How to turn a simple bicycle into an electric bicycle. What types of electric motors are there for bicycles and how to install them. do-it-yourself motor? Preparing the tools

For $100 you can’t even buy a regular bicycle, let alone an electric bicycle. 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 cutter 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 an oxy-acetylene cutting machine 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 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 (at maximum speed the smallest sprocket is used, and at minimum speed the largest is used) 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.

There are two ways to convert your bike to electric. Purchased parts undoubtedly look more impressive, and the layout will be so dense that visually any changes in the design will be almost invisible. And yet, making an electric bicycle with your own hands provides many advantages, including in terms of its maintainability. The main thing is to understand what scrap materials can be used and how to assemble it correctly.

Selecting components for an electric bicycle

Engine

Judging by the reviews on the forums, most home craftsmen are quite satisfied with the motor from a household washing machine of about 350 - 400 W. By the way, many industrial electric bicycles, for example, Wellness HUSKY (price around 51,000 rubles), are equipped with just such engines. The main thing is to choose the right type of electric motor. The commutator motor works equally well on both AC and DC power.

The pursuit of increasing power is a futile endeavor. The only advantage is that the traction force will increase when the electric bike moves uphill, but the speed is unlikely to increase significantly.

By the way, on the Internet there are homemade products based on a screwdriver. This experience should not be adopted - it is hopeless. Anyone who knows what kind of household power tool this is has already figured it out. Yes, and the price of batteries for it “bites”, and the service life with such use is 2 seasons, no more.

Battery

Before choosing a battery, you should decide what exactly the electric bike is for. For long trips, the battery capacity must be appropriate. How to proceed? Combine several into a battery or choose one, but with a larger charge? In the first case, installation becomes more complicated, since all elements will have to not only be fastened, but also connected into a single power supply circuit. Secondly, there is a significant increase in the dimensions of the battery. Therefore, finding a place for it will not be easy at all. But from the point of view of convenience of completing an electric bicycle, this option is preferable.

According to those who have already assembled an electric bicycle with their own hands, optimal battery parameters – 48 V (20 A/h, at least). The engine (380 W) is selected for it. It is quite enough to provide a speed of up to 40 km/h on rough terrain. The charge will last for a couple of hours. In terms of battery type, Ni-MH batteries are considered the best. In relation to an electric bicycle, its main advantages are large capacity and increased service life. And the price is quite reasonable.

If basically an electric bicycle can be assembled from scrap materials, then you should buy a battery. A 5,000 mAh product will allow you to travel up to 10 km without recharging at a speed of 20 km/h. When driving around the city (for example, to work and back) it is quite enough.

Transmission type

If the motor is from a household appliance, then there is already a pulley on the shaft. Therefore, it is a belt drive. This is the simplest solution, since all that remains is to install an analogue on the wheel (of course, the rear one). You can replace the pulley with a ring gear. The 52T series sprocket fits perfectly. It will turn out something like this.

Charger

You should also worry about this in advance. If the battery is selected, then it is not difficult to purchase the appropriate model that matches the parameters.

Features of assembling an electric bicycle

Any model of bicycle can be taken as a basis, so it makes no sense to describe the procedure in the form of step-by-step instructions. But it’s worth paying attention to certain nuances of making an electric bicycle with your own hands. Everything that is left unsaid will be clearly demonstrated by the illustrations.

• If the frame is metal, then most fasteners can be made by welding. With an aluminum or carbon version of the case it is more difficult. You will have to drill holes and use nuts and bolts to secure the components of the circuit.
• To make an emergency stop, the e-bike engine will have to be turned off. It is more convenient to locate the electrical circuit breaker in the brake handle.
• The optimal place for the “ignition switch” is the headlight. If necessary, you can also place a signal button in it, although this is unnecessary for an electric bicycle. Given the low speed, it will be possible to warn a pedestrian using your voice. And it is hardly advisable to complicate the circuit, since the sound signal is one of the consumers of electricity. But the battery capacity is not unlimited.

