The smartphone is dead and there is no outlet nearby? The situation is frequent - modern smartphones quickly sit down if you use them to the fullest. This is where portable charging comes in! But how to make the right choice so as not to be left without communication and entertainment? Let's show you what I chose and what problems I ran into in the end.
By tradition, first a little theory.
Now the most popular power source is a lithium battery. They are everywhere - in phones, cameras, laptops ... Even disposable electronic cigarettes have a rechargeable lithium battery.
The most common format for lithium is 18650 (18*650mm). Such "banks" are used in most laptop batteries.
Well, since laptops are one of the most popular products in the world, manufacturers are striving to improve this particular type of battery.
Which makes 18650 ideal for use in flashlights, e-cigarettes and portable chargers.
Lithium batteries have their drawbacks - they do not like to be discharged very much and deteriorate during uncontrolled charging. Therefore, in ordinary stores you will not find "bare" lithium batteries, they are built into devices or sold together with a charge / discharge controller. But no one bothers you to find your old laptop battery and pull the batteries out of it. Their condition may be far from ideal, but a freebie.
It would seem, what does it have to do with batteries from laptops, if portable chargers are sold ready-made and often non-separable? It is enough to type the cherished words in the search - and here they are, full of bright colors:
Let's brainstorm. The average buyer, of course, will never disassemble the charger and think about replacing the batteries. Therefore, the manufacturer can put anything in there - from Chinese low-quality batteries to the same used ones from laptops. But even if high-quality batteries are in the power bank, they are not eternal - a couple of years and in the trash. Therefore, the ability to replace the power supply is simply necessary, otherwise the device may turn out to be "disposable". Try to find a replacement battery like this:
I'm used to taking everything in China, and I recommend it to you - we can't find normal things for a reasonable price. More than two years have passed since my review, during which time I ordered dozens of Chinese goods, visited many sites. There were cases of fraud, there were also very long delivery times. Most liked for very fast delivery and many free shipping options. There I bought a few favorite chargers.
All of them can be replaced with a battery and, importantly, they are supplied “empty”, that is, batteries are purchased separately.
Familiar to all flashlight lovers, the ML-102 is very easy to use. It is enough to insert the battery and ... everything. There are no buttons or battery level indicators. I connected the phone via USB - the charge went, connected via microUSB to the PC - the battery itself started charging. Declared current limit - 1.2A
The blue LED shows the current USB current consumption. The brighter, the more voracious device is connected.
Red changes to green after the battery is fully charged
The internals are as simple as the charging itself:
We connect the consumer to 1A and see that charging is doing an excellent job:
When the battery is discharged, charging to the last tries to deliver the requested current, then it goes out:
My conclusion: the best charge at 1 * 18650. Extremely simple and therefore convenient. Due to the independence of the charge and conversion circuits, you can simultaneously charge it and connect something to it. But if you have a completely discharged smartphone, you won’t be able to “squeeze out the last juices” from charging - it won’t be able to give out the required current and will cut off.
Of the minuses - not designed for protected batteries. They just don’t fit in there, although some manage to stuff them into it by modifying the design with a knife and a file. There is no charge level indicator. It is constantly on and in standby mode (the blue diode is barely noticeable, but it glows).
This charger is already larger, it fits three batteries. Some versions also have a built-in flashlight (it shines really well). There is a button and a charge indicator. When in use, the indicator flashes red/green/yellow alternately, while charging the internal batteries, it flashes first red, then orange, then green, depending on the charge level. Declared current in 1A
Inside, everything is not very good - the LED does not have cooling, some parts are not soldered. In the photo, details from versions with and without a flashlight:
On the this moment, I don’t have such a charge on my hands, so you won’t see the tests.
In conclusion, I didn't really like it. Even in this device and three batteries, all three channels are independent! This is good in terms of the fact that the batteries will not affect each other, but it is bad that at the same time energy is taken from only one of them. If none is able to supply the requested current, the device turns off. Batteries connected in parallel could produce the required current by "common efforts".
What I like is that it is convenient to change batteries. Removed the cover, changed the battery and you're done. Made really convenient, there are special recesses for extraction. There is a lot of space, protected batteries are also placed, the springs are soft, they are inserted without difficulty.
Also, when using, the indicator just blinks. It is impossible to know the charge level without turning off the device to be charged. The power supply stops immediately after the cable is disconnected, there is no delay. Yes, and you can not turn off the charging during operation.
