Review of a Chinese manual charger for a mobile phone from an engineer. Homemade foot generator for mobile Homemade hand generator for charging your phone
Engineer Igor Beletsky presents a video review of a Chinese manual charger for a cell phone. Not long ago, a friend of his purchased a small charger for a mobile phone from a Chinese online store.
Judging by the number of videos on the Russian-language Internet, many have already acquired this “miracle device” and were happy to demonstrate its capabilities. Of course - compact, lightweight, and most importantly not expensive charging and only for a couple of bucks, plus free shipping. And what are the parameters declared by the seller! At a voltage of five and a half volts, the current can reach six hundred amperes! Wow! Well, who wouldn’t be tempted? The Chinese are great masters of playing around with ears. Although if you connect your phone to this charger and turn the handle, then very soon it will light up and indicate the start of charging. But it seems that few people have actually tried to charge something with this miracle. Otherwise there wouldn't be so many rave reviews. If you look at it, this charger produces good voltage. But the battery is charged not by voltage, but by current, which, alas, is not present here. The maximum that we managed to squeeze out was 50 mA. With this current you can charge your phone forever. The seller is silent about how many Chinese people need to be involved to get 600 mA.
Looking inside, the reason for such disgrace becomes clear. A conventional electric motor is used as a generator. Of course, it can be used as a cheap generator, which is quite Chinese, but with such a small size of the motor, its windings are made with such a thin wire that a larger current simply cannot flow through them. Unless, of course, you spin it at warp speed. After which it will simply overheat and burn out.
For normal operation of this device, all you had to do was install a motor three to four times larger. There are plenty of such electric motors on radio markets. After disassembling office equipment, they are sold “by weight”. It would not be so compact, but without deception. Any owner of a Chinese charger, if desired, can easily make such a replacement on his own. The design will suffer a little, but there will be results. Now it is quite possible to obtain a charge current within 0.5 A. It is doubtful that anyone will be able to use this charger for 2-3 hours to fully charge the phone, but for a short-term recharge for an urgent call it is quite suitable.
A normal conventional generator looks much more solid and costs 5-10 times more. They can be found in the Chinese online store. Can i .
Chinese sellers are cunning beasts. It cannot be said that the product reviewed in the video does not work at all. For example, even a large LED flashlight can be powered with such charging, because it does not require a large current to operate. But they will have to forget about charging their mobile phone.
Violating the speed limit in the city often leads to unjustified and tragic events. Therefore, in especially sensitive places, near busy intersections, schools, hospitals and public buildings, it is customary to install “speed bumps” that restrain the ardor of overzealous drivers. However, not for everyone... Read moreA wind generator needs wind, which does not blow constantly, and solar panels need sun, which does not come for weeks, especially in winter and in cloudy weather. Generators powered by internal combustion engines require fuel, which only becomes more expensive, making them unprofitable, as well as maintenance, etc., making them an expensive toy, or an emergency source for a short time.
I want to consider this option. For example, a manual generator that runs on human muscle power. Besides the fact that you have to turn it yourself, it has a number of advantages. It does not depend on weather conditions (wind, sun), it is also mobile, easy to handle, and can be used anywhere. The smallest representatives and the most famous are Chinese hand-held dynamo chargers for small electronics. But such small “dynamics” are only suitable for emergency charging, and using them for constant energy production is extremely inconvenient.
Firstly, they provide too little energy, and to charge a simple phone or small flashlight you need to turn them for hours. And if electricity is needed every day, then such devices, firstly, will not withstand and will quickly fail from constant loads, since they are made of plastic and are not designed for a long service life. And it’s simply not advisable for a person to twist this thing for several hours a day in order to charge a mobile phone and other electronics, and after 15 minutes of twisting, his hands simply get tired from monotonous movements.
The solution may be to have a larger manual generator, so that it produces a much larger current that can be used to charge a large battery. And this battery can be used to power and charge portable electronics. That is, a large generator can charge or recharge a capacious battery, which, for example, will be equipped with a car cigarette lighter socket. And after some time, use this energy by connecting various electronics through the cigarette lighter socket.
And when the battery runs out, charge it again. This solution will allow you to constantly use energy and at the same time turn the generator only when the buffer battery runs out of charge, and a large battery can last for weeks or more. It depends on how you use electricity. I think it is clear that such a source is considered only to provide the minimum human energy needs, such as charging portable electronics, and maximizing the use of a laptop.
