Building A Speedy Electric Bike: A Diy Guide

Building a fast electric bike is an exciting project that can be undertaken by anyone with a get-your-hands-dirty spirit. It is a lot easier than one might think! All you need is a bike in good working order, a conversion kit, and a battery. Using a conversion kit makes the process super simple and fast. If you shop online to find the best deal on the kit and repurpose a bike you already own, this can be an inexpensive project. You can also add a pedal assist sensor, but if you plan on using the bike more like a light electric motorcycle, you can skip the pedal assist sensor and just use a throttle. Once you experience the thrill of a high-power mid-drive, you won't want to settle for less!

Choosing the right conversion kit

Electric bicycle conversion kits are a great way to add a boost to your current bike without the price tag of a full e-bike. These kits contain all the bolt-on parts needed to convert a standard bicycle into an e-bike. When choosing the right conversion kit, there are several factors to consider. Firstly, decide on your desired speed and power output. If you plan to reach speeds of 30 mph or higher, investing in a reputable kit with high-quality components is crucial for performance and safety. For example, the 4T version of a motor is faster than the 6T but comes at the cost of reduced torque. Additionally, ensure your kit includes safety features like torque arms, which are essential at higher power levels.

Another important consideration is the type of brakes your bike has. Disc brakes are recommended as they provide superior braking performance, which is crucial when dealing with the increased weight and speeds of an e-bike. The compatibility of the conversion kit with your bike's brakes and axle is vital, as some kits are specifically designed for bikes with front disc brakes and quick-release axles. Furthermore, the wheel size of the conversion kit should match your bike's wheel size to ensure a seamless installation.

When selecting a conversion kit, you may also want to consider the battery specifications. Some kits allow you to choose the battery size and shape, while others require you to source your own battery separately. It's important to understand the range that different battery capacities offer. For instance, a 10Ah battery typically provides a range of around 18 miles, while an 18Ah battery can offer up to 33 miles. Additionally, look for batteries with high-power cells that can handle the load without overheating.

While there are many affordable conversion kits available, it's worth investing in quality. Cheap alternatives may not offer the same performance, safety, or durability as more reputable options. However, if you're on a tight budget, Chinese manufacturer Bafang offers a range of conversion kits that provide a good balance between cost and quality. Their mid-drive and front hub motor kits offer flexibility in terms of wheel size, display preferences, and battery options.

Lastly, consider the level of support you may need during the installation process. Some kits, like the Swytch eBike Conversion Kit, offer excellent customer support, making them ideal for beginners or those unfamiliar with electric bike systems. Additionally, some kits may require you to send your bike to a specific location for professional installation, so be sure to factor in any additional costs and inconveniences.

Selecting a battery

Voltage

The voltage of the battery plays a significant role in the power output of your electric bike. A higher voltage battery will provide more power, resulting in higher speeds. For a fast electric bike, it is recommended to choose a battery with a voltage of 36 volts or 48 volts. The 48V Li-ion battery is a popular choice for those aiming for speeds of around 30 mph.

Capacity

The capacity of the battery, measured in ampere-hours (Ah), determines how long your electric bike can operate before needing to be recharged. The capacity you choose depends on the intended usage. If you plan to use your electric bike for short trips, a 10Ah battery will suffice. However, if you intend to take longer rides, opt for a higher capacity battery, such as a 20Ah, to ensure you have sufficient range.

Compatibility

It is essential to ensure that the battery you select is compatible with your conversion kit. The voltage and capacity of the battery should match the requirements of the kit. Check the specifications of the conversion kit to determine the compatible battery types.

Battery Type

There are different types of batteries available, such as lithium-ion (Li-ion) and lead-acid batteries. Li-ion batteries are commonly used in electric bikes due to their high power-to-weight ratio, compact size, and long lifespan. They are also known for their fast charging capabilities. Lead-acid batteries, on the other hand, are less expensive but heavier and have a shorter lifespan.

Safety

Safety is a critical consideration when selecting a battery. Choose a battery with high-quality cells that can handle high power without overheating. Additionally, look for safety features such as over-discharge protection and temperature control to prevent any potential hazards.

Ease of Installation and Replacement

Choose a battery designed specifically for electric bicycles, as they typically come with a charger and are easier to install. Consider the ease of removing and replacing the battery, especially if you plan to swap out batteries during longer rides.

When selecting a battery for your fast electric bike, it's important to balance power, range, and compatibility with safety and ease of use. Always follow local regulations and ensure your battery choice aligns with any legal requirements or restrictions.

