Material used from the channel of blogger Aka Kasyan. A smartphone is a device that has become an indispensable communication device for all people. They are used to access the Internet and often for a long time. But smartphones have one drawback - battery life. In the best case, the battery will work without recharging for one day, and if you use it actively, then for several hours. This article and accompanying video show you how to make a powerful homemade Powerbank that can even charge your smartphone or tablet or a combination of both simultaneously.
You can buy the baby monitor, which is described at the beginning of the video, and all the components of the power bank in this Chinese store. There is an article on our website about how to receive cashback (cost refund) in the amount of 7% of the price of all purchases. Download the schematic, board and other project files here.
Why is it profitable to make a power bank yourself?
In order to improve the performance of mobile phone batteries, portable chargers were ordered, which are popularly called power banks. But in its single form, such a device is not even half capable of charging a phone battery. And even three such devices do not provide 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. Considering this and the long waiting time for the parcel, it is easier to make your own option.
Advantages
Positive:
- Relatively low price - high-capacity batteries are expensive, but cheap analogues quickly fail, therefore, if the necessary components for assembly are on hand, then it is profitable to assemble such a device;
- If problems arise, it is easier to repair a homemade battery, since it will have a removable case, and you will understand the structure of the circuits;
- The ability to make a device of the desired capacity – large enough;
- You can make a replaceable device case so that in case of damage you do not have to change the entire power bank;
- From an environmental point of view, recycling lithium-ion batteries (for example, from batteries with a broken charge controller) is also beneficial;
- The original or strange appearance of the device may also be attractive to some users.
Negative:
- Making a battery takes a lot of time;
- You need to have some initial skills to assemble it;
- Poor appearance of the device;
- Not all materials for making such a device may be at hand;
- In most cases, the service life of such a device is lower than that of its factory counterpart;
- The simplest versions of homemade equipment do not have charge indicators or on/off buttons, which is inconvenient (if they are present, self-assembly will become excessively long, complicated and expensive);
- Theoretically, such a device can harm the battery of a 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 assembling such a battery, in any case, you need a USB output and a charge controller, and taking into account the cost of purchasing them, the final price of the device will not be so low.
<Fig.
1 Simple diagram> Attention! You should not undertake self-assembly if you do not have enough skills for this. If there is an error in assembling the circuits, the device can cause significant damage to the smartphone or tablet.
<Fig. 2 Principle>
Description of the power bank circuit
The powerbank circuit consists of three main parts. This is a lithium battery charge controller with an auto-shutoff function when fully charged; battery compartment with parallel-connected 18650 lithium-ion batteries; 5-10 amp power switch from the computer power supply; a boost converter in order 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 device to be charged is connected.
In addition to its simplicity and low cost, the presented circuit has high output current values, which can reach up to 4 amperes and depends on the rating of components such as a field-effect transistor, a Schottky diode at the output and inductance. Chinese analogues are capable of providing an output current of no 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.
Let's look at the individual components of the structure. The power source is 5 parallel-connected 18650 batteries from a laptop. The capacity of each battery is 2600 milliamps per hour. The housing used is from an adapter or inverter, but another suitable housing can be used. As a charge controller we will use a charge board purchased here. The charging current is about 1 ampere. You can also take a ready-made inverter that will increase the voltage from the battery to the required 5 volts. It's very cheap. Maximum output current up to 2 amperes.
Circuit assembly
At the first stage, we fix the batteries and fasten them together using a glue gun. Next, you need to connect the controller to the battery to check how the charging process occurs. You also need to find out the battery charge time and understand whether auto-shutdown works when fully charged. Everything is labeled in detail on the board.
You can charge from any USB port. The indicator should show that charging is in progress. After 5 hours, the second indicator lights up, which means the charging process is complete. If a metal case is used, the batteries should be additionally insulated using wide tape.
Read also: Connection diagram for an ammeter in a charger
One of the main components of the circuit is a step-up dc-dc converter, an inverter - voltage converter. It is designed to raise the voltage from the batteries 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 stabilization of the output voltage, which is set using a zener diode vd2. You may have to pick up a zener diode. Any low-power zener diode will do. Resistors of 0.25 or even 0.125 watts. Inductor 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.
The circuit contains a frequency-setting unit that sets the operating frequency of the timer. The latter is connected as a square 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 field effect transistor. Resistance can be from 1 to 10 Ohms. You can replace this resistor with a jumper. Field effect transistor of any average power with a current of 7 amperes. Field switches from motherboards are suitable. Small reverse conduction transistor vt1. A kt315 or other low-power reverse conduction transistor will do. Rectifier diode - it is advisable to use a Schottky diode with a minimum voltage drop across the junction. Two containers serve as a power filter.
This inverter is pulsed, it provides high efficiency, high output voltage stabilization, and does not heat up during operation. Therefore, there is no need to install power components on the heat sink. If there are difficulties with Schottky diodes, then you can use the diodes that are found in computer power supplies. Dual to-220 diodes are found in them.
The photo below shows the inverter in assembled condition.
You can make a printed circuit board. There is a link in the description.