How can you equip an electric bike?

Those who understand electrical and radio engineering are trying to make the model more advanced. But it won’t be possible to assemble it only from scrap materials - you will have to purchase something, which means spending money.

• Wattmeter. It will show exactly how much distance you can still expect, taking into account energy consumption. This will allow you to change plans and adjust your route if necessary. It is advisable to place the device on the steering wheel so that it is always in line of sight.
• Controller. There are several options for such devices. The simplest thing, serving only as a terminal box, is attached anywhere. But many of them are assembled, for example, on microcircuits. Regardless of the chosen solution, it must be taken into account that all radio components require effective cooling. And this is understandable - electric current passing through the circuit is partially converted into thermal energy (due to the internal resistance of its elements). This means that it is advisable to place the controller on the frame so that it is better blown by the oncoming flow. Some of the paint in this area needs to be removed, and an additional aluminum plate must be placed, the bottom of which (at the point of contact) is covered with thermal paste.

In our world, full of a variety of machines and automated mechanisms, bicycles stubbornly do not lose popularity. They are remade, modernized, and new models of incredible shapes and sizes are created. But they are based on the same two wheels. And today we propose to turn a regular bicycle into an electric bike.
Such models are widely discussed on the Internet. The controversy surrounding them does not subside, because alterations sometimes cost more than cars. But the author of the video did not strive for glamor or stunning design. Quite the contrary, his electric bike model can be called a budget one. All parts can be purchased on Chinese sites or in domestic online stores. The bike itself is not overloaded, and thanks to the modification it looks quite modern. It can be made in an ordinary home workshop. Is it worth it and is it worth the trouble to come up with a “bicycle” again? Let’s find out together.

Materials:

• Regular bicycle;
• . You can, of course, take a DC motor and control it using;
• Lead-acid battery GP1272 F2 – 2 pcs;
• Metal plate (preferably stainless steel or aluminum);
• Aerosol car paint;
• Bolts, screws, nuts, washers;
• Wiring with terminals for connecting contact groups;
• Insulating tape;
• Tight anodized tension spring;
• Powerful loop with small shelves;
• Metal plates for clamps and gaskets;
• A section of profile pipe 15x15 mm, length - about 50 cm;
• Double tape.

Tools:

• Drill or screwdriver;
• Bulgarian (angle grinder);
• Welding inverter;
• Drills, cutting and grinding discs for grinders;
• Set of open-end and hex keys;
• Stripper for crimping terminals on wires;
• Screwdriver, pliers, paint knife and tape measure with pencil.

Assembling an electric bike

The author used a ready-made kit for converting a skateboard into an electric board as the basis for the driving mechanism of his electric bicycle. It can be bought on Chinese sites complete with an engine and a belt drive for around $100. They have a 24-volt motor that operates without brushes. For such devices, this is the most advantageous design, weight is about 500 grams, and power is 1800 W! Of course, with such characteristics, it has enough traction to easily pull the bicycle along with the rider.

Step one - making an electric drive on the suspension

First of all, we attach the mounting platform for the engine and the belt drive to the suspension axis. Next, we attach the skateboard wheel with gear to the suspension axle.

Now you need to correctly align the mounting platform for the engine. We turn it perpendicular to the vertical axis of the suspension, and tighten the clamping bolt with a hex key.

We install the engine on the seat, tighten it with four screws and put on a small gear for the belt drive.

Step two - connect the electrical circuit

The suspension assembly is ready, now it can be connected through the speed controller to the batteries. We connect them in series. The author of the video added a rheostat switch to the circuit in order to be able to smoothly change the voltage and monitor the operation of the engine at the same time.

We disconnect the rheostat (we won't need it anymore), and connect the radio-controlled controller-handle with a receiver-transmitter. This equipment is used by skateboarders to control electric boards. A convenient trigger on the handle will allow you to operate such a device easily and naturally.