Installing the motor

First, select a suitable motor for your project. The power of the motor will determine the speed of your electric bike. For example, a 1,000 W direct-drive kit can help you achieve speeds of up to 30 mph. If you're aiming for higher speeds, consider a more powerful motor like a 1,500 W kit from a reputable company like West Coast Electric Cycles.

Next, gather the necessary tools and safety equipment. You'll need items like wrenches, screwdrivers, and cable ties. It's important to wear protective gear, such as gloves and safety goggles, during the installation process. Before beginning the installation, carefully review the instructions provided with your motor kit. Each kit is unique, and familiarizing yourself with the specific steps and components will ensure a smoother process.

Now, you can begin the installation. Remove the bike's existing wheel, which is typically the rear wheel, and set it aside. If your bike has brakes attached to the wheel, carefully detach the brake cables as well. The motor kit will come with a new wheel that has the motor already attached. Carefully install this new wheel onto the bike frame, ensuring that it is securely fastened and aligned properly.

Once the motor wheel is in place, you'll need to connect the motor to the bike's battery. This typically involves running wires from the motor to the battery, ensuring they are securely attached and protected from potential damage. Use cable ties to neatly secure the wires to the bike frame.

Finally, test your setup. Connect the battery and turn on your electric bike. Start by slowly pedalling in a clear, paved area and test your brakes at a low speed. If everything seems to be functioning properly, you can gradually increase the speed and listen for any unusual sounds. Ensure you take the necessary safety precautions during this test ride, including wearing a helmet and checking local regulations for using electric bikes.

Adding the pedal assist sensor

There are two main types of pedal assist systems: basic PAS sensors and torque sensors. Basic PAS sensors are more affordable and detect the speed at which the cranks are turning. This type of sensor is ideal for those who wish to regulate motor power independently from their pedal effort. On the other hand, torque sensors detect how hard the rider is pushing on the pedals and are considered the gold standard for PAS control. This type of sensor is suitable for those who want a physical workout while riding their e-bike, as the motor is only activated when pressure is applied to the pedals.

If you opt for a basic PAS sensor, you can choose between two common types: a magnet ring attached to the crank arm or spindle with a sensor that detects passing magnets when the pedals are turned, or a speed sensor that detects forward pedal rotation or rotational speed to activate the motor.

For those who want the best of both worlds, some e-bikes offer both a pedal assist system and a throttle. This combination allows you to pedal when you want to help conserve battery power or get some exercise, and use the throttle when you need a boost or want to cruise without pedalling.

Testing and inspecting

Initial Testing

Before taking your electric bike out for a spin, conduct a thorough inspection and testing of all its components. Start by checking the tightness of all bolts, nuts, and screws. Ensure that the axle nuts on each wheel are tight and there is no wheel wobble. Inspect the electrical system, including all electrical connections and wiring, for any signs of damage or loose ends. Test the functionality of the throttle, speed switch, on/off switch, and other controls. Make sure the battery is securely attached and fully charged.

Test Ride

Choose a suitable testing location, preferably a clear and paved area, away from public roads if high-speed electric bikes are not legal in your region. Start by setting your speed selector switch to the lowest setting. Turn on your e-bike and begin by gently pedalling to get a feel for the bike. Gradually increase the speed and pay attention to the brakes, ensuring they respond effectively at different speeds. Listen for any unusual sounds, such as pinging or rubbing, which could indicate something rubbing against the wheel or spokes, such as loose wires or cable tie ends.

Post-Ride Inspection

After your test ride, conduct a comprehensive inspection of the bike, including the frame and components, for any signs of stress or damage. Check the tires for wear or damage and maintain proper tire pressure to ensure optimal performance and efficiency. Inspect the brake pads for wear and replace them if necessary. Additionally, check the chain, gears, and moving parts, and lubricate them regularly to prevent rust and ensure smooth operation.

Regular Maintenance

To keep your electric bike in top condition, develop a regular maintenance routine. This should include cleaning the bike with mild soap and water, avoiding high-pressure jets. Regularly inspect and tighten all bolts, nuts, and screws as they can loosen over time due to vibrations during rides. Check the suspension and steering for smooth operation, and ensure that the gear shifting is smooth, making adjustments as necessary. Finally, pay attention to battery care by avoiding complete depletion and recharging the battery after each ride. Store the battery securely, avoid extreme temperatures, and keep it in a cool, dry place when not in use for extended periods.

Frequently asked questions