Also for three batteries, but not triangular, but flat. Instead of a three-color indicator, there are four blue LEDs. But there are already two USB ports, 1A and 2.1A. When used, the current charge level is displayed every 5 seconds. When charging, the charge level is also visible.
Everything is held on by screws, it is inconvenient to disassemble. And it’s also difficult to assemble, the springs strive to push out the plug:
It also copes with consumption of 1A (it also supports 2.1A, but I did not find anything that eats so much):
And it turns off in the same way if you connect a voracious device with a low charge level:
and then instantly cut off
The result is a good charge at 3 * 18650, maybe one of the best. Full metal body. The button is recessed to prevent accidental pressing. All batteries are in parallel, thereby increasing efficiency. Can deliver more current, therefore, has two USB port, one of which is 2.1 A. The indicators work both during use and when charging from the mains.
Of the minuses - it also cannot be turned off with a button, the button is only for turning it on. Turns off by itself after 10 seconds of inactivity. I have already mentioned the impossibility of a quick change of batteries and not very convenient assembly with screws.
Also for 1 battery, like the ML-102. It has a button, 5 indicators, supports a "special" mode for the iPhone. Includes adapters for various phones and a flashlight. There are no specifications for the output current.
Alas, I could not disassemble it, so we will not see the insides. The plastic is very tight.
Under the same conditions, charging could only give out 0.66A in normal mode and 0.87 in special mode (which is for the iPhone):
Special mode is enabled only for a couple of minutes, so do not flatter yourself with high values.
Interestingly, it can also work with a heavily discharged battery (possibly sagging in voltage at the same time):
This is observed only in the "special" mode, but for emergencies it will do!
Summing up: collected on the conscience, has been working for two years. The standard cable was of poor quality, soldered a new one. Charging is slow, but more efficient - it will work to the end, limiting the output current. The only one that can be turned off with the button during operation!
Of the minuses - only one USB connector. Through it, charging from the network takes place. So without a special cable (USB - USB), it will not work to charge it by itself.
What conclusion can be drawn from the considered options? There are no universal things. To each his own. It’s more convenient for me to throw a 1 * 18650 power bank and several batteries into my backpack. Ruinovo is more convenient for someone - he screwed it in and forgot until you have to change the batteries. In general, I told you all the possible problems when choosing a portable charger - make no mistake.
But I did miss one point. Batteries! Not to pull them out of laptops? After all, we need high-quality ones so that such a charge is enough for a long time. And the Chinese strive to slip cheap stuff under the guise of a normal battery:
First of all, remember - there are no 18650 batteries with a capacity greater than 3400 mAh. And even those are achieved only in non-standard modes of operation (which are not available in standard power banks). Standard capacity is 2200 mAh, better ones have 2600 mAh
Also, do not take Chinese brands (UltraFire, TrustFire, FandyFire ... ***Fire) - you can’t understand where the original is and where the fake is, you can run into batteries with a capacity of 1000 mAh and even 250 mAh instead of the indicated 2600. (see photo above )
If you still want to save money, pay attention to the captions about the actual battery capacity on the site:
If the real capacity is less than 2200 mAh, don't take it. It's not worth it.
Interested in other things? Write in the comments! Perhaps it is your topic that I will choose for review next time.
Hello. Today we will talk about a fairly well-known device. The twenty-first century is the age of information technology. Portable devices that constantly lack power. Especially smartphones based on the Android operating system are very gluttonous. The browser alone uses about 80% of the smartphone's battery capacity. And, as you know, the Internet is now used very often. Even better to say - constantly! Checking the weather, the dollar exchange rate, answering messages on social networks, checking a kidney, ordering pizza for work, ordering a taxi, booking a hotel room - this is far from full list the purpose of the smartphone as an intermediary between the user and the Internet. In such cases, you will not move far from the outlet. And if there is no access to the outlet ...
In general, where there is a problem, a solution to the problem is born, and in this case it was proposed to assemble a portable charger, it is also an external battery, it is also a powerbank (power bank).
A kind of portable charger for replenishing the battery of your smartphone.
What is Power Bank?
Translated into Russian, Power Bank is an energy bank. That is, an array of batteries assembled in one case. There are several spellings of this word Powerbank and Power Bank, as well as external battery for smartphone/tablet, mobile battery and autonomous Charger .
To put it simply, Power Bank is an outlet in your pocket.
