The idea of installing an electric drive on a bicycle suggests itself. In fact, why is it possible to use an internal combustion engine (this has been practiced for a very long time), but not to use an electric one? With the modern level of electronics, such a modernization of a bicycle should be even simpler than using other engines. In addition, this will not require coordination with the registration services of the traffic police.
For those for whom this transport is the main means of transportation (for example, for daily trips to and from work), the electrification of the “two-wheeled friend” will allow significantly save your energy and nerves. There is no need to stand idle in traffic jams that are common nowadays; the speed of an electric bicycle is decent for urban conditions, so the actual travel time is often even reduced compared to conventional ground personal or public transport.
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By constantly recharging the batteries, at home or in any accessible place, you can have a significant range of mileage, and, with the correct calculation of the route and battery capacity, you can always be confident in your capabilities. Yes, in the end, in case of unforeseen troubles, you can get there in the usual way - on pedals.
Currently, you can, without much difficulty, purchase a ready-made bicycle with an electric drive, but its cost is quite high. Is it possible to re-equip your faithful “horse” yourself? It turns out that this is quite real, and many masters share their secrets online.
Some of them carry out a deep “upgrade” of bicycles, using completely unexpected design ideas, components and materials, often purchased at a flea market or in car dealerships. Less “advanced” ones simply purchase ready-made kits for the electrification of bicycle transport - fortunately, manufacturers offer them in a fairly wide range.
What types of transmission of rotational motion are there from the engine to the drive wheel?
Friction transmission
This type of electric drive, although found on sale, is not particularly popular. Its principle is simple. The engine is installed directly at the drive wheel, torque is transmitted directly from the stator shaft to the tire. It would seem that everything is simple and obvious. But what may be applicable for children's electric cars and bicycles is of little use in the actual use of transport.
Judge for yourself:
- There are no transmission links, that is, the possibility of increasing the angular speed of the wheel through the use of gearboxes is excluded;
- Extremely low efficiency;
- Even a slight drop in pressure in the wheel chamber will dramatically reduce the efficiency of such a drive.
- Constant friction between the engine clutch and the tire tread dramatically reduces its durability.
- In conditions of wet weather, dirty roads, frost, the friction coefficient will decrease significantly, the clutch will slip, which will reduce the already low energy output of the drive.
The only advantage of this system is its ease of installation, which does not require any major modifications to the bicycle.
No, if you are planning a modification with real improvements in the performance of the bicycle, it is better to immediately abandon such a scheme.
Classic chain or belt drive
This principle is most often used by DIYers because of its visual clarity and the wide selection of necessary components from ordinary bicycles. Electric motors from household appliances (for example, a washing machine) or automotive electrical equipment are often used as a motor.
What can we say about shortcomings similar drive?
- It should be immediately noted that modifying a bicycle in this way will require the owner to have sufficiently deep knowledge of mechanics and high technological skills.
- Another drawback is the noise of a system with this type of transmission, but in road conditions this is unlikely to cause significant inconvenience to anyone.
- The modification involves some changes in the frame design, which may reduce its strength characteristics. In any case, it is not recommended to carry out such work on bicycles with carbon or aluminum frames - only on steel ones.
But the shortcomings are brightened up by a number of benefits:
It is clear that there is a wide field for creative design ideas here. However, manufacturers have not forgotten about cyclists - there are ready-made kits for electric bicycles on sale. The most popular sets are from the Taiwanese company “Cyclone”.
Similar “constructors” are produced in different designs - using a standard bicycle chain, or with force transmission through an additional chain with one or two additional sprockets.
Systems are equipped with electric motors power from 360 to 1500 W, with a supply voltage of 24 or 36 volts. To control the operation of the drive, they are used electronic controllers, and in engines up to 500 watts they are usually built-in. The kit includes all the necessary fasteners, visual inspection and manual control of the drive.
Installing an electric drive will be a completely feasible task for any owner with “properly growing hands.”
The overall weight of the bike is quite acceptable - 3-4 kilograms, but the speeds it can reach are very impressive - 40 kilometers per hour or more.
The simplest solution is a wheel motor
For lovers of lightweight cycling, manufacturers offer another option, in which the electric motor and wheel are structurally arranged into one unit, the so-called motor-wheel.
Advantages such a system are obvious:
- When installing this drive, the bicycle does not undergo any significant modifications, and its appearance does not change significantly. The only thing is the installation of controls on the steering wheel and the battery compartment on the frame.
- Installation does not require any significant knowledge and skills - with the correct selection of the wheel-motor, it is probably accessible to everyone.
- The engine operation is almost silent.
- If desired, the bike can easily be transformed back into a regular one.