Step three - attach the driving module to the bicycle frame

Installing such a module has its own characteristics. If it is fixed tightly to the bicycle frame, the skate wheel can rub the bicycle tire, and the engine can overheat from excessive stress and burn out. In a free position, such a suspension will dangle like unnecessary ballast while driving, especially on country roads. For a functional fastener, you need a fulcrum and a lever mechanism that will press the skateboard wheel to the tire. This is what we will do now.
We raise the rear fender of the bicycle higher to place the driving module in its place.

The suspension needs to be trimmed down slightly by removing the unclaimed second axle. We clamp the device in a vice, and use an angle grinder to cut it off flush with the mounting platform for the board. Clean the cut edges with a sanding disc.

We cut out a protective cover for the driving module from a sheet of metal. We mark it according to the size of the device and cut it with a grinder. To secure the engine, we make holes for the mounting plate and place it on the bolts.

The movable module will be attached to the frame using a small but powerful hinge. This will be the axis of our device. We secure the loop on the back of the protective cover with a welding inverter. We clean the seams with a grinder.

Using a piece of a regular door hinge, we make a clamp for fastening to the frame. We spray paint the protective cover with the hinge in the color of the bicycle frame. We fasten it with bolts to the moving module device.

We mount the entire device using a powerful bolt. We drill a hole in the hinge and frame, tighten the bolted connection through it with an open-end and spanner wrenches. You need to adjust its position in such a way that the skateboard wheel is aligned parallel to the slope of the wheel and moves in the same plane with it.

Step four - preparing the lever

The clamping mechanism is made in the form of a small lever. It rests on a rigid spring, defined for compression.
We attach a bolt to the cover that will restrain the movement of the spring and prevent it from jumping off.

We make the lever from a 15x15 mm profile pipe. We mark an angular cut at one end, and a 90-degree bend at the other. We make cuts with a grinder and weld the joint with a welder.

We make a crimp clamp from an aluminum plate to secure the lever to the frame. After cleaning the seams, you can start painting.

Step five - install electrics on the bike

We place battery banks on the diagonal cross member of the frame. We rest them against a vertical stand and wrap them tightly with tape, leaving only the contact terminals open. We install the lever on the frame, fasten the clamp to the bolted connection, and tighten it with a screwdriver. We put the spring in its seat and check the pressing force against the tire.

It will be very difficult for every person to pedal when going uphill, especially with a long incline. It is no less tiring to ride a bicycle against a strong wind, when even from a descent you need to apply force on the pedals so as not to stop. On straight sections of roads, and especially on slopes, a bicycle has some advantages: quiet operation, no restrictions on fuel reserves, and no state transport registration requirements. Most likely, if electric bicycles were widely available, then twice as many people would use light two-wheeled transport.

Electric bicycle device

To assemble a homemade electric drive or install a purchased kit on a bicycle, you need to know the purpose of the individual parts being installed. In essence, an electric bicycle is a regular bicycle, on which the following parts are additionally attached:

• electric motor;
• transmission mechanism;
• accumulator battery;
• controller;
• speed controller;
• control equipment.

The electric motor can be commutator, with brushes, or brushless, simpler in design, but larger in size with equal power. It is rational to install electric motors on a bicycle with a power in the range of 150-1500 W. Based on operating voltage, electric motors are selected for 12, 24, 36, 48 V. The higher the voltage, the lower the current flowing through the motor windings and connected wires, therefore, conductors of a smaller cross-section can be used.

You can assemble a belt, chain or friction transmission mechanism with your own hands.

The battery is usually mounted on the rack or in a mount on the bicycle frame. It is better to use maintenance-free batteries without liquid. Lead-acid batteries weigh more than other types of batteries for the same capacity. In addition, acid leaks out of them when the bicycle is tilted. It is wise to install a battery with a capacity of no more than 20 Ah, since larger batteries will be too heavy to carry on a bicycle.