What is a Power Bank for?
Frame external charger has a universal output (USB) and an input (most often microUSB). This means that from the Power Bank you can energize everything that is connected via USB, from smartphones, tablets, navigators and players, to set-top boxes and walkie-talkies.
On the market today there is a huge selection of Power Banks of different companies, capacities, designs, sizes, reliability. How to choose what is right for you?
How to choose Power Bank?
Just like before buying anything, first ask yourself: Why do I need a Power Bank?».
If you are going on a long journey and the socket “does not shine” for you for several days, then you should look at capacious batteries from 15.000mAh to 20.000mAh, such as . In addition to capacity, PINENG has a huge mass of pluses, more about which you can read.
Or maybe you are wandering around the city all day, showing presentations from your tablet, you have a million calls and there is absolutely no time to sit in a cafe, recharging your gadget. Then elegant or . You know, these two Power Banks are not a shame to put next to the iPhone, as they both have the same stylish design.
But not only power is worth paying attention to. Also, an important difference external batteries is the number of USB outputs. Agree, there is a difference - either you charge one smartphone, or you charge both a smartphone and a tablet. Moreover, each of the gadgets is saturated with the energy of the force that is recommended to it. All PINENG presented in our store have this opportunity.
You should also pay attention to the presence of a led-flashlight, this nice bonus can be very useful to you. This is not just a flashlight, but a flashlight with powerful batteries, which means it will shine for a long time.
If you have any questions -! We will be glad!
And even if you don’t understand anything about milliamps and so on, you can just tell us about your tasks for Power Bank, and we will help you make a choice!
Select power bank or usb tester in the catalog
Most people have laptops at home, or at work they have laptops, in extreme cases, acquaintances have laptops.
Each laptop has its own battery, which, after time, ceases to hold a charge and is thrown away, and replaced with a new one.
What a wild waste I will scream, why throw away something that might still be useful to us.
And why is it useful to us, you ask? Yes, it’s just that most laptop batteries are a case, inside of which the charge controller of the cells and the 18650 cells themselves. And often 10-30% of the cells fail, the rest are still quite alive.
We buy here such a power bank.
Photo outside and inside
Characteristics:
Charging input Micro USB: 5V/2A
Max consumer current: usb1 + usb2 = 0.5A / 1A / 2A
Battery level (25% red, 50% green, 75% green, 100% green)
Battery type: lithium battery 18650 3.6-3.7V
USB output: 2pcs
Possibility of charging while consumers are connected
Battery protection: reverse polarity, overdischarge, overcharge, short circuit, overcurrent
Flashlight
Size: 115*78*21mm
We stock up on a flat screwdriver, pliers, a multimeter and a soldering iron. 
We carefully disassemble the laptop battery along the junction line, you can break the latches, we no longer need them, the main thing is not to damage the elements. 
And here we have all the insides. 
We cut off all the wires from the power controller and throw it away. 
We take out a block of elements connected by a metal tape. 
Carefully tear off the tape from each element, on both sides. 
As a result, we get these elements 18650
Next, we check the voltage on each element using our multimeter. If the voltage is less than 1V, then we throw out such an element. If more than 1V but less than 3.6V, then the element may not be charged because the charge controller will not see it. You can try to revive it by connecting it for a short time to a 4.7-5V power source, for example from a computer, after which the voltage on the element usually rises and the charge controller starts charging it. 
We checked all the elements, threw out some, left the rest.
We put in the power bank we bought and ... nothing works, what's the problem?
We measure the voltage at the contacts of the battery compartment and see that there is no voltage, but the thing is that the element does not reach the positive terminal to the contact. 
We take a soldering iron and solder not large droplets on the positive contacts of the power bank. 
We insert the elements again, measure the voltage at the contacts, now as it should.
It remains to put the power bank on charge through the native charge controller or, as I did, using the IMAX B6 charger.
As a result, we get an excellent power bank, with a capacity from 4000 mAh to 8000 mAh, although there may be elements with even higher capacity in some batteries.
Pros:
Compartment for 4 elements
The switch allows you to select the Max discharge current of the bank
USB 2pcs
Flashlight
Compact
Minuses:
Not good bright flashlight
An external mobile battery or power bank for a laptop can become the best option to increase the operating time of your portable computer.
With an average capacity of built-in batteries of 3000-6000 mAh, the average duration of using the gadget does not exceed 3-5 hours.