There are, of course, a number shortcomings:
- The wheel with the drive located in it is a fairly heavy structure (6 or more kilograms), increasing the total weight of the vehicle. Experienced cyclists recommend installing a reinforced front fork.
- There are certain restrictions on drive power.
- Exceeding the speed set by the manufacturer can have the opposite effect - the engine turns into a generator and spontaneously slows down the movement.
The kits sold are a brushless electric motor assembled in the wheel hub with a power from 200 to 1000 W.
As a rule, ready-made designs - with spokes and a wheel rim - go on sale, but for those who like to approach the matter in detail, simple engines are also sold. In this case, the selection and installation of the necessary spokes and rim falls on the owners of the vehicle. So to speak, a do-it-yourself motor-wheel.
The kit necessarily includes a controller that ensures proper operation of the drive, control mechanisms, and batteries with a charging unit.
Depending on your preferences, you can choose either a front or rear drive wheel. Some cyclists solve the problem “in one fell swoop” - making their “car” all-wheel drive.
Wheel motors are considered the most popular among fans of electric drives. "Polariss", "Yamasaki", "Electra", "Golden motor". You can purchase them both through specialized stores and by ordering online.
Realistically assessing your need for an electric bicycle, your financial solvency and technical readiness to perform manual installation, you can make a choice in favor of one model or another.
Video
Today we will tell you whether it is possible to make an electric bicycle in 30 minutes. The popularity of this safe, compact and lightweight type of transport is constantly growing. There is nothing complicated in the algorithm described below. We will pay special attention to the option of creating a folding structure. This product will last for many years if you follow safety precautions.
Advantages
Experts say that if you use a ready-made kit for an electric bicycle, assembly in 30 minutes is quite possible, just be smart. Such a vehicle has many advantages. It allows you to conveniently move around the city, which has a lot of traffic jams. No rights are required for such a tool.
In this case, there is also no need for fuel; only recharging the electrical controller is sufficient. This solution helps keep its owner fit, as it uses muscle strength.
It should also be noted that you can make an electric bicycle at home, with your own hands, thereby not depending on market prices and stores. The average unit can reach 42 km per hour. Weight will be about 35 kg.
We make transport
Assembling an electric bicycle in 30 minutes is a reality even for a schoolchild. But before you start assembling the model, you should decide what the result should look like and what specific tasks will be assigned to this transport. You can purchase a special kit for assembling an electric bicycle. This approach will greatly simplify all the work.
However, the most necessary element is the unit itself, which must have a thick frame. We have to install an electric motor on it. You can find the necessary components and parts in technical markets, in special stores for inventors, and at sales.
Main Components
We'll need a 48 volt motor and a bike that can handle it. In addition, a number of fasteners and tools will be used. And also resourcefulness.
Additionally you will need:
- motor mounts, made of stainless steel;
- fuses;
- switches;
- “asterisk” with 66 and 13 teeth;
- moped chain;
- rotary disc brake (2 pieces);
- acid batteries to start the power system;
- a special controller equipped with programmable control.
Next, modifications are made to the brakes and wheel fork. You can assemble an electric bicycle with your own hands in 30 minutes, but you should start with the front fork. After this we install the motor, battery, resistor. Craftsmen prefer to make a folding bicycle.
In a matter of seconds, such a vehicle can turn into a cargo version or fit in the trunk. The collapsible version can be considered more convenient in many ways, for example, ease of transportation in an elevator and reduced wheel size. The essence of the modification can be reduced to cutting the frame.
The connecting nodes should be welded to it in two places. They are secured using special bolts, screws and wing nuts. The unit disassembly procedure takes from one to two minutes.
Engine selection
If you decide to assemble an electric bicycle with your own hands in 30 minutes, you should remember that such a product requires an appropriate technical add-on. This will ease muscle effort. The engine is the main structural element. It should be selected according to the required current and voltage.
In this case, the power should be about 400 watts, in which case it will be possible to reach a speed of 30 km per hour, subject to the presence of a gearbox. The travel range is also within thirty kilometers. However, the latter indicator depends on the battery power.
Before choosing a model, you should consider the balance between battery capacity and voltage, as well as the corresponding engine performance. Let's look at this dependence with an example. If you use a 12-volt, 500-watt motor, you need a battery that has a capacity of forty amperes per hour. The permissible indicator can be calculated using Ohm's law.
If the discharge level is good, the battery can last longer. To save energy, it is advisable to accelerate with muscular force, while you need to stand on the pedals. This approach will save energy by a factor of 1.2. It is better to use up the charge while traveling on more difficult sections of the road. For example, the path may pass through a dirt road, slides and hills.
Resistor setting
To assemble an electric bicycle with your own hands in 30 minutes, you should take care of special gas handles. The variable resistor option makes it possible to control the number of engine revolutions and speed changes. It is necessary to first calculate the AC power, and then use the appropriate device with the required voltage.