For these purposes, for example, this ready-made option may be suitable. Military hand-held generators, they are precisely designed to generate electricity in any conditions and in any place. The power of such generators is from 3 watts to 70 watts. There are many models with different characteristics, and more modern analogues also have many outputs adapted not only for charging large batteries, but also for charging portable equipment (USB, 12V, 19V outputs)
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They can also be equipped with any necessary additional inputs and outputs. The advantage of such large generators in comparison with Chinese speakers is obvious. Such a generator is quite powerful and produces up to 100 watts of energy in a couple of hours, while small generators produce only 2-3 watts. This means that they can charge a large battery, for example, like on a computer UPS, and then use the energy.
But lead-acid batteries do not like fast charging and quickly fail. The optimal charge mode is about 10% of the battery capacity. What I mean is that you shouldn’t charge lead-acid batteries with increased current, but how can you reduce the charging time if the battery needs to be charged for 10 hours, because you can’t turn it that much.
There are two options here: use lithium-ion batteries, which can be charged with high currents, but now there are almost no high-capacity lithium-ion batteries on the market. Or NI-HM batteries of the new generation, which can be charged with high currents up to half the capacity of the batteries themselves. The only thing is to monitor the temperature of the batteries, as they get very hot at high charging currents. And you need to make sure that the temperature does not rise above 70 degrees Celsius. Or use large lead-acid batteries with a 10% charge capacity.
For example, if you take a military generator, as shown in the figure above, and spin it as written in the instructions, that is, 60 rpm, then, depending on the model, it will produce a nominal voltage, for example, 50 watts. It turns out that the generator will produce about 4A of current, which means that if you use a lead-acid battery for charging, then you need a capacity of about 40A. A car battery will do, but less is possible. If you use a small battery, you need to make sure that the current does not go beyond the design parameters. For example, for a 10-amp battery, the charging current is 1A, but for a short time it can be up to 2A.
If we consider something really powerful, like a high-power home or camping power station. You can also use a practically ready-made option, such as a bicycle and a bicycle motor-wheel. Now, with the development of electric transport, a large selection of kits for converting bicycles to electric power has appeared on sale.
A ready-made wheel motor is used as a motor. This wheel motor is also an excellent low-speed high-power generator. And it can produce, for example, a wheel motor with a power of 350 watts; in generator mode at the same speed it can produce up to 300 watts of energy. Below in the photo is an example of a finished power station based on a bicycle with a motor-wheel. 
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As the basis for such a power station, you can use either a ready-made bicycle or just a frame with pedals, which can be installed permanently. Also, a wheel motor is needed without any additional bicycle “principles”. And the generator itself is much cheaper than a bike conversion kit. Prices for motor wheels start at 3,500 rubles, but you can find cheaper ones, especially secondhand. All adaptation to a generator consists of connecting the motor as a generator.
The wheel motor is a three-phase low-speed permanent magnet motor that produces alternating voltage in generator mode. To rectify, convert current from alternating to direct, you need to make a simple rectifier using diodes. And also to monitor the battery charge you need to connect an ammeter and a voltmeter. Below is an approximate diagram of connecting the battery for charging.
When using control devices when charging, it is good to navigate. For example, when charging a car battery, you need to keep the current no higher than 6 amperes, although up to 10 amperes are possible for a short time. And the generator itself can output up to 20A. Using a voltmeter you can check the battery charge level. If the voltage at the terminals during charging rises above 14.5 volts, it means the battery has been recharged; you should also not lower the battery discharge below 11 volts, this also affects the resource.
In order not to charge a dead battery for 10 hours, you can do this. When the battery runs out a little, just recharge it, although this should be done more often, but in terms of time it will be much less, 1-2 hours. When using such a power station, you can charge portable electronics and connect LED lighting through the cigarette lighter socket in the absence of electricity. And when used economically, it is enough to spin such a shaft generator once a week, since in 1 hour you can generate up to 100 watts of energy.
Surely many of us, when we are busy at the table with something important and nervous, shake our legs under the table. This homemade author had just such a problem; to turn this problem into a benefit, he decided to build a generator, with the help of which he can now charge his mobile and other devices from his foot. The generator is a pedal that, when pressed, generates an electric current.
Let's look at how to assemble such a homemade product below.
