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Complete Electric Kit for a Miniature Car

I am in the beginning stages of building an electric powered Mustang Junior reproduction car and would like a complete plug n play electric kit as the power train. The car is a 1/4 size of the actual 1967 Mustang and were often driven in parades by Shiners. The vehicle will weigh in at around 400 lbs when finished (including the weight of driver). An photo of a gas powered version can be found on the website location http://www.jrcentral.com/images/my67f.jpg

The rear wheel on this vehicle will be approximately 12" in diameter and will be fitted with a 60 tooth sprocket (#35 chain). I am looking for a system/kit with the following demands/requirements:

1) Foot pedal throttle

2) Keyed switch for on/off (will go on the dash)

3) Toggle or rocker switch for forward/reverse capability (will also go on the dash)

4) Appropriate sized electric motor and sprocket (#35 chain) to have a maximum speed of 18- 20 mph and to function well at lower speeds (so that the motor isn't lugging or heating up)

5) Appropriate battery package for the vehicle to run for 60-90 minutes

6) Battery charging system

A plug and play kit from your company would be awesome. I look forward to your reply.

Future additions may include a functioning horn, functioning headlights and brake lights.


We look forward to making a kit for your project.

The 60 tooth rear sprocket and 12" wheel diameter are the perfect size for an 18-20 mph top speed. For that top speed a 1000 Watt motor would have the right amount of power. Our 1000 Watt motor have a 3000 rpm output speed when under load. I ran some calculation using our 1000 Watt motors along with a 60 tooth rear sprocket and 12' wheels and found that with a 10 tooth motor sprocket the top speed would be around 18 miles per hour, and with an 11 tooth sprocket the top speed would be around 20 mph. Here are the calculations.


Our 1000 Watt motors come with sprockets for 8mm chain, however the original 8mm chain sprocket can be removed and a sprocket for #35 chain can be installed. The sprocket for #35 chain will need to have a 12mm bore which is not a common size, so one of our #35 chain sprockets with 3/8" bore would need to be drilled or machined out to 12mm to make it fit the motor. We have #35 sprockets with 3/8" bore available in 10 and 11 teeth sizes. 10 tooth sprockets for #35 chain with a 12mm bore are commonly available at restaurant supply stores under part number Nieco 13770, however they cost around $30-$35 so if you can bore out one of our $10 sprockets with 3/8" bore to 12mm then a good amount of money could be saved on the sprocket.

Everything else that you mentioned is possible including the reverse switch function.

The one thing left to figure out is the size of the battery pack. If the car is run at full speed all the time then it will require a battery pack that is twice the size as if it was run on average at half speed. So determining what the average speed will be is necessary to calculate the right size battery pack. I need to ask a couple of questions to figure out the battery pack size.

Is the 60-90 minute run time on average while driving the car at full speed, half speed, walking speed, or???

Do you want the 60-90 minute ride time to be for driving primarily on flat ground, or for driving on flat ground most of the time and up hills or grades occasionally? (100% flat, 90% flat/10% uphill, 70% flat/30% uphill, etc.)

Thank you for the very quick response. To answer your questions, the 60-90 minute run time would be at half speed on average and that it would be driven on flat ground 95% of the time and very minimally on any grade uphill or downhill. I think that the 11 tooth sprocket would be fine and that I have some local buddies who would be comfortable in boring the sprocket out from 3/8" to 12 mm.

I look forward to seeing the package that you are able to put together. In browsing the parts, I am interested in the Premium Foot Pedal Throttle to be in the package if possible.

Looking forward to moving forward with the project.


We have 1000 Watt 3000 RPM motors available in both 36 Volts and 48 Volts. A 36 Volt system would require three batteries while a 48 Volt system would require four batteries. I usually opt for a 36 Volt system when it is possible to keep the number of batteries down to save on initial and replacement battery costs. Sometimes like in the case where two batteries need to be on one side of the vehicle and another two need to be on the other side then a 48 Volt system is best so the weight is equally distributed. If the battery pack will be in the center of the vehicle then it does not matter though and a 36 Volt battery pack can be used.

With a 36 Volt battery pack, for the run time that you want the car to have, three 12 Volt 22Ah batteries would be optimal and should provide around 90 minutes or more of run time at half speed. Another option would be three 12 Volt 15Ah batteries which should provide around 60 minutes of run time at half throttle. The 22Ah batteries are larger and heavier than the 15Ah batteries so if space to mount the batteries is an issue then that will need to be taken into consideration. Here are the dimensions and weights of these batteries:


So I can make the kit, would a 36 Volt or 48 Volt battery pack would be better for your build, and what size batteries would work best?
Let's put the kit together with the 22 ah batteries. Weight distribution isn't a major factor as the car's steering wheel is offset to the left (mimicking a real car) so the batteries on the right side will displace some of the driver weight. I couldn't see the 11 tooth #35 3/8" sprocket on your website (needed to be bored out to 12 mm). I trust that you have access to this item. I look forward to seeing the price on this kit. Jim
Forgot to stipulate the 36 volt system.
I added the 11 tooth sprocket for #35 chain to our website and it is item # SPR-3511A. I found out that it has a 5/16" bore instead of 3/8" however since you will be boring it out to 12mm this does not matter. I added the sprocket to your kit.

I went ahead and made a kit for your project which is our item number KIT-158. Here is the link to it: https://cart.electricscooterparts.com/ProductDetails.asp?ProductCode=KIT-158

I can still make any changes to the kit that you would like so please have a look at the kit and if there are any parts that you would like to change then please let me know.

If you prefer a toggle switch for reverse we can do that however it requires us to make a custom wiring harness for two relays which takes around an hour of time so the cost would be $50 more for parts and labor. The toggle switch would be a lot easier to mount than the large rotary switch though, and easier to use. If you do want a toggle switch for reverse then please let me know and I will modify the kit to have it.

Please let me know if you have any questions.


I have looked at the kit and am wondering what the item to the left of the key switch is? Does the kit accommodate forward and reverse? Would a 3- way key lock achieve this? All in all, I am please with the kit and price. Looking forward to your reply as I am anxious to move forward.


Re-read the your post. I would prefer a toggle switch for forward and reverse in place of the larger item pictured in the kit. My question above, would a three way key switch accommodate reverse-off-forward similar to a mobility scooter? This would eliminate the toggle switch for forward/reverse selection. Your thoughts.

Yes we can make the kit with a 3-way key lock that activates reverse. We can not make the key switch with reverse-off-forward positions because the key is only removable in the far left position, however we could make it with off-forward-reverse positions. Would a key switch with off-forward-reverse positions be okay with you?


Yes, this configuration would be perfect. Update the kit information and price and I will place my order when I have the new information.


I just finished making the new kit with a key switch for power and reverse. The item number is KIT-159. Here is a link to it: https://cart.electricscooterparts.com/ProductDetails.asp?ProductCode=KIT-159

Please let us know if you have any questions.


Thanks for the update, will be placing my order right away! Thank you for your time and patience. Designing this system, with the minor tweaks along the way, was made very easy by your expertise!


I see your order in the system so it went through. Because of the reverse relays and key switch custom wiring this kit might take a day or two longer for us to make than usual, however we should have it shipped out within 2-3 business days.

Thanks for your order and please let us know if you have any questions after the kit arrives.

Jim, I'm working on a Mustang Jr. project as well.  I would love to hear your thoughts on this kit as it appears very economical and easy to put together.  I'm planning a jack-shaft and dual wheel drive.

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