Opening contacts are installed on the brake handle. Their position is always closed and allows electricity to flow through the circuit. Pressing the contacts closes and opens the circuit - the engine speeds up or stops. A standard kit usually contains the parts necessary for assembly.
The master’s task is to assemble them in such a way that the engine stops when you press the brake handle. To do this, use two aluminum pieces. We install one on the moving elements of the brakes, and the second on those that are at rest.
By welding, we connect this combination to the open circuit in the engine. For this we use brackets. This solution will provide the design with a functional electric brake.
Finishing touch
To design an electric bicycle with your own hands in 30 minutes, you will need knowledge of several laws of physics. For example, the electrical conductivity of various substances and the resistance of materials. Ohm's law will also come in handy.
With proper design, you can see in advance the gaps in the design being created, as well as determine the causes of possible problems or opportunities for subsequent modification. The structure of an electric bicycle includes the following elements: body, battery, variable resistor, motor.
Many people like bicycles for their comfort and the ability to exercise. They are used as a means of transportation in urban areas with difficult traffic. But not everyone wants to spend energy to reach the desired location.
Often the speed of a conventional device is not enough. Then ideas are born on how to create an electric bicycle from available materials so that it meets the requirements of environmental friendliness and is more functional. The fact is that purchasing a factory version is not affordable for everyone.
What are its advantages?
First of all, it is considered a mobile device for movement, since it can pass through the narrowest places of the road. And he is not afraid of traffic jams of varying complexity.
Let's consider all the advantages:
- Will be an excellent alternative to using public transport;
- An electric bicycle can be operated without the need to obtain a license;
- It does not need gasoline, however, the electrical voltage controller will have to be charged frequently;
- Helps you maintain physical fitness.
To decide that you need this type of transport, pay attention to the photos of homemade electric bicycles of various configurations.
They may differ in design features and functional characteristics: weight, available speed, driving range on a single charge.
How to create one yourself?
First of all, let’s figure out what you need to assemble an electric bicycle yourself. It is very important to find a functional bike that can withstand heavy loads. A lightweight model will not work - it must be a strong specimen.
But the most important thing is to purchase an engine with sufficient power. In addition, you will need the following list of additional elements:
- Controller based programmability;
- Two mechanical disc brakes;
- Acid type batteries;
- Set of fuses and switches;
- “Star” based on 66 and 123 teeth;
- Stainless steel fasteners for secure engine installation.
But this is not enough, because without the necessary tools it is difficult to secure all the parts.
How to collect?
Step-by-step assembly of an electric bicycle with your own hands is carried out. It is necessary to modify the brakes and the front fork, then move on to the rear. After this, the following are connected to the bicycle: the engine, the battery and the resistor - this happens in turn.
The diagram of the simplest finished model should include:
- Reliable body from the regular version of the bike;
- Efficient engine;
- Power supply;
- Battery;
- Correct version of variable resistor;
- A chain similar to a moped version.
You can create many different circuits based on the same battery. But speed and functionality may vary. To correctly create a reliable option, you need to have knowledge from the field of physics. We are talking about Ohm's law, the possibilities of electrical conductivity of materials and strength of materials.
But the regular version is simple and easy to create yourself. During the assembly process, you can notice some shortcomings and eliminate them or identify a way to modify the electric bicycle.
Engine
When thinking about how to make an electric bicycle yourself, everyone comes to one thing - you need a reliable engine. In order for it to work efficiently, it is necessary to ensure that the voltage and current match.
If the model has a power of 400 W, then, taking into account a reliable gearbox, you can reach a speed of about 30 km/h. And, if you install a capacious battery, then the range can reach 30 kilometers.
Important: Do not forget about the balance between the battery capacity and its voltage, the capacity and voltage of the unit. For an engine with a power of 500 W, you will have to install a 12 V battery with 40 amperes/hour. In other words, rely on Ohm’s law and then the electric bicycle circuit will last longer.
Pay attention! 
What controller is needed and how to set the resistor?
The controller changes the traction level of the electric bike. And this is what primarily distinguishes it from the regular version. This device helps to optimally distribute traction to all wheels and ensure smooth operation of the unit.
For this version, throttle grips are required. Using a variable resistor, it is easy to regulate the speed and speed of the engine.
After calculating the required energy level, the opening contacts are mounted on the brake handle (in closed form). By pressing the contacts, the circuit will open or close, and the motor will slow down or speed up accordingly.
Conclusion
Now you have simple instructions on how to assemble an electric bicycle yourself. It remains to advise not to overstress the battery by increasing the maximum speed of the unit.
