Every year, the maintenance of personal vehicles in the city is becoming more expensive. Because of this, many citizens in the summer prefer to go on a bicycle. As a means of traveling to work or taking 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 decent public roads. And therefore, if you want to use a two-wheeled friend to travel to work and not only often have to face the fact that by the beginning of the working day you arrive tired and jerky.
Oddly enough, but you can pretty much ease the conditions of your trips 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 to do this is more than realistic.
A bit of history
If you remember, in the recent past it was difficult to imagine a fairly compact and lightweight battery that could provide the movement of something heavier than a children's toy car within a hundred meters.
Advances in this direction began only after the widespread introduction of Ni-MH (nickel-metal hydride batteries), in which potassium hydroxide was used as the electrolyte.
It turned out that such batteries can accumulate 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 was not so high.
Around the same time, many "homemade" and began to visit the thought of how to make an electric bike with their own hands. And then a miracle happened: the ubiquitous Chinese began on an industrial scale to produce 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 you can buy in foreign stores for about two thousand rubles. Next, you will have to purchase its controller, the cost of which is approximately a thousand rubles.
Do not forget about the battery pack (also about a couple of thousand), as well as a servo tester and a quality charger. Together they “stretch” again a couple of thousand rubles. As for the battery, it is better to buy a product at 5000 mAh minimum.
In addition, there are all sorts of little things like power wires, connectors and a power meter, which you can buy in any store for electricians. Their price varies depending on the manufacturer, so it’s difficult to give any specific figures here.
Other accessories
But it’s too early to relax! Before making 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 store for cyclists to get freewheel, a pair of bushes and the highest quality chain. Don't forget about the gear shift 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, no less than 12-13 thousand rubles will be spent on everything. If there is such an opportunity, it is better to purchase the highest quality components, but in this case the project cost can increase significantly.
Mechanics
We begin to make an electric bike with our own hands with its mechanical component. Needless to say, all the work must be done as efficiently as possible, as your own safety depends on it.
Suppose your car is equipped with a traditional rear-wheel drive. To ensure proper torque, the 52T sprocket is just what we need. To attach it to the sleeve, you will need a diamond blade from a angle grinder with a diameter of 15 cm.
We bore a hole for the sleeve with a drill and a file, relying on our own forces. You can fix this whole structure using standard “lamb” of a suitable size. Of course, you should think about balancing, otherwise, at a speed you will experience extremely thrills.
By the way, you didn’t wonder about why we bought freewill? We answer: this is one of the most important structural elements, as it prevents the transmission of torque from the wheel to the engine, which can lead to unpleasant consequences.
Keep in mind that standard chains (do you have an ordinary road builder?) Do not sit on it, so the teeth will have to be slightly turned. To fix it to the transfer sleeve with a diameter of 10 mm, you will have to buy an adapter in the bike shop or go in search of a normal turner. By the way, without it, an electric bike with your own hands will be difficult to do in principle.
We use the standard speed switch to create the desired chain tension going from the freewheel to the driven sprocket. Strengthen the structure as much as possible, since 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 normal bicycle is simply not designed for such loads. Just for this, they use the pulleys and generator belts from the VAZ 2108 that we bought earlier.
A little bit about the frame
It was not by chance that we mentioned that in the light of the construction under consideration, it is preferable to use ordinary road bike models. Since the engine power can be very decent, we strongly do not recommend the use of carbon and aluminum frames. Ordinary steel, which is widely used in the manufacture of ashanbikes, is best suited.
Electrics and Electronics
Having dealt with the mechanical part, we turn to the "heart" of our two-wheeled friend. Consider how to mount an electric bike motor and other important details.
Let's start with the controller. It is better to fix 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 grease. This will allow you not to think about its cooling, which is very important during the summer pokatushek.
We care about security!
The servo tester should be switched to manual mode: it is useful for setting the optimal engine power. To power it, it is recommended to use the L7805 chip. In order for the bike to give out all possible power if necessary, we recommend placing the simplest reed switch somewhere on the handlebar (in a convenient and easily accessible place).
So that in such cases there are no sharp jerks that can lead to tooth breakage on the sprocket, we recommend that you put a voltage divider on the pair of resistors coupled to a 100 μF capacitor (ideally) at the input of the servo tester. So you can ensure a smooth increase in speed for about 0.5-0.7 seconds.
It is best to put a wattmeter on the steering wheel cross, which will allow you to quickly monitor power consumption, ahead of time to make changes to your route. The batteries themselves for e-bikes themselves will be optimally carried in saddlebags. So you can quickly change them to more recent ones, and access to repair if necessary will be greatly simplified.
Do not forget that your vehicle can accelerate to a decent speed. Based on this, be sure to provide at least the simplest sound signal, which ahead of time will warn other road users about your approach.
Do not do that!
On the Internet, one can come across the assertion that an electric bike with your own hands from a screwdriver will save you from acquiring all of the above components. This is not true.
Let's see: even a 600 W screwdriver without the intense help of pedals will not climb every slide, and even if you look at the wear of its mechanism ... In addition, a mechanism that is suitable in strength will cost very, very expensive, even if you do not take into account the cost of branded batteries .
In a word, it’s 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 more money on powerful batteries. At the very beginning of the article, we talked about a 5000 mAh battery. It will be enough for about 8-10 kilometers, subject to rare accelerations up to 40 km / h. The average speed at the same time should be about 18 km / h, which is quite decent and enough for comfortable movement around the city.
Here's how to build an electric bike with your own hands!