Testing a 5 volt inverter
We check the inverter for functionality. The smartphone is charging, as you can see, the charging process is in progress. The output voltage is kept at 5.3 volts, which fully complies with the standards. The inverter does not heat up.
Final assembly into the body
We need to cut out the side walls from a piece of plastic. The charge controller has two LED indicators that show the charge percentage. They need to be replaced with brighter ones and displayed on the front panel. There are two holes cut out in the side wall for micro USB connectors, which means you can charge two devices 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 will also be made for the power switch.
All connectors, LEDs and switch are fixed with a glue gun. All that remains is to pack everything into the case.
A USB tester is connected to the output of the device. It can be seen that the output voltage remains firmly at 5 volts. Let's connect mobile phones and try to charge them from a homemade Power bank. Two smartphones will be charged at once. The charging current jumps to 1.2 Amperes, the voltage is also normal. The charging process is progressing successfully. The inverter works flawlessly. It turned out compact and, most importantly, stable. The circuit is easy to assemble; familiar components are used.
Your smartphone always discharges at the wrong time, have you thought about buying a Power bank? Take your time, now we will tell you how to make an external battery with your own hands! 4 interesting methods for making a portable charger - choose any one.
It is not always possible to charge a gadget from the mains. In this case, portable charging is simply necessary. But since this is a fairly popular item, there is a lot of low-quality junk on the market. It's easy to make a wrong choice. But let’s not be mistaken - it’s better to just make our own Power bank.
From phone batteries
Mobile phone batteries are used to create a compact, small-capacity power bank. It is recommended to use at least 6 similar products of the same capacity, which are connected into a common circuit and then covered with a plastic casing.
DIY Power Bank option.
To reduce the size, you need to assemble 2 cans; masking tape or insulating tape is used to hold the elements. To simplify the switching circuit, the batteries are placed with contact pads in one direction.
Then the extreme contacts of the current sources in each bank are connected with a copper cable. The wiring is attached by soldering; before connection, the polarity of the elements is checked with a test device. The batteries are connected in a parallel circuit, which allows increasing the capacity of the future Power Bank.
When assembling, only the outer contacts on each current source should be used; the middle pad is not used (this element is designed to control the temperature of the battery). The second bank is switched using a similar scheme.
Prepare a plastic case with suitable dimensions, which should accommodate the charging control unit and the previously assembled battery banks.
The casing houses the connecting wiring and the back of the USB connector.
After connecting the cables, the components are placed in a box, and plastic or foam pads are installed to limit movement. It is necessary to test the operation of the received device; the capacity of the installed elements should be enough for 3-5 charges of the smartphone battery.
Hot melt adhesive, screws or latches are used to connect parts of the casing and additional covers. The type of design depends on the configuration and design of the parts. It is recommended to make a detachable design, which will allow you to remove contaminants accumulated during operation and replace failed elements.
A good result is achieved by using a plastic water pipe, which is heated with a hair dryer and pressed around a dummy battery cans.
Method 1. Old battery - new opportunities
How to make a Power bank from old phone batteries? - Just. A step-by-step description of the method will help you avoid mistakes.
- Battery from an old phone
- Wires
- Controller
- USB input
- Electrical tape, tape, hot glue.
- We take an old mobile phone and remove the battery from it. We will need 3, 6 or 9 such batteries. The more, the longer the device will last.
- We stack 3 drives next to each other, fix them lengthwise with tape, and wrap them across them with electrical tape. In this case, the terminals remain open.
- We find a suitable housing. Even a simple soap dish can fulfill this role, it all depends on the size.
- Using 2 wires, we connect 3 pieces together: one wire is “+”, the second wire is “-”. We do not connect the central terminals of the battery. They serve as a temperature sensor and their whole point is to demonstrate the remaining charge for a specific device.
- We mark the location of the controller and make a hole to insert the input.
- We attach all the parts with hot glue and you're done!
Read also: How to crimp a twisted pair socket
Power bank made from obsolete phone batteries
That's it, in just 6 steps we got a portable battery.
In principle, the manipulations are simple. The only thing that can stop you is that not everyone has such a number of outdated batteries.
How to disassemble a power bank
Most inexpensive (and expensive) models are assembled without hardware. The body parts are connected with glue or similar compounds. Therefore, such a power bank can only be opened by mechanical force - with a sharp knife or other object. Disassembly should begin with cutting the adhesive layer around the perimeter as deeply as possible. This operation must be performed carefully so that the knife does not slip and cause injury.
Then the released housing elements must be pryed up and carefully removed. This must be done carefully - parts of the power bank may be attached to the shell parts; with excessive force, the connecting wires can be torn off, buttons, boards, etc. can be broken.
Disassembling the power bank
Method 2. The lantern will illuminate the path, the phone will “feed”
Do you have a flashlight? Now you will learn how to transform a flashlight so that it not only illuminates the path, but also helps you stay in touch.
Flashlight charger
- Flashlight with 3.7 V storage
- Voltage converter with built-in USB output
- Energy charge controller.