Keep your bike away from direct sunlight as the battery capacity will noticeably decrease due to overheating. We recommend accelerating with your muscles to save precious energy.
Photos of electric bicycles with your own hands
Pay attention! 
Pay attention! 
For $100 you can’t even buy a regular bike, let alone an electric bike. But for this money you can make an electric bicycle with your own hands. Of course, you will have to get most of the necessary components for free! But where can you find them, and even for free, you say? I will tell you where you can find everything you need, as well as some points related to the differences between your components and mine.
This is a very difficult project - if you do not have good skills, then you should immediately abandon the idea of assembling an electric bike yourself and in a shop. If you know how to work with a lathe and have a good command of common tools, then you are quite capable of assembling an electric bicycle with your own hands. If you work only in your free time, then it will only take you a few months to assemble an electric bicycle.
Background and theory.
Before going directly to the instructions for assembling an electric bicycle, I will tell you why I decided to assemble an electric bicycle myself. I was able to design a friction transmission for an electric bicycle, while experiments with a chain transmission failed. But I really wanted to finish the job and find where the mistakes were made during the first attempt. It turned out that I did not pay enough attention to the tolerances. I almost randomly aligned and welded the sprockets into place where the shaft should be. That's why the transfer didn't work. In addition, since the motor shaft was very small, the transmission would not have worked even with a sprocket. So I had to find a way to get the transmission between the motor and the rear wheel using a standard rear cassette. As a solution, I chose a belt drive. But I still wanted to somehow change the belt drive to a chain drive on the rear wheel. A difficult solution could be a transmission shaft that would be mounted on the carriage and accurately combine the driving and driven stars. This option would have required me to weld the sprockets for a long time, so I abandoned it in favor of a much neater fastening technique. In addition, the maximum speed of my first electric bike left much to be desired - it did not exceed 32 km/h. Therefore, I had to recalculate the gear ratio and install a drive on the bike that allows it to reach a maximum speed of 64 km/h!
Precision is key to this project - all components need to be installed within very tight tolerances. Therefore, a lathe was required, without which it is not possible to ensure the required accuracy. This project cannot be completed without it.
So, let's get to work - we have to turn a regular bicycle into a powerful electric bicycle. And best of all, it will cost us less than $100!
Step 1: Necessary tools and materials.
This stage is very important. If you do not have the tools or materials listed below, I would advise you not to undertake this project.
Basic tools:
- lathe (required);
- welding machine;
- basic hand tools (hacksaw, pliers, etc.);
- caliper (be sure to buy one and preferably a larger one);
- drilling machine with a set of drills;
- tool for ;
- ratchet removal wrench;
- grinding machine;
- metal-cutting tools (hydraulic Piranha shears, but a plasma cutting machine or oxygen-acetylene cutting machine is also suitable);
- basic .
Additional tools:
- V-block;
- surface grinding machine;
- cutter;
- taps and dies.
Materials (except the obvious):
- iron corner;
- *ANSI #40 9T sprocket (available online from McMaster-Carr, item number 6793k208)
- 2 bearings (available online from McMaster-Carr, size listed below);
- round steel blank (diameter 0.5" - 1");
- 4" V-belt pulley (available online from Chicago Die Casting);
- a pulley for a V-belt with a diameter of 1" (I made it on a machine, but it’s easier to buy);
- V-belt.
*Dimensions depend on your bike and required top speed.
Step 2: Necessary kit for converting a regular bicycle into an electric bicycle.
This is probably the most important point. To ensure that the cost of converting a simple bicycle into an electric bicycle does not exceed one hundred dollars, you will have to get a free set of three main components: a motor, batteries and a bicycle.
Let's start with the bike. I think it won’t be difficult to find a bike that no one needs, or inexpensively. Try to get a bike with as many gears as possible - this will allow you to achieve a high top speed and improve acceleration. The presence of a gear shift system is also necessary because it will make it possible to increase the tolerances in the chain drive. Search on the Internet or ask your relatives in the village and perhaps you will be able to buy an unwanted bicycle in good condition for a nominal sum. Or maybe your own bike is too old and you have been wanting to exchange it for a new one for a long time. Or even, if all options have already been exhausted, then you can find a good bicycle among the scrap metal in a landfill. But if the bike has been on the street for a long time, then it will first need to be slightly repaired and adjusted. I think it won't be difficult to find a bike.
Next, we can kill two birds with one stone. It is unlikely that you will find an old chair with an electric motor, which I had. You can try searching online for an old motor and batteries, but your best bet is to go to a wheelchair repair center - you'll have a better chance of success. Service technicians have a lot of old batteries and motors that they simply throw away. I think that they will not refuse to sell inexpensively an electric motor and several 12-volt batteries from an old chair. Even if they don’t have anything, they will be able to tell you who else you can ask. As a last resort, you can ask your friends if they happen to have a motor or batteries lying around.
