Building My First Electric Bike: A Personal Journey

Building an electric bike can be a fun and rewarding project for anyone looking to reduce their carbon footprint or simply enjoy a faster commute. In this article, we will delve into the step-by-step process of converting a traditional bicycle into an electric-powered vehicle, discussing the necessary components, the benefits of electric bikes, and the challenges faced during the building process. We will also explore the different types of motors and batteries available, and provide tips on choosing the right bike for conversion. By the end of this article, readers should have a clear understanding of how to build their first electric bike and be well on their way to experiencing the thrill of electric biking.

Choosing the right bike

When choosing a bike, it is important to consider the type of frame and fork. The frame should be strong, and mountain bikes are commonly used for electric bikes due to their sturdy frames. It is recommended to avoid bikes with carbon fibre frames or forks, as they may not be strong enough to support the extra weight and handle the extra torque of an electric bike. Additionally, look for a bike with a standard bottom bracket width of 68mm, as this is the size that most conversion kits are designed to fit. If you plan to use a mid-drive motor kit, avoid investing in a front derailleur or a bike with a double or triple crank set-up, as these components will need to be removed. Instead, look for single-speed bikes or fixies. However, keep in mind that fixie bikes often lack eyelets for rack attachments.

Another important consideration is the type of brakes and handlebars. It is recommended to choose a bike with front disc brakes, as they provide better stopping power, especially on steep hills. Wider handlebars are also preferable, as they offer more room for accessories and lights. If you live in a place with many bike paths and lanes, like Eugene, Oregon, an electric bike can be a great way to take advantage of those paths and explore your surroundings.

Once you have chosen the right bike, the next step is to gather the necessary supplies, including a conversion kit and a battery. You can find conversion kits online, and they typically include a throttle, speed controller, and a wheel with a hub motor. Make sure the kit you choose includes a wheel that matches the size of your bike's existing wheels. With the right bike and supplies, you'll be well on your way to building your first electric bike!

Selecting the motor

The most popular choice for electric bikes is the hub motor. Hub motors are located in the centre of the wheel and come in two varieties: geared hub motors and direct-drive motors. Geared hub motors are known for their high torque and hill-climbing abilities, making them suitable for hilly areas. They are also efficient at regenerating energy when riding downhill or braking. However, they tend to be heavier and less durable than direct-drive motors. Direct-drive motors, on the other hand, are lightweight, durable, and require minimal maintenance. They are ideal for commuting on flat terrain but may struggle with steep hills.

Another option is the mid-drive motor, which is a relatively newer type of electric motor. Mid-drive motors are located in the bottom bracket area of the bike and provide power directly to the drivetrain. They offer a more natural riding experience and efficient power transfer, making them suitable for off-road and hilly conditions. However, they tend to be more complex and may require modifications to the bike frame and drivetrain.

When selecting a motor, it's important to consider factors such as power output, efficiency, weight, and compatibility with your bike frame and wheel size. The power output of the motor will determine the top speed and acceleration of your electric bike. Efficiency is also crucial, as it will impact the range and battery life of your bike. Additionally, consider the weight of the motor, especially if you plan to carry your bike or ride without electric assistance occasionally. Ensure that the motor is compatible with your bike frame and that the wheel size matches the existing wheels on your bike.

By carefully considering your needs and the characteristics of each motor type, you can make an informed decision about which motor will be the best fit for your electric bike build.

Installing the conversion kit

Firstly, it is important to select the right bike for the conversion. Mountain bikes are the most common choice for electric bike conversions due to their sturdy frames and standard bottom brackets. It is recommended to avoid bikes with carbon fiber frames or forks as they may not adequately support the additional weight and torque of the electric components. Wider handlebars are preferable as they provide ample space for accessories and lights. Front disc brakes are also advantageous, especially when navigating steep hills.

The next step is to prepare the bike for the conversion. Remove the chain, front crankset, and bottom bracket. If using a mid-drive motor kit, it is not necessary to invest in a front derailleur or a bike with a double or triple crankset. Single-speed bikes are a good option in this case.

Once the bike is ready, the installation of the conversion kit can begin. The first component to install is the tire from the old bike wheel onto the new wheel with the hub motor that is included in the kit. This step ensures that the new wheel is ready to be mounted onto the bike. Secure the speed controller, which regulates the bike's speed, to the frame of the bike above the chain. This placement ensures easy access and control during rides. Attach the throttle to the handlebars, allowing for easy control of the speed while riding.