A good power bank will increase this time by at least three times, allowing you to work on a laptop even with a complete absence of electricity for several days.
In order to figure out which model is best to purchase today, several important factors should be taken into account, ranging from capacity to functionality and price.
Types of power banks
The modern one is a universal battery suitable for several types of devices at once.
For ease of use, the array with batteries is enclosed in a case with one or more outputs ( USB and microUSB).
Various models of external batteries differ in the following parameters:
- power in the range of 1000-50000 mAh;
- the number of connectors; the presence of a charge indicator;
- battery type (lithium ion or lithium polymer). They are distinguished from conventional batteries by their long service life and maximum energy intensity;
- dimensions and weight, which usually depend on power;
- design;
- device manufacturer.
The standard external power supply model is a small rectangle that resembles an mp3 player or portable hard drive.
They are charged from the network (using a conventional charger), from the USB connector of a PC, and even from that laptop, to increase the resource of which they will be used.
Features of choosing a battery
The main factors when choosing mobile external batteries are size, capacity and manufacturer.
The next important point is instrument design and durability.
If the device will be used to charge several devices, you should pay attention to its functionality - the presence of a charge indicator and several inputs.
Characteristics
The main characteristic of the device, which is worth paying attention to, is the name of the manufacturer.
Popular brands in this segment are Powerplant, Drobak and Xiaomi, issuing powerful batteries, which are suitable for any type of mobile electronics, including laptops.
Little-known manufacturers are not as reliable, and their claimed battery capacity may actually be lower.
Next item- the degree of protection of the external battery from dust, moisture and shock.
And, if impact resistance is not the most important characteristic, then preventing the ingress of liquid and dust particles can be called an important option.
All functional models of famous brands have such protection - not to such an extent that they dive with them, but enough to stay in a room with high humidity.
Fully protected, including drop protection, the external battery option is usually recognizable by the orange or dark red design of the case.
Another rather important characteristic of the device is its capacity. The larger it is, the longer the laptop will work without recharging from the network.
The minimum capacity batteries are not suitable for use in order to extend the charge of the laptop. To do this, choose models for 20000-30000 mAh and more.
A volume of 20 thousand mAh is already enough to increase the operating time of an average portable PC by 3 times, 30 thousand is enough for a fivefold increase.
Although, if mobility plays the main role, you should pay attention to devices with a capacity of no more than 10,000 mAh - they are also quite productive, while weighing no more than 200–300 g and fitting in a laptop bag pocket.
Advice: you should not chase after a large capacity, looking for batteries for 40-50 thousand mAh - most often these are fakes with smaller parameters.
An additional parameter requiring attention from female users and youth is instrument design.
Often, such equipment is not just made in the usual discreet color, but can have an original and eye-catching look.
When choosing a case material - plastic or metal - it is worth noting that often modern plastic is not much inferior in strength to aluminum.
Moreover, many new models of portable chargers are enclosed in a polymer shell, having no less wear resistance.
At the same time, they are more pleasant to the touch than metal options.
Functionality
Functionality various models may differ markedly. So, for example, some are able to charge at the same time no more than one laptop.
With the help of others, you can increase the operating time of your laptop, tablet, smartphone, or several laptops at the same time.
If the number of charging connectors reaches 3 or even 4, an additional device for connection can be, for example, a small USB lamp.
Connectors differ in current strength, on which the charge time depends. For a tablet or smartphone, a 1 or 2 A USB port is sufficient.
The laptop may require a 3.2A connector that can charge its main battery faster.
An additional advantage of the device can be a digital indicator, which shows how much percent of the charge is left.
While the package with a built-in LED lamp will ensure the use of the power bank also as a temporary source of illumination, moreover, it works much longer compared to even conventional hand lamps.
The compatibility of models produced in the past few years can not be considered. All of them are suitable for charging any gadget.
Moreover, some power banks come with adapter cords designed for most connector options - from USB and microUSB to inputs for various laptop models.
Advice: when charging a laptop, the second battery must be connected to the power supply. Since if you connect them to the USB connector, the battery will not charge the portable computer, but, on the contrary, will be recharged from it.
The most powerful
The most powerful of all consumer trusted portable chargers is the PowerPlant K2 50000.
This battery can replace the batteries of ten laptops and 15 medium tablets at once.
Complete with adapters allows you to use it specifically for charging portable computers.