Step 3: Making the bearing outer ring.
I was lucky - my bike already had a threaded outer bearing race. If you're not so lucky, you'll have to make the bearing outer race yourself. You can do it without threads - secure it in the carriage with screws.
Step 4: Making the intermediate shaft.
Since your bike will most likely be different from mine, the parts you make will be different from mine, but the intermediate shaft should be essentially the same. If you bought a large roller, bearings and sprocket with a center hole diameter that is half the diameter of the sprocket, then you will need a steel blank with a diameter of 5/8 of the diameter of the sprocket. On a lathe, turn one end of the workpiece into a section 1" long and half the diameter of the sprocket. Then measure the distance between the two bearing rings and reduce it in diameter to 5/8 of the diameter of the sprocket. Turn the remaining section of the workpiece to a diameter half the diameter of the sprocket. An area in the center measuring 5/8 of the sprocket diameter is necessary to prevent the intermediate shaft from slipping backwards or forwards.
All that remains is to drill the holes for the bolts. First you need to secure the shaft using a V-block. It is very important that these holes are exactly in line. The size of the bolts depends on the shaft size you choose and the size of the other components.
Step 5: Sprocket modification.
If you have the same sprocket as me, then due to its large width it will not fit the bicycle chain. Therefore, the sprocket will have to be slightly modified. Turn it on a lathe with a scoring cutter to a width of 0.1 inch. Then set the cutting carriage to 10 degrees and change the angle of the teeth so that it is the same on both sides.
Step 6: Main Drive Pulley.
Since it is unlikely that you have the same motor as mine, I will simply describe the process of processing mine. Since my motor already had a hole, I drilled a one-inch diameter hole inside the round aluminum piece, which exactly fits the size of the shaft. It is extremely important that the hole size does not exceed the size of the shaft at all - otherwise you will have to redo this part of the job. Next, I drilled a hole and machined one end to 0.5 inches in diameter to match the roller I machined earlier. But it’s quite possible that nothing will need to be modified on your engine.
Step 7: Intermediate Shaft Assembly.
This is where the fun begins! Before you start assembling your bike, buy a set of roll pins and a set of screws from the store and start assembling! There may be some problems at this stage, but if you have turned everything correctly, then you will be able to connect everything correctly.
Step 8: Chain drive assembly.
At this stage you will have to use a tool to install the chain. Undo the chain to remove it from the bike. Now you need to install the chain as usual, thread it through the rear derailleur and hook it onto the middle sprocket on the cassette. Make sure the rear derailleur is in the correct riding position: not bunched up and in the correct gear. Next, place the two ends of the chain next to each other to obtain the required chain length. This is the most difficult moment. Disconnect the circuit at this point.
When disconnecting the circuit, make sure the pin is attached to the end of the circuit. If this is not done, it will be very difficult, if not impossible, to reconnect the circuit.
Step 9: First test without load.
Now you need to check the work done. What could be worse than when, after finishing assembling the electric bike during testing... the chain falls off. Therefore this is a very important test. Turn the bike upside down so the rear wheel can rotate freely. Set it to any gear, but I recommend setting it to the lowest. Now let's move on to the most difficult part. To ensure , hold the motor securely with one hand downwards against the V-belt. With your other hand, connect the motor with wires to the battery. And if you did everything correctly and accurately, the test will be completed successfully. If the chain does fall off, there could be many reasons for this. One of them may be that the intermediate shaft sprocket is too wide, so you will have to grind it down a little. If the belt slips, then you have set the gear too high or the drive belt is not tensioned enough. If the chain still falls off, it is most likely due to poorly aligned sprockets and unfortunately you will have to do some steps again.
Step 10: Motor Mount Layout.
Next you need to make a cardboard mock-up of the motor mount. Why cardboard? There are several reasons for this: cardboard is cheaper than metal, it can be cut with a knife, and it is much easier to shape than metal. If the design of your bike allows, then I would advise installing the engine behind, like mine. This will give you more room for the batteries and keep the motor and most rotating parts away from your feet.
Step 11: Pre-mount for the motor.
Next, using the created cardboard mockup, cut out the mount from a sheet of metal. Attach the cardboard model to a metal sheet of metal and trace it with chalk as carefully as possible. To cut a model out of metal, you can't do without a tool like the Piranha - large hydraulic shears designed for cutting metal. They allow you to cut a metal model very accurately and evenly along the contours. But most likely you don’t have this tool. Therefore, you can get by with a conventional plasma cutting device. However, when cutting a thick sheet of metal, quite a lot of slag is formed, and if you have poor knowledge of the plasma cutting technique, you will have to grind the edges for quite a long time. You can also use oxy-acetylene cutting or a hacksaw, but these two options are much worse.