The following step involves connecting the battery, which is a crucial component, to the speed controller and throttle. The battery powers the entire system, and a 36- or 48-volt battery is typically recommended. The battery is usually mounted on a rear wheel rack or a cargo bracket above the rear wheel, enclosed in a plastic case or a fabric carrying bag to protect it from the elements. Ensure that the battery is securely mounted to prevent any movement or vibrations during rides.

Finally, it is essential to test the bike after the initial installation. Take the bike for a short ride and make any necessary adjustments. It is common to need to adjust the brakes, throttle control, and speed controller to ensure optimal performance and safety.

Building an electric bike using a conversion kit is a rewarding project that can result in a powerful and reliable mode of transportation.

Adding the battery

Choosing the Right Battery:

Firstly, you need to select an appropriate battery for your electric bike. The most common voltage options are 36V or 48V. A higher voltage battery, such as 48V, will provide more power and a longer range but will also be more expensive and heavier. Lithium-ion batteries, like the one used in the Colorado University Mechanical Engineering project, are a popular choice due to their high energy density and lightweight properties.

Battery Placement:

The placement of the battery is an important consideration. Most electric bike builders choose to mount the battery on a rear wheel rack or above the rear wheel on a cargo bracket. This location provides a good balance between weight distribution and ease of access for charging and maintenance. Ensure that the battery is securely attached to the rack or bracket to prevent any movement or vibrations while riding.

Connecting the Battery:

Now it's time to connect the battery to the other components. First, you'll need to connect the positive and negative wires from the battery. Solder these wires for added strength and durability. Then, use small lightweight crimp connectors to join the wires. Finally, heat shrink and wrap the wires with electrical tape to create a neat and secure wiring harness.

Testing and Maintenance:

Once the battery is connected, test the bike to ensure everything is functioning properly. Remember that you may need to make adjustments after your first ride, so don't overtighten any connections or fittings. Regularly check the battery connections for any signs of wear or corrosion and keep the battery charged according to the manufacturer's recommendations.

Building your own electric bike can be a rewarding experience, and adding the battery is a crucial step in bringing your project to life. Remember to follow safety guidelines and best practices when working with electrical components, and always wear a helmet when riding your electric bike.

Testing and troubleshooting

Before you begin testing, ensure you have all the necessary safety gear, including a helmet, eye protection, and gloves. It is also recommended to have a first aid kit nearby in case of any minor injuries. Choose a safe, open space away from traffic and pedestrians to conduct your tests.

Start by performing a static test, inspecting all the connections, wires, and components to ensure they are secure and properly installed. Check for any loose wires, frayed cables, or damaged parts. Pay close attention to the battery connections and the motor, as these are crucial components. Take your time with this step, as overlooking small issues can lead to bigger problems later on.

Once you're satisfied with the static inspection, proceed with a dynamic test. Start the bike and listen carefully for any unusual noises. Observe the bike's behavior as you slowly increase the speed. Take note of any strange vibrations, unexpected movements, or unusual resistance. Ensure the bike can start, stop, and change speeds smoothly and safely.

If you encounter any issues, refer to the troubleshooting steps below:

• Battery Issues: If your battery isn't holding a charge or is draining too quickly, check the connections first. Ensure the wires are securely attached and there is no damage to the wiring. If the connections are fine, the battery itself may be faulty and require replacement.
• Motor Problems: If the motor isn't engaging or is making unusual noises, check the wiring and connections to the motor. Ensure the throttle is functioning correctly and properly calibrated. If the motor still doesn't work, there may be an internal fault, and you should consider seeking professional assistance.
• Brake Issues: Brakes are critical for your safety. If you're having trouble with braking, check the brake cables, pads, and calipers for any damage or misalignment. Ensure the brake levers are properly adjusted and that the brakes are responsive and effective. If not, you may need to replace the brake components or seek professional help.
• Speed Controller Malfunctions: If your speed controller isn't functioning correctly, check the wiring and connections first. Ensure the controller is receiving power and that the throttle is properly connected and calibrated. If issues persist, the controller may be faulty and require replacement.

Remember to document your troubleshooting process, as it can help you identify patterns and find solutions more efficiently. Always exercise caution when testing and riding your electric bike, and make sure to comply with local laws and regulations regarding electric vehicles.

Frequently asked questions