Building An Electric Family Bike: A Step-By-Step Guide

Electric bikes are a great way to commute and can be a fun way to get more exercise with your family. Building your own electric family bike is a challenging project, but it can be done with some tinkering skills, a good set of tools, and a lot of problem-solving. You can save a lot of money by building your own, but it's important to do your research and be aware of the laws regarding e-bikes in your region. This introduction will cover the basics of how to build an electric family bike, including choosing the right conversion kit, batteries, and other materials.

Characteristics and Values Table for Building an Electric Family Bike

Electric bike conversion kits

There are various companies that offer electric bike conversion kits, such as eBikeling, E-BikeKit, and Dillenger. These kits are designed to fit most bike types, including mountain, road, hybrid, and commuter bikes. The kits typically include all the necessary parts for a DIY installation, such as a hub motor, controller, display, throttle, and sometimes even an LCD dashboard.

When choosing a kit, you will have the option to select different voltage and wattage configurations, such as 36V to 48V and 500W to 3000W. It is important to consider the power output that best suits your needs and preferences. Additionally, you will need to purchase batteries separately, as they are not always included in the kit. The cheapest and most compatible option for electric bike kits is typically a sealed lead-acid battery (SLA), which can be found online or at various retailers.

Installing an electric bike conversion kit can be a challenging task, and it is important to have strong problem-solving skills and some knowledge of machining tools. However, with dedication and the right resources, you can successfully convert your traditional bicycle into an electric one, opening up a world of new commuting possibilities.

Choosing a battery

Choosing the right battery for your electric family bike is essential to ensure a good riding experience and to save money in the long run. The battery is the biggest expenditure and the biggest ongoing expense in owning an electric bike. The cheapest option is a sealed lead-acid battery (SLA), which costs around $160 for four 12-volt batteries and lasts for about two years. However, there are less bulky options available on the market.

When choosing a battery, it is important to consider the amp hour rating, which tells you how much amperage a battery can provide in an hour. For example, a 10Ah battery can provide 1 amp of power for ten hours or 10 amps for one hour. You should also consider the voltage of the battery, which impacts the range you can get out of your electric bike. A higher voltage battery, such as a 52V battery, will provide a longer range than a lower voltage one, such as a 48V battery.

It is also important to choose a reputable manufacturer to ensure the quality and durability of the battery. Grade A cells from well-known manufacturers such as Samsung, LG, Panasonic, and Fujitsu are recommended. Samsung batteries are a popular choice for many electric bicycle brands due to their longer lifespan and higher capacity, and they are also more affordable in the long run. LG batteries are also a great choice due to their innovative technology, but they may be more expensive.

Additionally, you may want to consider the enclosure for the battery pack. The simplest method is to wrap the pack in plastic, such as shrink wrap, but this offers no protection from impact. A more typical enclosure is a plastic case, often called a "shark pack" or Hailong pack, which provides more protection for the battery.

Installing the kit

First, you will need to obtain a conversion kit and a battery. The cheapest option for a battery is a sealed lead-acid battery, or SLA, and the charger that comes with the kit is designed for this type of battery. The voltage and capacity of the battery you choose should be compatible with the conversion kit. A 36- or 48-volt battery will allow for speed and comfort, and the capacity of the battery defines how long it will last.

Next, you will need to remove the wheel that is being replaced. Open the rim or cantilever brake using the lever, and if the bike has disc brakes, remove the retaining or cotter pin or the clips or springs that hold the pads in place.

Then, you will set up the chain, ensuring that the rear derailleur is in the right position to ride and not bunched up or on the wrong gear. You will then break the chain in the link, ensuring that the links you break will mesh, and that the pin remains attached to the side of the chain.

Finally, you will install the batteries and the motor driver on a cargo bracket above the rear wheel of your bike, in a fabric carrying bag. The bracket is designed to fit with most standard bicycles at the clamp that fixes the seat height.