- Let's disassemble the flashlight.
- The resistor with the soldered LED must be removed. This makes it possible to change one of the glow modes to another mode - charging.
- In the place where the plug was previously located to charge the flashlight, we place a converter with an output.
- We solder the “+” and “-” from the battery to the battery charge controller. After this, we solder a 5 V converter to the OUT+/OUT- contacts of the provided controller.
- We check the functionality. If necessary, we resolder it.
- We attach the converter and controller. Ready!
This modern lantern will give you a double advantage on your hike. And there is light, and it’s not scary to be left without communication at any moment.
The main thing here is to do everything correctly, you will definitely have a flashlight, and then it’s a matter of technology.
Manufacturing materials
The basis for making homemade DC sources are portable batteries, cell phone batteries or laptop batteries. It is acceptable to use AA or AAA alkaline batteries, as well as rechargeable nickel-metal hydride batteries of similar housing dimensions.
Additionally, a USB connector and a controller that maintains a stable voltage in the power circuit are purchased.
It is possible to manufacture structures that use solar energy to replenish the charge. The design of the product includes a photosensitive element that converts sunlight into electrical energy. The panel is connected to a charging control unit equipped with a microUSB port for connecting to an external power circuit, since the battery cannot be charged from solar radiation.
Method 3. How to make a portable charger from batteries
This method is somewhat similar to the first one, but here we will use regular lithium-ion drives 18650 2200 mAh 3.6 V
- Li-ion batteries 18650 2200 mAh 3.6 V. - 8 pieces
- Car charging
- USB input
- Block housing with car relay
Portable device diagram
In just a few steps we will again achieve what we want - we will make our own Power Bank.
- You need to cut 2 holes in the housing: for the switch and for the entrance.
- We solder storage batteries together in groups of 4. You can see the diagram in the image. We install them in the case.
- We solder the combined blocks to the switch, then from the switch to the board, from the board to the USB input. This process is also shown in the diagram.
This is perhaps the fastest way. Such a device will work even for an amateur due to its simplicity. Just 3 steps and your DIY external battery for your phone is ready.
Conclusion
Is it worth assembling the battery yourself? Firstly, this requires appropriate skills and a fairly large amount of free time.
But even if they are, it is necessary to find all the components of the device, and if batteries from non-working batteries are quite easy to find, then in most cases you will have to buy a charge controller.
Considering the cost of the controller, USB output and, in some cases, the converter, the economic feasibility of self-assembly seems minimal.
But if for some reason such components are at hand, then an additional power bank will not be superfluous.
Method 4. External energy storage with a solar battery
Another interesting option. As daylight hours begin to increase, it is timely to discuss the benefits of solar energy storage. You'll see how to make a portable charger that can be charged from solar energy storage panels.
- Lithium-ion energy storage 18650 format,
- Case from the same drives
- 5V 1A voltage boost module.
- Charge board for battery.
- Solar panel 5.5 V 160 mA (any size)
- Wiring for connection
- 2 diodes 1N4007 (others are possible)
- Velcro or double-sided tape for fixation
- Hot melt adhesive
- Resistor 47 Ohm
- Contacts for energy storage (thin steel plates)
- A pair of toggle switches
Read also: What is the stroke of an internal combustion engine
Basic circuit of an external battery
- Let's study the basic circuit of an external battery.
The diagram shows 2 connecting wires of different colors. Red is connected to “+”, black to “-”.
- It is not recommended to solder the contacts to the lithium-ion battery, so we will put terminals in the housing and secure them with hot glue.
- The next task is to place the voltage increase module and charging board for the battery. To do this, we make holes for the USB input and USB output 5 V 1 A, a toggle switch and wiring to the solar panel.
- We solder a resistor (resistance 47 Ohms) to the USB output, on the reverse side of the module that increases the voltage. This makes sense for charging an iPhone. The resistor will solve the problem with the same control signal that starts the charging process.
- To make the panels easier to carry, you can attach the panel contacts using 2 small female-male contacts. Alternatively, you can connect the main body and panels using Velcro.
- We place a diode between 1 contact of the panel and the energy storage charge board. The diode should be placed with the arrow pointing towards the charge board. This will prevent the solar panel from draining the storage battery.
How many charges will this Power Bank last? It all depends on the capacity of your battery and the capacity of the gadget. Remember that discharging lithium drives below 2.7 V is highly undesirable.
As for the charge of the device itself. In our case, we used solar panels with a total capacity of 160 mAh, and the battery capacity was 2600 mAh. Therefore, under the condition of direct rays, the battery will charge in 16.3 hours. Under normal conditions - about 20–25 hours. But don't let these numbers scare you. It will charge via miniUSB in 2-3 hours. Most likely, you will use the solar panel when traveling, hiking, or long trips.
Assembly process and diagram
We cut out holes in the case for the switch and USB input.
We solder the batteries according to the diagram, into two batteries of 4 each, and install them in the case.
Next we solder the batteries to the switch, and from the switch we solder them to the board, as in the diagram, and from the board we solder them to the USB input. See below for a photo of the finished device.