Step 12: First stage of engine installation.
This is a key point when installing the engine. You'll need to cut holes for the bolts on the unequal angle (if you have one) and install the U-bolts so they can slide up and down the base plate. Since you already have a cardboard layout, marking it will be easy. Simply place the layout on the plate and mark the two ends of each slot with a center punch. Drill two holes at each end for a total of four holes. They should not be too large so that you can tighten the nut properly, and not too small so that you can push the bolt through. Since I used 3/8" diameter bolts, I drilled the holes at an optimal diameter of 0.4" in diameter.
Step 13: Second stage of engine installation.
Now you need to cut the slots. At first I thought about cutting them out with a router bit, but for some reason I decided against that option. If you have an end mill and a vise of the appropriate size, then you are still better off using a router bit. I chose plasma cutting. Using the angle iron as a guide, I cut straight slots for the bolts. The appearance of the slots was far from ideal, so I had to sand them long and hard. It is very important that the slots are as straight as possible. This is necessary so that the bolts slide smoothly and are securely fixed.
Step 14: Installing the unequal corner.
Depending on what engine you have, you may not need to do this step. I made an unequal angle to secure the motor, but I was unable to use it due to insufficient clearance between the rear tire and the angle. I still recommend, if possible, installing an unequal angle, as it provides additional strength for securing the engine. But if this is not possible, then simply use U-bolts instead of an angle.
The next thing you'll need is some sort of adapter bracket. It is attached to the engine and can slide up and down on the main mounting plate to provide the required belt tension. Make a plate that screws onto the front of the engine and hangs slightly to the side. Then take a small rectangle that runs parallel to the motor and bolt it to the main mounting plate.
Step 15: Welding the engine mount.
After a thorough sandblasting and a little wire brushing, you're ready to start welding! Also make sure that all joints, dirt, etc. Welding two metal sheets of different thicknesses is not going to be easy. Even if you burn a hole, it won't be the end of the world. Don't try to brew everything at once. First, weld one side, and a little later move to the other so that the metal has time to cool. In addition, try to direct most of the heat to the mounting plate and use the lowest possible welding temperature, which still allows the sheets to be boiled well. If necessary, you can even add additional molten metal to better solder the two sheets of metal. I even wanted to use metal arc welding, which is of high quality, but unfortunately I don’t know how to use it very well.
Step 16: Belt Drive Assembly.
This step does not require detailed explanation. Simply place the belt on both pulleys, pull it as tight as possible, and tighten all the bolts. As you use the bike, you will notice that the belt will gradually stretch. This is precisely the reason why we had to make an adjustable mount. You should check the belt tension from time to time and adjust it if necessary.
Step 17: Second test without load.
Let's re-test the bike without a load to make sure we've secured the engine and shift system properly. Set to the lowest gear and run the engine at maximum speed. If the mount holds well (it should), then begin to gradually increase gears. If the bike computer is installed on the rear wheel, then pay attention to its readings. If, then naturally it will not show anything. Also pay attention to whether the belt is slipping, which may indicate a poorly tensioned belt or a very high gear ratio.
Step 18: Attaching the Battery.
The next step is to install the battery. I hope you were able to get a good set of old batteries from a service center or just buy them. Check the functionality of the batteries and charger. Then make a cardboard mockup of the batteries. It is much easier to move an empty cardboard box than two 14 kg batteries. After this, select a suitable place to install them. It is advisable to install them as far from and as close to the ground as possible - this will increase traction on the rear wheel and lower the center of gravity of the bike.
Once you have found a suitable installation location, use iron corners to construct a “pallet” to which the batteries will be securely attached using zip ties or elastic cords. Then simply weld the "pan" to the . The quality of the weld must be very high, since it will have to withstand quite large loads. So try to weld the “pan” well.
Step 19: Electrical circuit diagram of the electric bike.
You probably have a question why we haven’t yet mentioned the electrical circuit for controlling the electric bicycle’s motor. Of course, we will not have full control with a pulse width modulation controller. Since the bike has a gear shift system, a regular switch is enough to control the engine. I installed a 10 Amp SPDT switch from an old radio. It has three working positions: on1, on2 and off. As can be seen from the diagram above, in on1 mode one battery with a voltage of 12 V operates, and in on2 mode two batteries with a voltage of 24 V operate. This allows you to turn on the motor at full speed or at half speed. By having two motor speeds and a gear shift system on the bike, we can provide a wide range of speeds, eliminating the need to purchase a very expensive PWM controller.