Among the security options there is protection against short circuit, spontaneous discharge, and overheating.
Technical specifications:
- capacity: 50000 mAh;
- adapters included: Toshiba, Sony, Acer, Samsung, Dell, Lenovo and HP laptops;
- price: from 12000 rub.
The best solar powered option
A good option for a power bank for a laptop would be model KS-303, capable of charging not only from the electrical network, but also from the sun.
Among the additional features of the device are the protection of connectors from moisture and a rubberized housing.
Gadget characteristics:
- capacity: 20000 mAh;
- peculiarities: 220 mA solar battery;
- price: from 3000 rub.
The most functional in the budget segment
Model Defender ExtraLife Maxi differs not only in its huge capacity (the manufacturer claims 30 thousand mAh, although testing showed from 20 to 22 thousand, which is also not bad), but also in the presence of 4 USB inputs at once.
At the same time, the battery, which has a charge indicator, is equipped with adapters only for smartphones.
The laptop owner will have to buy a separate adapter for their device - although with a battery cost of up to 3000 rubles, this is not such a big disadvantage for a user whose main task is to simultaneously charge 4 devices (for example, a laptop, 2 smartphones and a tablet).
Device parameters:
- capacity: up to 30000 mAh;
- adapters: Only for smartphones and tablets;
- prices: from 2700 rub.
The most compact
Compact external battery mini power bank Xiaomi Mi Power Bank 20000 will not only charge your laptop, but also take up almost no space in your luggage.
Its dimensions are only 14 × 7 cm, and the weight does not exceed 338 g.
At the same time, the battery charges up to 2 mobile devices simultaneously and has an affordable price.
Features of its use- output current 3.6A, so that while charging on a laptop, you can also work.
External batteries for mobile devices are needed by almost every user, because they run out quite quickly, especially when the processor is under high load.
Advantages
- Relatively low price - high-capacity batteries are expensive, while cheap analogues quickly fail, therefore, if the necessary components for assembly are at hand, then it is profitable to assemble such a device;
- In the event of a malfunction, a home-made battery is easier to fix, since it will have a removable case, and you will understand the structure of the circuits;
- The ability to make the device of the desired capacity is large enough;
- You can make a replaceable body of the device so that in case of damage you do not have to change the entire power bank;
- From an environmental point of view, recycling (for example, from batteries with a broken charge controller) is also beneficial;
- original or strange appearance devices for some users may also be attractive.
- A lot of time is spent on the manufacture of the battery;
- You need to have some initial skills to assemble it;
- Poor appearance of the device;
- Not all materials for the manufacture of such a device may be at hand;
- In most cases, the service life of such a device is lower than that of the factory counterpart;
- In the simplest versions of home-made equipment, there are no charge indicators, on and off buttons, which is not convenient (if they are present, self-assembly will become excessively long, complicated and expensive);
- Theoretically, such a device can harm the battery. mobile device and even cause it to burn out (but there is such a risk when using any power bank made by a brand different from the brand of your device);
- When collecting such a battery, in any case, a charge controller is also needed, and taking into account the cost of their purchase, the final price of the device will not be so low.
Attention! Do not undertake self-assembly if you do not have enough skills for this. In the event of an error in the assembly of circuits, the device can cause significant harm.
materials
You can make your own external battery from charge carriers of any type.
The most common materials are:
- finger batteries;
- Batteries from old phones with sufficient capacity;
- Batteries from old laptop batteries.
In any case, regardless of the media you choose, you will need a charge controller to which the USB cable will be connected.
Naturally, it must be taken into account that all media must be in good condition.
From phone batteries
This is a fairly simple way. The device turns out to be relatively compact and convenient, as well as capacious.
To make it, you will need 6 batteries - accordingly, the larger their capacity, the greater the total capacity of the power bank.
You can make it like this:
- Put three batteries on top of each other, orienting the contacts in one direction, and wind the stack with tape - neatly and tightly enough;
- Repeat the same with the other three batteries;
- Make sure that all terminals are directed in the same direction and are not covered anywhere with adhesive tape;
- Now solder the extreme terminals in pairs in both piles - pluses with pluses and minuses with minuses, respectively (it will be easier to do this if the batteries were originally about the same size);
- The middle terminals do not need to be touched;
- Now prepare the case - it can be any type of plastic box;
- Mark the place in the box where the future charge controller will be located, and cut out the area for USB;
- Attach both stacks of batteries to the controller;
- Fasten the device in the case in the appropriate place and close the case.