The factory-assembled controller is a rectangular block in an aluminum case for better cooling. The main purpose of the controller is to change the amount of current supplied to the electric motor based on the voltage drop across the variable resistance in the speed controller. The current is regulated by power thyristors or field-effect transistors, which is why they need cooling during operation. Secondary functions of the electronic unit: measure the battery charge level, limit the battery charge current, limit the speed of movement on the bicycle.

The speed controller is actually a variable resistor. For convenience, this rheostat is installed in the usual rotary knob, which is placed on the steering wheel.

Control equipment includes:

• circuit breakers;
• brake lever with microcontact that turns off the electric motor during braking;
• headlight in housing, with power switch, signal, LED indicator of battery charge level;
• a sensor that turns on the engine when you pedal.

Types of electric drives

Electric drives for bicycles come in three types:

1. Frictional.
2. Chain, belt.
3. Motor-wheel.

Friction transmission

A similar type of electric drive is found on sale, but is not very popular. The drive assembly with electric motor and battery is mounted on the seat post, above the rear wheel. The transmission of rotation from the electric motor occurs due to the friction of the rubberized roller on the tire. It seems that in such a transfer everything is simple and reliable. But this transmission method works great only on children's electric cars and bicycles, and for daily use on a large bicycle it is not suitable.

Friction transmission has many disadvantages.

• The tire of the driven wheel wears out quickly.
• It is necessary to maintain increased pressure in the chamber of the moving wheel.
• The drive roller slips when climbing a hill or transporting cargo, especially when driving on a wet road or snow.
• A heavy drive creates a strong bending force on the seatpost and gradually breaks the bike frame.

A friction electric drive for a bicycle has one advantage - ease of installation.. It is within the power of every person to equip a bicycle with such a drive: just secure the device above the wheel, install the adjuster handle, and you can hit the road.

Belt or chain electric drive

Many craftsmen assemble this type of drive with their own hands from electric motors from washing machines, car starters, V-belts, chains, and heavy lead-acid batteries.

Electric drives with chain drives have disadvantages.

• An open gear is subject to increased wear.
• This transmission to the wheel is much noisier than that of other electric bicycle drives. The noise of a chain and belt is especially audible when walking a bicycle in a park or forest.
• To connect such an electric drive to a bicycle, it is necessary to place a bulky structure on the frame to mount the electric motor and the drive sprocket or pulley.

Electric drive via a chain or belt is very convenient to build a homemade electric bike.

1. You can connect a chain drive to a multi-speed bicycle transmission. By changing gears, it is easy to adjust the amount of force on the electric motor when climbing uphill, driving through deep sand and snow. When the electric motor rotates at full speed, does not hum, it consumes less current. The battery charge lasts for a long time if you do not overload the electric motor.
2. It is possible to assemble an electric bicycle with a chain or belt drive that can reach higher speeds than ready-made, factory-assembled options. The existing high-speed chain drive will help you achieve record speed on your bike.
3. Free choice of installation location for the electric motor, since the length of the chain and belt drive can be changed within a wide range.

We sell ready-made kits with sprockets, a chain, an electric motor, a battery, a charger, a controller, and a knob-adjuster that are suitable for a bicycle without shock absorbers, with a hardtail and full suspension. Only prices for electric sets with chain drive are higher than for sets of electric drives of other types. Kits with chain drive from the Taiwanese manufacturer Cyclone are very popular among buyers.

Motor-wheel

The most common type of electric drive available on the market. In such a device, a brushless electric motor is installed in the wheel hub.

A wheel with an electric motor has many advantages:

• It is not difficult to install the wheel motor, both on the back of the frame and on the front of the fork.
• You can assemble an all-wheel drive bicycle by installing two wheel motors.
• The running brushless motor is almost inaudible.
• A bicycle wheel with a large hub looks much better than an electric motor mounted on the frame.

There are several comments on the experience of using the wheel motor.

