Motor

Disclaimer For The Next Sections: Motor, Battery, Controller:

I am not an electrical engineer and was disappointed at the quality of useful, integrated information regarding DC motors, controllers and batteries when used for this type of application. I believe the following 3 sections will help you decide on the size of these components and should act as a "baseline" configuration to begin your component sizing and selection.  Again, the following are the insights, rules, costs I gathered and are NOT an exhaustive treatment of this subject. But they are infinitely better than nothing!

Description

The electric motor specified here is the minimum power you will require to operate this vehicle. It is a 2000 watt (~2.5 HP), brushless direct current (BLDC), 48 volt "Vevor" brand, and was made in China. It arrived from a Canadian distributor packaged with a suitable controller, twist grip throttle, mounting bolts, and 3  motor sprockets. 

It requires a 48V Li-ion battery which is discussed in the Battery section below.  Be aware that all 4 electric motor components (motor, controller, battery, throttle) must all be compatible with each other. 

To reduce your risk, try to purchase them packaged together. If buying each separately, provide the electrical specifications of each and, if possible, try it before you buy it. A reputable supplier will agree to a demonstration/trial period + warranty.

Reasons for Motor Selection

Because the motor is the second largest cost item, and, likely, the least understood, it requires some further information. Much experimentation was completed before settling on a suitable motor. Here is a summarized log of my efforts, discoveries, and constraints . They are repeated here in order to prevent you from making the same mistakes.

1. About 2 years ago, encouraged by a few Youtubes, I attempted to convert a used automobile 12V alternator to an electric motor. When the first one installed was not powerful enough, I tried 2, each one powering a rear wheel. Both were connected to the Li-ion 48 volt battery. Both configurations failed. These converted alternators used an induced (rather than permanent) magnetic field powered by a separate 12V car battery. First 1 and then 2 motors were installed, but, even together, were simply not powerful enough and drew more amperage than the connections could handle. A converted alternator may be suitable for a single-person light electric go-kart, but not for a "young family car/light truck" like the Scottmobile.

2. Of the various motor voltages available, 60 volts DC is the maximum that a live direct current electric circuit can safely be touched by a human: 

"A touch voltage of 50 V AC (1-1000 Hz) or 120 V DC for long shock duration (> 3 s) should not be exceeded in healthy adults otherwise a life-threatening condition may occur. For children and livestock the touch voltage is limited to 25 V AC or 60 V DC."

3. There are many more powerful electric motors to choose from. Here are 2 options to the Vevor 48V used and available in Canada with costs at time of writing (202312):

Once again, you will likely find better value locally than in Canada. Here is an Indian example for about $500CDN (30,550 rupees) from NR Controls in India. The picture looks like it is heavier duty and the description would indicate it is more suited to a "less-pedalling" mode of use:

The question is obvious: "Is this extra cost worth it?"  Only you can answer that question. Here are a few sub-questions to ask:

• What is the daily range you will need? This pertains to the ruggedness of the motor as well as the battery. 

• What is the road surface - asphalt, dirt, gravel..?

• How much do the operator(s) want to peddle? 

• How heavy a load will you be moving? 

• How steep are the hills?

Of course, if you can buy a less expensive, bigger motor/controller/battery combination, go for it. The  combination I used will serve as a comparison/baseline. 

The range I get varies with all of the above, but here is a baseline comparison with a load of 1 person (the driver) on  fairly flat asphalt.