Leave the plastic box detachable for maintenance and cleaning, as dust can enter through the cut hole.
Usually, such a device is enough for 4-5 charge cycles of an average, not very powerful, smartphone.
Remember that only hot melt adhesive should be used for any work to fix the equipment in the case.
From finger batteries
This method is also simple, but it is rather unreliable.
Such batteries are heavy and do not have sufficient capacity.
But they are cheap and easy to assemble.
- Take two matchboxes, cut off their top sides;
- Glue the boxes base to each other;
- Place two batteries in each box, orienting them in one direction with the poles;
- With the help of clips from the stapler, create contacts between the batteries from two boxes - minus with minus, plus with plus, on both sides;
- Secure the brackets with wire (the main thing is not to use tape, as it can sometimes isolate the contacts);
- Place the entire device in a box where it will be compactly fixed and the contacts will not be damaged;
- Find a case in which to place the entire battery - mark the place in it where the USB output will be located;
- Solder a short wire to the USB output;
- Fix the outlet in the device case;
- Solder the battery to the USB output;
- Fix the entire structure in the housing with hot glue.
The device is ready. This power bank has a very small capacity, but it is compact, light weight and easy to carry around.
From car charger
In this way, quite powerful high-capacity batteries are obtained. They are suitable for recharging tablets, laptops and other energy-intensive devices.
18650 batteries are most suitable for this purpose.
You can get them from laptop batteries, but the elements must be working.
Working batteries are sold very cheaply on various sites, but with burnt controllers - just right for this product:
- Remove the batteries from the batteries - you only need 6 pieces;
- Prepare the case of the future battery - cut or drill holes in it for the USB input and for the switch (such charging makes it possible to make a switch);
- Solder together two blocks of 4 batteries according to the diagram in the picture;
The capacity of such a device should be enough for about 2-3 full charge cycles of a sufficiently powerful device with high power consumption. In order to start charging, connect and then press the enable relay. When turning off, first drag the relay to the off position, and then unplug the device.
From a flashlight
A standard LED flashlight can also be turned into a power bank.
To do this, you will need the flashlight itself with a 3.7 volt battery, a charge controller, as in the previous examples, a voltage converter with a USB output.
Such a converter is needed only in this method self-assembly device, since the output of 3.7 volts needs to be converted to the 5 volts necessary to charge the phone.
- Disassemble the flashlight and find the resistor to which the LED is attached;
- Unfasten the LED;
- Remove the metal plug with which the flashlight was previously charged;
- In its place, install a current converter with a USB output;
- Now solder both poles of the flashlight battery to the controller - both plus and minus to the appropriate places;
- Take a close look at the controller - it has two contacts - OUT + and OUT-;
- Attach a 5 volt converter to them;
- Release one of the switch contacts;
- Solder the converter to the released contact;
- Use a voltmeter to check if the converter is working;
- If it does not work, then resolder to another pin at this stage;
- Check again - everything should work now;
- Now attach the controller and converter to the flashlight body with hot glue;
But even if they are, you need to find all the components of the device, and if batteries from non-working batteries are easy to find, then in most cases you will have to buy a charge.
Given the cost of the controller, USB output and, in some cases, the converter, the economic feasibility of self-assembly seems to be minimal.
But if for some reason such components are at hand, then an additional power bank will not be superfluous.
a. A smartphone is a device that has become an indispensable device for all people to communicate. They are used to access the Internet and often for a long time. But smartphones have one drawback - it's time. battery life. In the best case, the battery will work without recharging for one day, and if you actively use it, then several hours. This article and the accompanying video show you how to make a powerful homemade Powerbank that can even charge simultaneously for a smartphone or tablet, or a combination of the two.
You can buy a baby monitor, which is described at the beginning of the video, and all the components of the power bank in this Chinese store. How to receive a cashback (refund) in the amount of 7% of the price of all purchases is on our website. Download schematic, board and other project files.
In order to improve the performance of mobile phone batteries, portable chargers were ordered, which are commonly called poverbank. But in a single form, such a device is not even half capable of charging the phone's battery. And even three such devices do not give a way out of the situation. Buying a powerful power bank is quite expensive. A normal powerbank, say, with a capacity of 10,000 milliamps costs 25-30 dollars. Given this and the long waiting time for the package, it's easier to make your own version.