1. You cannot install a wheel with a high-power electric motor on an aluminum fork, otherwise the tangential rotational force of the motor will break the fork dropout antenna. The bicycle fork perfectly withstands lateral forces directed from bottom to top. The rear dropouts of the bike are designed for tangential force, which moves the wheel perpendicular to the axis, so you can safely install a wheel with an electric motor of maximum power on them.
2. You cannot spin a wheel motor with shorted wires coming out of it. The first thing a person does when he picks up a wheel is to start spinning it. When forced to rotate, any electric motor produces electric current. Three thick wires come out from the motor stator and two or more thin ones from the sensor. If these wires are shorted to each other when the wheel rotates, a spark will break between them and damage the sensor.
3. The electric wheel must be mounted so that the wires coming out of its hub are on the left. Then the wheel will rotate in the right direction.
4. In many Asian countries, there is a speed limit for cycling - no more than 25 km/h. Therefore, the controller provides a lock against exceeding the set speed. You won’t be able to accelerate faster, even by accelerating the bike with pedals. When the controller is turned off, the electric motor will operate in generation mode, like an electromagnetic brake.

Many kits are sold, which include: an assembled wheel with an electric motor from 200 to 1000 W, a controller, a battery, a charger, control equipment, and a speed controller. You can buy a cheaper motor-wheel kit for a bicycle, which does not have a battery, and sells not the assembled wheel, but the hub with the motor separately. The most popular electric bicycle wheels are produced by the following companies: Electra, Golden motor, Polariss, Yamasaki.

It must be said that now there is no point in assembling an electric bicycle from available components, since you can purchase a proven, reliable electric drive kit for a bicycle. In addition, you can buy a ready-made, beautifully assembled electric bicycle, for example, from the following manufacturers: GRACE, Izip, Sanyo Electric, Schwinn, Yamaha.

In the conditions of modern development of megacities, when personal vehicles for moving along the streets become burdensome, various types of two- and three-wheeled vehicles are becoming increasingly popular. In the West, special bicycle traffic zones are being created, bicycle parking areas are being organized, and numerous rental points for bicycles, mopeds and electric bikes have been opened. In Russia, many fans of two-wheeled transport are thinking about switching to an electric bike, but they are puzzling themselves with a number of questions:

• how to assemble an electric bicycle with your own hands,
• where to get the components and necessary parts for modifying an industrially manufactured “great”;
• How much will the modernization cost?

Of course, you can also purchase a ready-made model of an electric bicycle. Recently, various electric bicycles have appeared on sale, costing from 56.0 thousand (Volteco Freego model - South Korea) to 175.0 thousand (Dahon Ciao Ei7 model - USA) rubles. To select the best model, you need to study a large market with numerous models of bicycles, or you should trust the opinion of experts and choose one of them.

However, there are many skilled DIYers who find upgrading a regular road bike to an electric bike a lot of fun.

A brief excursion into history

The idea of ​​using an electric motor to drive a bicycle has been in the minds of inventors for a long time. The main obstacle to the implementation of this idea was the lack of rechargeable batteries, which, with sufficient electrical capacity, voltage and current supplied to the load, had insignificant overall dimensions and weight.

The impetus for the intensification of work on the creation of electric bicycles was the widespread use of lithium-ion and lithium-polymer alkaline batteries, which, despite their small size and weight, have high electrical characteristics and a service life that allows them to repeat charge-discharge cycles for a long time without losing quality parameters. Today, various types of these rechargeable batteries are widely used in cordless power tools.

Chinese manufacturers were the first to master not only mass production of electric bicycles, but also began producing a wide range of components, spare parts and accessories that allow you to turn an ordinary bike into an electric bicycle.

