This forum is in read-only mode. Please continue to browse, but replies are disabled for now. Why?

Building an electric moped from scratch

I am trying to build from scratch an electric moped that can drive up to (hopefully) thirty to thirty five miles per hour for a senior project. Both my instructor and I are new to this sort of thing, so we don't know what kind of parts to buy at all. Any advice would be wonderful!

A 1000 Watt electric scooter motor could propel a moped on flat ground without a headwind to around 30-35 miles per hour. The proper gear ratio between the motor and rear wheel sprockets would be the key to obtaining this speed because the motor needs to be operating at its highest RPM in order to produce the most amount of power.

We have a gear ratio calculator designed specifically for electric vehicle projects using sprockets and chain as the drivetrain. Here is the link to it:

For the gear ratio calculator the motor speed in RPM and motor sprocket teeth information can be found in the description of the motor, for example our MOT-361000B 36 Volt 1000 Watt electric scooter motor has a top speed of 3000 RPM and an 11 tooth sprocket. The rated speed of our motors is with them under full load so the motor RPM number does not need to be adjusted. The tire diameter and wheel sprocket sizes can be experimented with until the target top speed is found. For example with a 3000 RPM motor, 11 tooth motor sprocket, 65 tooth wheel sprocket, and 20 inch diameter tire the top speed of the moped would be 30.3 miles per hour.

To electrify a rolling moped chassis the following parts would be needed:

  • Battery pack
  • Battery charger
  • Charger port
  • Speed controller
  • Power or key switch
  • Throttle
  • Electric motor
  • Wheel sprocket
  • Chain

We make custom kits that include everything needed to electrify a moped like you are building. These kits can be ordered with matching connectors installed on all of the parts so they will plug together right out of the box, or can be ordered without matching connectors installed if you prefer to do this yourself.

We can provide further help with selecting parts for the project such as what size batteries to use for the range that you want the moped to have. We also have throttles with built-in key switches and battery power meters which makes installing the electrical parts easier because they answer the question of where to mount the key switch and power meter without needing any mounting brackets or additional parts.

Please let us know if you have any questions or further information about the goals of the project and we will be glad to help.

Can you give us a list of the parts with dimensions and setup? We don't have a frame yet or something to put these parts in. and we are planning to build one, and knowing part layout and dimensions will help inform our frame design. If there was a motor that was a little stronger that would be great, if not that should work. Can we also see the kit and price for the whole kit with the matching connectors installed? This is designed to eventually become a street legal vehicle that I can use to drive around town and whatnot, if that helps you help us. Thank you for responding so quickly and with such helpful info!! It is really appreciated.

The batteries and battery charger are a large part of the cost of the kit. To help me provide an accurate price for the kit we should figure out what type of range the moped will have. A small battery pack would provide a 30-40 minute ride time and larger battery packs could provide 45 minutes, 1 hour, or longer ride times. The longer the ride time the higher the price of the parts. For example a small battery pack (30-40 minutes ride time) made of 12Ah batteries and a 1.6 Amp charger would add $145.00 onto the kit, and a medium size (45-60 minutes ride time) 22Ah battery pack and 2.5 Amp charger would add $225.00 onto the kit, and a large (1-2 hour ride time) 35Ah battery pack and 4.5 Amp charger would add $450.00 onto the kit. These ride times are calculated for flat ground riding and could be significantly increased by not running the moped at full speed, or by pedaling the moped along with the motor.

Do you know what size battery pack should be included with the kit? 

probably something pretty large, such as 2 hours or maybe even more. 

I think we may have a terminology issue, and also I changed my mind on the battery. I think the middle option, 22Ah battery pack would actually be best, and we are thinking about a scooter, rather than a moped. Hope that clarifies

The parts used to add electric power to a scooter or moped are exactly the same so everything previously mentioned still applies.

Here is a list of parts with dimensions.

  • Battery pack, BAT-12V22A, 12V 22Ah, 7-1/8" long x 3" wide x 6-5/8" high, $59.95 each x 3
  • Battery charger, CHR-36V2.5AXLR, 6" long x 4" wide x 2-1/2" high, $43.95
  • Charger port, CNX-XLR05W, 1" long x 3/4" wide x 1" high, $6.95
  • Speed controller, SPD-CT660B9, 3-1/2" long  x 2-1/2" wide x 1-1/2" high, $54.95
  • Power or key switch, between $6 and $12 depending on which one is selected.
  • Throttle, between $20 and $25 depending on which one is selected.
  • Electric motor, MOT-361000B, 4-1/4" wide x 6" long excluding shaft, 7" long including shaft, $129.95
  • Wheel sprocket, $20 and up depending on what size is needed.
  • Chain, $12 and up depending on how many links are needed.

Setup for the parts is shown in the image below.

Before you purchase the wheels and build the frame I recommend to run gear ratio calculations on the wheel size that you plan to use to make sure that the right size sprocket is available for it.

If you know the wheel size that will be used on the project then we can run these calculations and check for available wheel sprockets, or you could run the calculations yourself using our online top speed and gear ratio calculator at this link:

Please let us know if you have any questions.

I think we will use these wheels from your online store

Item # WHL-1045, item # WHL-1046, do you think those will work? Otherwise i think 12-13 inch wheels would be good. And the lower the gear ratio the better, I think, for a higher top speed. 

Both WHL-1045 and WHL-1046 are currently out of stock however we are having them produced and will be getting them back in stock in the first quarter of 2017. If this is a project that needs to be completed soon then you might want to look into using WHL-1044 and WHL-1048, or WHL-700F and WHL-700R which are currently in stock and are the same size as WHL-1045 and WHL-1046. All of these wheels are designed for and suitable to use on an electric scooter.

To obtain the highest top speed the gear ratio needs to be right for both the motor and vehicle. If the gear ratio is too low then the scooter will top out a slower speed than it is capable of, and if the gear ratio is too high the motor will be lugged and not be able to produce the power that it is capable of producing which will result in a slower speed than is possible with the proper gear ratio, and damage to the motor and electrical system from overloading it.

I ran some gear ratio calculations and found a very good combination of available parts and gear ratio for a 1000 Watt motor and 12-1/2" wheels. Here it is.

This gear ratio provides a fast top speed without being geared too highly so the motor is not lugged. It also used parts which are available and in stock. Here are the parts that I used for this calculation.

  • MOT-361000B Motor
  • SPR-844 Wheel Sprocket
  • FWM-125 Freewheel
  • WHL-1048 or WHL-700R Rear Wheel

All of these parts are compatible with each other, available, and in stock.

Please let us know if you have any questions.

Login or Signup to post a comment