Building Your Own Electric Trike: A Step-By-Step Guide

Building a 3-wheel electric bike, or trike, can be a fun and rewarding project, offering a stable and unique ride. There are several ways to build one, from using an old electric wheelchair and a standard trike to buying off-the-shelf parts. This introduction will cover the key considerations when building your own 3-wheel electric bike, including motor power, battery placement, and legal requirements. By the end, you'll have a better understanding of the process and be able to decide if this project is for you.

Characteristics and Values Table for Building a 3-Wheel Electric Bike

Sourcing parts from an electric wheelchair and a standard trike

Building a 3-wheel electric bike can be a challenging task, but with the right parts and some ingenuity, it is certainly possible. One option is to source parts from an electric wheelchair and a standard trike, which can provide a good base for your project. Here are some key considerations and steps to help you get started:

Firstly, you'll need to decide on the type of motor you want to use. Electric wheelchair motors typically have a gearbox that turns the output shaft 90 degrees, reducing the shaft speed to match the speed of a bicyclist peddling. This means you can use the original bike gearing, which is a great advantage. You can choose to use a front or rear-mounted motor, depending on your design preferences and the parts available.

The next step is to source the necessary parts. For the trike frame, you can either use an existing standard trike or build your own. As for the motor, you can source it from an electric wheelchair, preferably one with a hub to mount the wheelchair wheel. You will also need a sprocket, which can be welded to the motor hub. This step may require the help of a local mechanic or someone with welding equipment. Additionally, you'll need a battery pack, controller, and other electrical components to power your trike.

When it comes to batteries, you have a few options. You can use two 12v 50ah batteries wired in a 24v configuration, providing 24v with 50ah of storage. These batteries tend to be heavy but are also inexpensive. Alternatively, you can look for remanufactured batteries, which can help reduce costs. Don't forget to include a battery charger in your setup to keep your trike powered up and ready to go.

Lastly, don't forget the essential tools and safety equipment. Standard and needle-nose pliers, various wrenches, wire cutters, electrical tape, zip ties, and a bike lock are just a few of the tools you may need during the building process and for any on-the-road repairs. Lights, both front and rear, are also crucial for visibility and safety during your rides.

Mounting the motor and batteries

For the motor, you have a few more options. A front-wheel motor is a good choice if you're looking for assistance with grocery runs or light off-road use. This type of motor can provide power for up to 30 miles at speeds of up to 20 mph. It only requires a small sensor on the crank, making it a relatively simple option.

Another option is a rear wheel hub motor, which is often chosen for urban and hybrid e-bikes due to its increased response and quick feeling. This type of motor is placed in the rear wheel's hub, providing a quick response. However, keep in mind that this option may require a proprietary wheel specific to the brand.

The third option is a mid-drive motor, which is placed between the cranks. This type of motor is ideal for e-MTBs as it provides better weight distribution and smoother power delivery. A mid-drive motor also allows for the fitment of a standard rear MTB wheel, giving you more flexibility.

When it comes to the actual mounting process, you'll need to securely attach the motor to the frame. For example, you can attach a gear motor to the frame and then connect it to the axle with a chain. Make sure to consider the gear ratio and choose the appropriate size axle sprocket for your desired top speed. Additionally, you can wire the brake switch connector to the controller, which will turn off the motor when the brake is applied and turn it back on when the brake is released.

For the batteries, the size will depend on how much ride time you want. Larger batteries will provide more ride time, but keep in mind that this will also affect the weight and handling of your bike. SLA batteries are a reliable option, while gel batteries should be avoided as they are sensitive to overcharging and undercharging.

Connecting the electric motors to the drive

Before connecting the electric motors to the drive, it is important to assess the compatibility of the bike frame, wheels, tires, brakes, suspension system, and drivetrain with the electric motor. Factors such as power output, motor size, price, efficiency, voltage, and torque should be considered when choosing the right electric motor. For instance, a 48V 500W Front Hub Motor Electric Bike Conversion Kit may be suitable for a 20"/26"/700C wheel drive engine.

Once the appropriate electric motor has been chosen, the electric motor bracket can be installed securely on the bike frame. Following the manufacturer's instructions, the controller can then be wired by connecting the wires from the electric motor to the corresponding ports on the controller. It is important to double-check that all connections are tight and secure.

With the motor bracket and controller in place, the motor can now be connected to the bike's drivetrain. This step involves linking the power transmission of the motor to the bike's existing gear system. To do this, the chain is attached to the motor's output sprocket.

After ensuring that the motor is securely mounted and the controller is wired correctly, the electric motor will be ready to power the bike and provide an electric boost during rides. It is important to note that the process of connecting the electric motors to the drive may vary depending on the specific electric motor and bike being used, so it is always recommended to refer to the manufacturer's instructions and guidelines.

Ensuring safety and compliance with local laws

Age restrictions are a crucial aspect of electric bike safety. The minimum age to ride an electric bike varies by jurisdiction, typically ranging from 14 to 16 years old. For example, in New York State, riders of Class 1 and Class 2 electric bikes must be at least 16, while Class 3 electric bikes require riders to be a minimum of 18 years old. Understanding and complying with these age restrictions are essential to ensure the safety of young riders and other road users.

Helmet laws also differ across regions. While some states mandate helmets for all electric bike riders, especially minors, other areas may not have specific helmet requirements. For instance, in New York State, all riders under 14 must wear a helmet, and it is strongly recommended for those aged 14 and above, although not legally required. Regardless of local laws, wearing a helmet is always the safest option, and it is crucial to ensure that the helmet meets the safety standards set by the Consumer Product Safety Commission (CPSC).

Visibility is another critical factor in ensuring safety and compliance. Electric bike riders must prioritize being seen, especially when sharing the road with other vehicles. This includes using a front white light and a rear red reflector or light, with the latter being visible from at least 500 feet away. Additionally, incorporating reflective materials on the bike and rider's clothing can significantly enhance visibility. Regularly inspecting the lights' brightness and functionality is essential to ensure they meet the legal requirements.

Lastly, understanding the permitted areas for riding your 3-wheel electric bike is vital. While some states welcome electric bikes on trails and pathways, others have more restricted approaches. For example, certain states allow electric bikes on designated roadways with specific speed limits for motorized bicycles, while others may limit them to bike lanes or specific bike paths. Staying informed about the regulations in your specific state and local area is crucial to ensure safe and legal riding practices.

Building a stable and rigid structure

Firstly, consider the weight distribution across the three wheels. Unlike a standard two-wheeled ebike, which can be unstable due to a high centre of gravity, a trike setup spreads the weight more evenly, making it inherently more stable. However, you should still ensure that heavy components like the batteries are placed as low as possible on the frame to keep the centre of gravity low, improving stability and handling.

When mounting the batteries, build a boxed structure using particle board or similar material. This boxed design not only keeps the batteries secure but also adds rigidity to the overall frame. Ensure that the motor cover is easily accessible for regular maintenance. Remember to leave a slot for engaging and disengaging the gearboxes.

The motors themselves should be mounted solidly as they will be putting out significantly more force than human pedalling. Ensure that the motors are bolted securely and that the brackets or attachments are strong enough to handle the increased force. Additionally, make sure the sprockets are perfectly aligned to prevent the chain from slipping off.

Finally, pay attention to the wiring. All wiring should be neatly tied up and kept away from the chain drive for safety and to prevent interference. If using multiple motors, ensure they operate at the same speed by bolting them together and using couplers to ensure they turn in the proper direction to power the trike effectively.

Frequently asked questions