Peculiarities

Today, in the conditions of urban transport collapse, an electric bicycle is interesting due to its significant advantages over other types of two-wheeled transport, and environmental safety is not the least important. Functionally, an electric bicycle is similar to a conventional moped, in which the gasoline internal combustion engine is replaced by an electric power unit. The power of the electric motor of industrially produced models ranges from 0.25...1.2 kilowatts, while the electric bicycle is capable of reaching speeds of up to 50.0 kilometers per hour. The main advantages of an electric bicycle are:

• two methods of movement - using a conventional pedal drive and an electric motor;
• the ability to travel long distances using electric propulsion;
• compared to a moped and scooter, less labor intensive maintenance and better maintainability;
• environmental friendliness of the vehicle, thanks to which in the West owners of electric bicycles receive various benefits.

However, an electric bicycle also has certain disadvantages, the main of which are:

• high total weight of the power unit, including an electric motor, battery, additional transmission and control system (electric controller);
• long charging time of modern batteries, with their insufficient autonomy;
• high price of factory components;
• low speed of movement on suburban highways.

Selection of components for conversion

Having decided to convert his bike into an electric bicycle, the owner must take a responsible approach to the selection of components, paying special attention to the compliance (adequacy) of all elements of the electric drive. By saving on the purchase of a battery, you can get an electric bicycle, on which you can ride to the nearest supermarket without recharging, and return back by pedaling. Conversely, an electric motor that is too low-power will not only not allow you to develop the desired speed, but due to its low dynamics it will lose a lot of safety.

To convert a road (city) bicycle into an electric bike, you cannot do without:

You can take the path of least resistance and buy a wheel motor (“MAGIC PIE-3 26”, 17.5 thousand rubles) or a complete electric drive (“BAFANG BBS-01”, 45.5 thousand rubles), which will minimize complexity and labor intensity bicycle conversion.

If you purchase the engine, battery and control unit separately, you will additionally need:

• pulleys (2 or 4 units) from a passenger car electric generator;
• driving alternator belts;
• additional sprocket - it is better to purchase a kit with a “Bafang 52 T” mount;
• freewheel (ratchet, reverse clutch), which is necessary to transmit torque from the engine to the propulsion unit.

What should the frame be like?

The easiest way to install an electric drive is on a regular road bike with a steel frame. It is not advisable to use frames made of carbon fiber and aluminum alloys for electric bicycles.

A controller is mounted on the frame, which should be mounted on an aluminum plate that serves as an additional heat sink/radiator.

Installation of mechanics and engine

Installation of an electric drive on a future electric bicycle depends on the layout of the power unit, and it is easiest to assemble an electric bicycle with a traditional layout - the drive is carried out on the rear wheel. It is necessary to fix the “Bafang 52 T” sprocket on its bushing
, which will require the cyclist to have certain metalworking skills and the presence of a grinder with a diamond wheel and an electric drill. The sprocket disk is fastened to the bushing using four to six bolted connections, which must be secured with locknuts.

The chain drive to the rear wheel is carried out from a freewheel, which is installed separately on an intermediate support.
Rotation from the electric motor to the freewheel occurs through a belt drive assembled from generator pulleys and passenger car belts.
This complicated scheme for transmitting torque from the engine to the wheel allows one to avoid sudden jerks when starting from a stop, and also eliminates the reverse transmission of rotation in the direction of the wheel - the electric motor shaft.

The standard derailleur on the bike is used as a drive chain tensioner.

During the assembly of individual parts and subassemblies, fitting operations are usually required, which are performed using a conventional set of files of various sections.

Installation of electrical equipment

After assembling the mechanical part of the electric bicycle, installing and mounting the engine, battery and controller, it is necessary to assemble the electrical circuit.
Usually this operation does not cause any difficulties, and its complexity depends on the selected components. Particular attention must be paid to the reliability of contact connections, eliminating their sparking and heating.

It is advisable to additionally install an electric signal, which will increase traffic safety, as well as provide power to the headlight and backlight of the bike from the main battery.
Many enthusiasts install LED lighting on their wheels, which increases driving safety at night.

Conclusion

As can be seen from the description, if a cyclist has excess financial resources, free time and certain skills as a mechanic and electrician, converting a bicycle into an electric bike is not difficult. The only thing I would like to warn you about is...