Materials and tools for homemade work:
- expression pedal;
- 3D printer;
- stepper motor;
- PC Board;
- voltage regulator type LM7805;
- capacitor with a capacity of 1000 uF;
- a capacitor with a capacity of 10 uf and one capacitor of 0.1 uF;
- eight diodes type 1N4007;
- two 15K transistors;
- USB-A and USB-B extension cable;
- seven 1/2” spacers;
- seven 3/4" metal screws;
- nut and bolt M4X8 mm;
- four bolts with nuts M4X12 mm;
- four plastic dividers 1/4";
- four bolts with nuts M3 x 12 mm;
- wire to create a spring or spring;
- acrylic disk (made according to a template);
- felt disk (also made according to a template);
- glue gun.
Homemade manufacturing process:
Step one. Disassembling the pedal
First of all, you need to disassemble the expression pedal, to do this you need to unscrew a couple of screws. Inside you can find a potentiometer with a lever; this lever must be removed by pulling it. Then you can remove both potentiometers from the pedal; they will not be needed. There is a printed circuit board on the base plate; all the wires need to be cut off from it.
Step two. Working with a 3D printer
Now you will need to print a couple of parts on a 3D printer. The necessary files in STL format are included for download.
Step three. Engine Installation
The engine is mounted using a 12mm bracket using bolts and nuts. The motor itself is attached to the inside of the pedal in such a way that the lever on the shaft faces upward, that is, the way it was on the potentiometer.
Now you will need a drill and a 3/16 drill bit, using it you need to drill holes as guides. But here you need to be careful not to make a through hole in the paw pad. Well, then the engine is attached to the body using screws and 12 mm nuts.
Step four. Circuit design
Step five. Installing the lever
The motor shaft must be rotated so that when installing the lever on it, it faces up. As a result, when you press the pedal, the motor shaft will rotate.
Step six. Power circuit
The circuit for power regulation should be arranged as in the photo. It is made of two rectifier bridges, one bridge goes to each motor coil. To accumulate charge and filter noise, a 1000uF capacitor is used, then using the LM7805 generator, this energy is converted into the reliable 5 Volts necessary to charge the phone.
There are also 10uF and 0.1uF capacitors in the circuit; they work as additional filters in the generator.
It is also necessary to install two resistors; without them, the mobile phone may not be charged from such a power source.
Step seven. Cable installation
You need to take the USB cable and cut it into two parts, there will be a total of four wires in the cable. The cable must be connected to the printed circuit board as shown in the diagram.
Step eight. Spring installation
To install the spring you will need a drill and a 3/16 bit to make a hole in the center of the plastic contact pad of the expression pedal. Then an acrylic disk is installed in the upper part of the platform; for fastening, the author used an 8 mm bolt and nut.
Opposite the plastic pad there is a felt pad; you need to glue a felt disk onto it. After the glue has dried, you can install the spring in the pedal.
Step nine. Homemade assembly
Now all the elements need to be put together. First you need to solder the motor wires to the printed circuit board in accordance with the diagram.
To attach the printed circuit board, the author used a drill and screws with nuts. The whole thing is secured with four screws. Spacers will also be needed here.
Homemade manual generator for charging your phone
Welcome, dear friends, to our Video Teacher portal. You urgently need to make a call, but your phone battery is dead, and you find yourself in a place where there is no electricity nearby, watch the video lessons from the do-it-yourself section. In this video training, we wanted to present you with a video lesson on the topic “Homemade manual generator for charging your phone.”
Homemade manual generator, how to make it?
How to make a camping generator for charging a mobile phone using a hand trainer that is popular today. For the experiment we took an inexpensive plastic model. The structure of the simulator is very simple, two halves of the body and a rotor. The rotor is the most important and interesting part in this device; it can spin over 10,000 rpm. On the rotor, along its circumference, you need to install neodymium magnets. You can use the original rotor, but it would be better if you made it metal and more massive.
Now, for it to become a full-fledged electricity generator, you need to add a small inductor coil to it, literally 150-200 turns of 0.2 wire will be enough and it should be placed strictly above the flying magnets. To do this, we will fix it in the place where the cover is located, the cover of the hole where the meter is attached. To do this, I made a special metal plug with a core, where I place a small coil, leading the wires out through the side hole. These wires will need to be connected to a separate wire that you will connect to the load. Continue watching the video...
Watch video instructions for creating a homemade hand generator on the video training portal, Video Teacher. Enjoy watching and good luck to you!
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