Every year, the maintenance of personal vehicles in the city is becoming more expensive. Because of this, many city dwellers prefer to switch to a bicycle for the summer period. As a vehicle for commuting or long walks in the countryside, this vehicle is ideal.
Unfortunately, the infrastructure conditions of our cities and other settlements are far from ideal: often there are not only banal bike paths, but even decent public roads. And therefore, if you want to use a two-wheeled friend to travel to work and not only, you often have to deal with the fact that by the beginning of the working day you arrive tired and lathered.
Oddly enough, but you can make your trips much easier by putting a powerful and compact electric motor on your equipment. Today we will design an electric bike with our own hands. With the appropriate equipment and time, this is more thanreal.
A bit of history
If you remember, in the recent past it was difficult to imagine a sufficiently compact and light battery that could provide the movement of something heavier than a children's toy car within a hundred meters.
Movement in this direction began only after the widespread introduction of Ni-MH (nickel-metal hydride batteries), in which potassium hydroxide was used as an electrolyte.
It turned out that such batteries are able to store many times more energy than standard acid cells, and their service life is much longer. In addition, with the improvement of production technology, it quickly became clear that their cost is not so high.
At about the same time, many "homemade" people began to visit the idea of how they could make an electric bike with their own hands. And then a miracle happened: the ubiquitous Chinese began to produce on an industrial scale not only batteries, but also all other parts and mechanisms with which you can quickly turn an ordinary bicycle into a kind of electric "meteor".
Components and their cost
Of course, first of all we need an engine, which can be bought in foreign stores for about two thousand rubles. Next, you will have to purchase its controller, which costs approximately a thousand rubles.
Don't forget about a battery pack (also about a couple of thousand), as well as a servo tester and a quality chargerdevice. Together they will "pull out" again for a couple of thousand rubles. As for the battery, it is better to buy a product with a minimum of 5000 mAh.
In addition, there are all sorts of little things like power wires, connectors and a wattmeter, which you can buy at any store for electricians. Their price varies depending on the manufacturer, so it is difficult to give any specific numbers here.
Other accessories
But it's too early to relax! Before you make an electric bike, you should buy four pulleys from the VAZ 2108 generator, as well as a couple of generator belts from it.
In the cycling store you will have to get a freewheel, a couple of bushings and the highest quality chain. Don't forget the derailleur and 52T sprocket. Among other things, you will need a diamond blade for angle grinders, screws, nuts and clamps, which are best purchased with some margin.
Thus, everything will take at least 12-13 thousand rubles. If possible, it is better to purchase the highest quality components, but in this case, the cost of the project may increase significantly.
Mechanics
We start making an electric bike with our own hands with its mechanical component. Needless to say, all work must be done with the highest quality, as your own safety depends on it.
Assume your car will be equipped with traditional rear wheel drive. To ensure proper torque, we just need a 52T sprocket. Toattach it to the sleeve, you will need a diamond blade from an angle grinder with a diameter of 15 cm.
We bore the hole for the bushing with a drill and a file, relying on our own strength. You can fix this entire structure using standard "lambs" of a suitable size. Of course, you should think about balancing, otherwise you will experience extremely thrills at speed.
By the way, did you wonder why we bought the freewheel? The answer is: this is one of the most important design elements, as it prevents the transfer of torque from the wheel to the engine, which can lead to unpleasant consequences.
Please note that standard chains (you have an ordinary road builder, right?) do not sit on it, so the teeth will have to be slightly turned. To fix it to a 10 mm transfer hub, you will have to buy an adapter in a bike shop or go in search of a normal turner. By the way, without it, it will be difficult to make an electric bike with your own hands.
We use a standard speed switch to create the desired tension of the chain going from the freewheel to the driven sprocket. Strengthen the structure as much as possible, as the success of the trip depends on its strength.
Important! Torque from the engine must be transmitted in stages to avoid deformation and destruction of the sprocket, which in a conventional bicycle is simply not designed for such loads. Just for this, those pulleys and alternator belts from the VAZ 2108 that we bought earlier are used.
A littleabout frame
It was no coincidence that we mentioned that in the light of the design we are considering, it is preferable to use conventional road bike models. Since the engine power can be quite decent, we strongly do not recommend using carbon and aluminum frames. Ordinary steel, which is widely used in the manufacture of "ashanbikes", is best suited.
Electrical & Electronics
Having de alt with the mechanical part, we move on to the "heart" of our two-wheeled friend. Let's look at how to mount the motor for an electric bike and other important details.
Let's start with the controller. It is better to fasten it to the frame, and in this area it is advisable to scrape off the paint a little and put an aluminum plate smeared with thermal paste. This will allow you not to think about cooling it, which is very important during summer rides.
We care about safety
The servo tester should be switched to manual mode: it will be useful for setting the optimal motor power. To power it, it is recommended to use the L7805 chip. In order for the bike to give out all the possible power if necessary, we recommend placing a simple reed switch somewhere on the handlebar (in a convenient and easily accessible place).
In order to avoid sharp jerks in such cases, which are fraught with a breakdown of the teeth on the sprocket, we recommend putting a voltage divider on a pair of resistors connected to a 100 uF capacitor (ideally) at the input of the servo tester. So you canprovide a smooth increase in speed for about 0.5-0.7 seconds.
The wattmeter is best placed on the crossbar of the steering wheel, which will allow you to quickly track the consumption of electricity, ahead of time to make changes to your route. The batteries themselves for electric bikes will be optimally carried in saddle bags. So you can quickly change them to fresher ones, and access, if necessary, repairs will be greatly simplified.
Don't forget that your vehicle can accelerate to a decent speed. Based on this, be sure to provide at least the simplest sound signal that will warn other road users ahead of time about your approach.
Don't do this
On the Internet, you can find the statement that a do-it-yourself electric bike from a screwdriver will save you from purchasing all of the above components. It's not.
Let's see: even a 600 W screwdriver without intensive pedaling will not climb every hill, and even if you look at the wear of its mechanism … In addition, a mechanism of suitable strength will cost very, very expensive, even if you do not take into account the cost of branded batteries.
In a word, it is better to spend money on something more useful.
Some operating notes
Before you make an electric bike with your own hands, it is best to save a lot of money for powerful batteries. At the very beginning of the article, we talked about5000 mAh battery. It will be enough for about 8-10 kilometers, subject to rare accelerations up to 40 km / h. In this case, the average speed of movement should be about 18 km / h, which is quite decent and enough for comfortable movement around the city.
Here's how to build your own electric bike!