There is another version of the circuit - with three batteries. Each electrical circuit has its own advantages and disadvantages. The top picture shows the electrical circuit of an electric bike with three batteries, and the bottom picture with two batteries. I used the option with two batteries, which is what I would recommend using.
Step 20: First trip, troubleshooting.
This is the best stage of all! Now that you've finally finished assembling your electric bike, it's time to ride it. Call all your friends and show off your DIY electric bike. Don't forget to put it on, because if something goes wrong, and most likely it will, you don't want to get it. You must mentally prepare for failure - most likely your homemade electric bike will not work the first time. Many problems can happen, ranging from poor wire contact to incorrect calculation of the gear ratio. Before carrying out this test, be sure to stock up on various tools that will be needed to eliminate various possible malfunctions:
- Disconnecting wires
- Gear ratio too high
- Defective batteries
To diagnose this problem, lift the rear wheel and turn on your homemade electric bike. If the tire rotates, then most likely the gear ratio is too high. Try increasing the countershaft pulley or decreasing the engine pulley - this will reduce the gear ratio and increase torque, which will allow the bike to move. If the tire does not rotate, then either the wires are disconnected or the batteries are not working. Fully charge the batteries and check the voltage with a multimeter. The voltage on fully charged batteries should be approximately 26 - 27 V. In addition, use a multimeter to check the integrity of the electrical circuit. Disconnect the wires going to the motor and connect them to the multimeter. Turn on the switch. If the device displays only zeros, while the batteries showed voltage, then the problem lies in the wires or switch.
The bike is moving slowly:
- Wrong gear ratio
To diagnose this problem, lift the rear wheel. If it spins much faster than when you were driving, the gear ratio is too high and needs to be reduced. To do this, it is necessary to either increase the size of the intermediate shaft pulley or reduce the size of the engine pulley. If the tire rotates as quickly as it does with a load, then you instead need to increase the gear ratio either by reducing the size of the countershaft pulley or by increasing the size of the engine pulley.
Step 21: Additional improvements.
If you're willing to spend a little more and are willing to go beyond your hundred-dollar budget, you can optionally equip your e-bike with a speed controller. In my project it is not necessary, because the required speed range can be obtained solely through the gear shift system. However, a speed controller can definitely be useful. Very good controllers from Alltrax.
Step 22: Mathematical calculations.
When assembling a homemade bicycle, you will have to carry out a lot of mathematical calculations. I will give here a few formulas that I used.
((R((pi*A)/ (pi*B)))(C/D)(pi*E))*0.000946969697, where R is the number of engine revolutions per minute, A is the diameter of the engine pulley, B is the diameter of the countershaft pulley, C is the number of teeth on the countershaft sprocket, D is the number of teeth on the rear sprocket (the smallest sprocket is used at maximum speed, and the largest at minimum speed) and E is the diameter of the rear wheel.
Secondly, you need to calculate 5/8 of the length of the intermediate shaft. Considering that the outer surface of the bearing outer race is the largest dimension of the carriage, insert it and measure it with a caliper. I got 2.817 inches. Then remove the bearing outer race and place the bearing and race ring flat on a table or other hard surface. Then use a caliper to measure the distance from the inner edge of the bearing to the table. Take these measurements with both rings. I got 0.591 and 0.595.
Then add these two values and subtract this value from the largest dimension to get 5/8 of the countershaft length. I got 1.631".
Calculating the size of bearings is very simple. This requires absolutely no mathematical calculations. Just measure the inner size of the rings and buy a bearing that matches this size as closely as possible, as wide as possible and preferably with a central hole of 0.5". It is not necessary to buy bearings of this size - they can be machined with high precision to the desired size.
The popularity of such a compact, lightweight and safe form of transport as a folding electric bicycle is growing from year to year. How to make such a design with your own hands to save on purchases?
Advantages
Experts say that to make a fashionable and durable design, all you need is a little ingenuity, buy the appropriate parts - and your faithful electric horse is ready. It has many advantages:
- with such transport you can easily move around a city full of traffic jams;
- it does not require a driver's license;
- no need for fuel, just recharging for the electrical controller;
- it helps maintain athletic shape due to the muscular strength used;
- a homemade electric bicycle made with your own hands helps you to be independent of stores and market prices.
The average unit reaches speeds of up to 42 kilometers per hour, and at cruising speed it goes at 26 kilometers per hour.
The weight of the entire device will be up to 35 kilograms. To make a high-quality and reliable model from available materials, you should use the recommendations of experienced craftsmen.
We make wheeled vehicles ourselves
Where does the assembly of the entire model begin? First, we need to decide what the result should look like and what goals we want to achieve with the help of this transport. You can buy a special kit for an electric bicycle - it greatly simplifies the entire assembly work. But the most important thing that is needed is the unit itself with a thicker frame on which an electric motor can be installed.