Description of the power bank scheme
The powerbank circuit consists of three main parts. This is a charge controller. lithium batteries with auto-off function when fully charged; battery compartment with parallel connected lithium-ion batteries 18650 standard; a 5-10 amp power switch from a computer power supply; boost converter to increase the voltage from the battery to the desired values of 5 volts, which are needed to charge a phone or tablet; USB connector to which the charging device is connected.
In addition to simplicity and low cost, the presented circuit has a high output current, which can reach up to 4 amperes and depends on the rating of components such as a field effect transistor, an output Schottky diode and an inductance. Chinese counterparts are capable of providing an output current of not more than 2.1 amperes. This is enough to charge a couple of smartphones at the same time, and our power bank can handle 4-5 smartphones.
Consider the individual components of the structure. As a power source, 5 parallel-connected 18650 batteries from a laptop. The capacity of each battery is 2600 milliamps per hour. An adapter or inverter case is used, but another suitable case can be used. We will use a charge board purchased as a charge controller. The charge current is about 1 ampere. An inverter that will increase the voltage from the battery to the required 5 volts can also be taken ready-made. It is very cheap. Maximum output current up to 2 amps.
Circuit Assembly
At the first stage, we fix the batteries, fasten them together with a glue gun. Next, you need to connect to battery controller to check how the charging process is going. You also need to find out the battery charge time and understand if the auto-shutdown works when fully charged. Everything is signed in detail on the board.
You can charge from any USB port. The indicator should show that charging in progress. After 5 hours, the second indicator lights up, which means that the charging process is completed. If a metal case is used, additionally insulate the batteries with a wide adhesive tape.
One of the main components of the circuit is a step-up dc-dc converter, an inverter - a voltage converter. It is designed to raise the voltage from the batteries up to 5 volts, needed to charge the phone. The voltage of one battery is 3.7 volts. Here they are connected in parallel, so an inverter is needed.
The system is built on a 555 timer - a field-effect transistor and output voltage stabilization, which is set using a zener diode vd2. A zener diode may have to be selected. Any low power zener diode will do. 0.25 or even 0.125 watt resistors. Choke L1 can be removed from the computer power supply. The diameter of the wire is at least 0.8, it is best to make 1 millimeter. The number of turns is 10-15.
A frequency-setting node is assembled in the circuit, which sets the operating frequency of the timer. The latter is connected as a rectangular pulse generator. With this selection of components, the operating frequency of the timer is about 48-50 kHz. Gate limiting resistor R3 for a 4.7 ohm FET. Resistance can be from 1 to 10 ohms. You can replace this resistor with a jumper. Field-effect transistor any medium power with a current of 7 amps. Suitable field workers from motherboards. A small reverse conduction transistor vt1. A kt315 or other low power reverse conduction transistor will do. Rectifier diode - it is desirable to use a Schottky diode with a minimum voltage drop across the junction. Two containers stand as a power filter.
This inverter is pulsed, it provides high efficiency, high stabilization of the output voltage, does not heat up during operation. Therefore, power components do not need to be installed on the heat sink. If there are difficulties with Schottky diodes, then you can use diodes that are in computer blocks nutrition. Dual to-220 diodes are found in them.
In the photo below, the inverter is assembled.
Can do printed circuit board. There is a link in the description.
5 volt inverter testing
We check the inverter for operability. The smartphone is charging, as you can see, the charging process is in progress. Output voltage keeps at 5.3 volts, which is fully compliant. The inverter does not heat up.
Final body assembly
From a piece of plastic, we need to cut the side walls. The charge controller has two LED indicators that show the percentage of charge. They need to be replaced with brighter ones and brought to the front panel. Two holes for micro USB connectors are cut out in the side wall, that is, two devices can be charged at the same time. There are also holes for LEDs. A hole for the controller, that is, for charging the built-in batteries. A small hole for the power switch will also be made.
All connectors, LEDs and the switch are fixed with a glue gun. It remains to pack everything into the case.
A USB tester is connected to the output of the device. It can be seen that a voltage of 5 volts is firmly held at the output. Connect mobile phones and try to charge them from a homemade Power Bank. Two smartphones will be charged at once. The charge current jumps to 1.2 Amperes, the voltage is also normal. The charging process is running successfully. The inverter is working flawlessly. It turned out compact and, most importantly, stable. The circuit is easy to assemble, all familiar components are used.
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