Wiring the battery

Choosing the Right Battery:

First, select a battery designed specifically for electric bicycles. These batteries come with a compatible charger and are generally easier to install. You can choose between a 36-volt or 48-volt battery, with the latter offering more power and speed. Additionally, consider the battery's capacity, opting for a 10Ah for shorter trips or a 20Ah for longer rides.

Sourcing Batteries:

Batteries can be expensive, so consider sourcing them from medical supply stores, as they often have access to old batteries and motors that they may be willing to give away. You can also try scrap yards or dumps for free or low-cost options. If you're on a tight budget, sealed lead-acid batteries (SLAs) are a more affordable option, but they are bulkier.

Battery Placement:

The batteries will be installed above the rear wheel on a cargo bracket, along with the motor driver. This placement ensures weight distribution and easy access for future battery changes.

Wiring Process:

Now, for the wiring process itself:

• Ensure you have a clear, well-lit workspace and lay out all the necessary tools and materials, including the battery, wiring harness, connectors, and any other components provided with your conversion kit.
• Refer to the instructions provided with your conversion kit. Different kits may have slight variations in the wiring process, so it's essential to follow the manufacturer's guidelines.
• Connect the battery to the wiring harness, ensuring correct polarity. Usually, the red wire is positive (+), and the black wire is negative (-).
• Secure all connections with the provided connectors or soldering, if specified in your kit's instructions.
• Route the wiring harness along the bike's frame, ensuring it is securely fastened and doesn't interfere with the moving parts of the bike, like the chain or wheels.
• Connect the wiring harness to the motor, again, ensuring correct polarity.
• Test the connections by engaging the throttle gently. The motor should respond accordingly, indicating successful wiring.

Remember, working with electricity can be dangerous, so always exercise caution and refer to expert guides or seek professional assistance if you're unsure about any part of the process.

Testing the bike

Initial Checks and Setup:

Before taking your electric family bike out for a ride, perform a thorough inspection and some initial tests. Check that all the components are securely installed and correctly connected, paying close attention to the wiring layout for safety and functionality. Ensure that the battery is adequately protected from vibration, shock, and moisture to prevent electrical issues like overcharging or short-circuiting. Verify that the display panel, lights, and other accessories are functioning correctly. Familiarize yourself with the bike's power-up sequence, ensuring that the motor engages smoothly.

Static Testing:

Conduct static tests to evaluate the performance and responsiveness of critical systems without actually riding the bike. Test the braking system to ensure it offers reliable and responsive stopping power. One method is to approach a set of cones and apply the brakes once the front wheel reaches the cones, aiming to stop as quickly as possible while maintaining control. Measure the stopping distance and repeat the test for each braking system and rotor size to compare their effectiveness.

Test Ride:

Find a suitable location for a test ride, preferably a safe, open space. Start pedaling and gradually build up your speed, experimenting with the different pedal-assist levels to understand their impact on your riding experience. Pay attention to the bike's acceleration, ease of direction change, and stability. Choose a route that includes flat surfaces and challenging terrain to comprehensively test the bike's performance.

Post-Ride Inspection:

After the test ride, conduct a post-ride inspection to ensure that all systems are still functioning correctly and there are no unusual noises or vibrations. Check the alignment of the motor to ensure it is parallel with the wheel, as misalignment can cause uneven wear and tear, reducing the motor's efficiency and lifespan.

Safety Certifications:

To enhance safety and regulatory compliance, consider obtaining safety certifications for your electric family bike, especially if it utilizes a lithium-ion battery. Organizations like UL Solutions offer fire safety certifications (UL 2849) that examine the electrical drive train, battery, and charger systems. This can provide peace of mind and also enhance the marketability of your custom electric family bike.

Remember, building and testing an electric family bike requires a good understanding of mechanics and electrical systems. Always prioritize safety and make any necessary adjustments or improvements based on your testing results before taking your bike out for regular use.

Frequently asked questions