You can find the necessary parts and components at sales, in stores for inventors, and in markets with technical goods. An advanced student can easily assemble an electric bicycle with his own hands in 30 minutes.
Main Components
Typically you need a 48-volt motor, a sturdy bike that can handle it, and some tools and mounts. As well as patience and resourcefulness, readiness for technical tests.
Additionally you will need:
- special controller with programmable control;
- acid batteries for the power system;
- disc brake (2 pcs.) rotor type, mechanical;
- moped chain;
- “asterisk” with 13 and 66 teeth;
- switches;
- fuses;
- stainless steel motor mounts.
Some craftsmen prefer to assemble a folding bicycle, which in seconds can turn from a regular one into a cargo bike or fit in the trunk. The collapsible version is convenient for many reasons - reduced wheel size, ease of transportation in an elevator.
The essence of the modification is to cut the frame, to which connecting units are welded in two places. They are fixed with special bolts, screws and the procedure for assembling and disassembling the unit at home takes less than 1-2 minutes.
Engine selection
A homemade electric bicycle requires the installation of an appropriate technical superstructure that will facilitate muscular efforts. The main element of the entire structure is the engine. It is selected according to the desired voltage and current. In this case, the resulting power should be around 400 watts, then it will be possible to reach speeds of up to 30 kilometers per hour if there is a gearbox. The travel range can also reach 30 kilometers, depending on the battery power.
Before choosing a model, it is important to consider the balance between the voltage and capacity of the battery and the voltage and capacity of the engine. For example, when choosing a 500-watt, 12-volt motor, you need a battery with a capacity of 40 amperes per hour. The permissible capacity is calculated according to Ohm's law. At a normal level of discharge, the battery will last longer and be more reliable. To save energy, it is better to accelerate with muscle power while standing on the pedals - this will save energy by a factor of 1.2. It is better to spend the charge on more difficult areas while moving: hills and slides, dirt roads.
Resistor setting
A three-wheeled adult electric bicycle or a two-wheeled one equally requires the presence of throttle handles. The variable resistor option helps control the speed change and the number of engine revolutions. Having calculated the AC power, take the appropriate device with the required voltage. Opening contacts are installed on the brake handle - their position is always closed, allowing electricity to pass through the circuit. Pressing the contacts opens and closes the circuit - the engine stops or accelerates.
Typically, a standard e-bike kit contains the necessary parts for assembly. The master's task is to make sure that the engine stops when pressure is applied to the brake handle. To do this, take two aluminum pieces. One is installed on the moving parts of the brakes, the second on the stationary parts. Connecting this combination to the open circuit of the motor, which is attached to the brackets by welding, provides a functional electric brake.
Scheme development
To assemble an electric bicycle with your own hands in 30 minutes, you need a minimum of skills, but knowledge of some laws of physics is required.
For example, Ohm's law, resistance of materials or electrical conductivity of various substances. By drawing up a simple diagram in accordance with classical technical requirements, you can clearly see gaps in the design, the causes of possible problems or opportunities for further modification.
The electric bicycle circuit includes the following elements:
- bicycle body;
- current source;
- engine;
- variable resistor for introducing an open circuit;
- battery.
Different schemes make it possible to improve the invention and accelerate vehicles to higher speeds using the same battery.
Choosing a controller
The main difference between a classic vehicle and an electrified one is the presence of a special control device. This is a controller for an electric bicycle, which is a box that manipulates the traction of the entire unit. If your country has a speed limit for cycling, this device will help you set the limit while riding. Most often it is 25 kilometers per hour.
The design of such a sensor does not include electric brushes.
But there is a processor that monitors the position of the wheel rim magnets. The controller allows you to optimally distribute the load on the wheels, reduce heat generation, and allow the engine to normalize the effort of moving without jerking.
Developed movement algorithms help you move evenly and at the same speed.
Operating rules
Today you can see with your own eyes quite a few vehicles assembled by craftsmen. They perform mountain climbs, dangerous stunts, and conquer gorges. But you can simply enjoy a good, reliable car that has received a second wind thanks to the engine.
It is important to follow the technology for making an electric bicycle with your own hands in 30 minutes, but you need to pay no less attention to the recommendations for the correct use of this vehicle.
You cannot constantly overstress the battery by exceeding the set speed in the engine. Also, the bike should not be placed in the sun - the battery may overheat and lose capacity by 80% of its original volume. Temperatures around 40-45 degrees are especially dangerous in hot countries.
You can assemble an electric bicycle with your own hands in 30 minutes with sufficient quality. It will last for many years if you follow safety precautions and correctly follow all recommendations.
So, we figured out how to make a homemade folding electric bike. As you can see, there is nothing complicated about this.
