased the latest kit you assembled for me. Thank you!

I see your order for the kit item # KIT-361000-01-NB in our system. We will start building it on Monday. Thank you for your order - we appreciate your business.

We received the kit and were able to get it up an running over the weekend. I just had a couple of questions:

1) Is there any difference in speed or torque with forward vs reverse? The reason I ask, is that when we wired it up per all the labels, when the switch was in "F" the motor went in reverse. So to fix this, I swapped the motor cables that connect to the reverse relay. By doing this, it did correct it, so now when the switch is on "F" it goes forward. I was just wondering if that was the correct way to fix it and if there is any difference in foward vs reverse(either by the motor or how the controller distributes power to the motor).

2) Could hot weather cause the fuse to blow? On Sunday, it was ~103 degrees out. My son was driving the cart for about 5 minutes and then the main 40Amp fuse blew. I am wondering if this was due to the extreme heat or if there is something else I should be investigating.



Our non-gear motors are designed so that clockwise rotation of the shaft as you are facing the motor is forward, and counterclockwise is reverse. The difference in speed and torque between forward and reverse depends on if the motor is neutral timed or forward timed. The motor manufacturer does not provide us with their motor's timing specifications so that is something that would need to be tested in the field to discover.

I have not heard of hot weather being the cause of a blown fuse. It is more likely caused by an overload of the electrical system. Overloads can occur when the gear ratio is too high for the conditions that the vehicle is being driven in. I am not sure what the gear ratio of the go kart is or what the terrain is like that it is being driven on. If you could let me know the number of teeth that the axle sprocket has and what type of terrain the go kart is used on then I could run some calculations to check and see if the gear ratio is a good match for the terrain.

Thank you. The Axel sproket has 60 teeth and the motor sprocket has 11 teeth. Tires are about 11 to 11.5 inches. Lastly, the driver weight is about 110lbs. The fuse blew while driving on flat surface/no hills.

Thanks in advance for your help.

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