Power bank from old batteries. Cheap DIY powerbank
Nowadays, electricity is one of the most important things. It is used everywhere, for lighting, communication or simply to operate household devices. And electricity, like everything else, tends to run out. It is possible that at any moment your phone or laptop may be dead, and connecting it to the network will be impossible in this situation.
Then it comes to the rescue Power bank- external battery. With its help you can extend the life of your device. You can see an example of a Power bank in the photo below.
In principle, such things can now be freely found in electrical stores. However, external batteries cost a lot of money there, and it is not always appropriate to buy one when you can make it yourself at home. Therefore, we would like to present several simple instructions on creating a Power bank at home.
External battery from mobile phone batteries
One of the most simple ways create a Power bank at home - assemble it from batteries mobile phones. After all, modern man There’s definitely a bunch of old unnecessary phones lying around somewhere. Don’t rush to throw them away, it turns out they may still be useful to you.
Necessary materials:
- Cell phone batteries;
- Controller with USB connector;
- A pair of wires;
- Box.
Firstly, it is necessary to clarify that the batteries should be as similar as possible, it will be easier (instead of phone batteries, you can use other lithium-ion batteries). And they all must be the same volume, in our case it is 1020 mAh each.
Their number only affects the volume of the future Power bank, but the optimal range will be from 6000 to 20000 mAh in general. In addition, any of them requires energy for its own operation, so it is necessary to subtract approximately 20-30% from the total power. This will be the pure charge that your external battery can provide.
The connector on the controller can be absolutely anything, exactly what you need. It's just that USB is the most common, so we chose it.
So, when everything is assembled, we can begin assembling our device.
First, let's group the batteries for greater convenience. To do this, install them parallel to each other and fix it all with tape or tape (everything is done taking into account your batteries). Important! Contacts must be open!
Now you need to solder the batteries and the controller together, namely the “+” and “-” contacts (these are the extreme ones). You don't have to touch the central ones. Then, in the “case” of our Power bank, we estimate the location of all the elements and mark the places for future connectors. All that remains is to make holes and fix all the elements with hot glue in the box.
All is ready! This Power bank battery will be enough for you to recharge your phone several times.
Power bank from a regular flashlight
On the market now you can find flashlights that charge other devices, and we will try to do approximately the same thing. Such a device will combine both a flashlight and an external battery.
Necessary materials:
- A simple flashlight;
- Voltage converter with USB connector (5 V);
- Charge controller.
First, let's disassemble the flashlight and take out the resistor from there, the one to which the small LED is soldered. We won't need it anymore (at least here). Instead, we will put a battery charge controller there.
Now, in the place where the flashlight was charged, we put a converter with a USB connector (again, the connector may be the one you need).
Next, you need to solder the “+” and “-” from the flashlight battery to the controller. Now we solder our energy converter and OUT+/OUT contacts on the controller. Don't forget to release the flashlight button and connect it to the energy converter.
After all the work done, we need to check if our device works. If everything is fine, then we attach all the elements using the same hot glue and assemble the installation together.
Now the power bank from the flashlight is ready for use.
These were only the most common and easy-to-manufacture methods for assembling an external battery. There are a huge number of other methods, but they require much more free time, and their cost is much higher. But this does not mean that they are better.
DIY power bank photo
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.
We have to:
- 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
- Let's study the basic circuit of an external battery.
The diagram shows 2 connecting wires 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. It makes sense for iPhone charging. 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.
IMPORTANT. The diode is placed in the direction FROM the solar panel TO the charge board.
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.
Finally
Choose the method that suits you best and build your own portable battery. This thing will definitely come in handy on the road or while traveling. There are a lot of advantages of the device made: it is unique appearance, and also a way to get the power that will satisfy your needs. By using portable battery You can charge not only phones, but also tablets, wireless headphones and other small gadgets.
Solar energy is completely free (for now 🙂), widely available and environmentally friendly form of energy. Many people are familiar with the so-called photovoltaic converters, or solar panels. Their cells are made of special semiconductor materials, and when sunlight hits them, it knocks out electrons, causing them to separate from their atoms. When electrons pass through a cell, they generate electricity.
Power Bank - practice
In general with brief theory finished. And now we will make a powerful and high-quality Power Bank, which collects and stores energy using solar panels, as happens in the previous project. The electricity generated from these panels is stored in a Li-Po battery. Then the rechargeable battery is used to generate the necessary power - stabilized 5 V, which is used in USB gadgets, most often smartphones. The power bank can also be charged from an external 5V source from network adapter at 220 V. Outdoors, it charges itself using sunlight - as intended.
Schematic diagram
Save the diagram to enlarge
Printed circuit board in the archive. The solar cell power bank circuit consists of two parts. The first is a charger based on the MCP73831 and the second is a boost converter based on the LT1302-5, which converts the lithium battery voltage to 5 V.
The MCP73831 is a miniature charge controller for lithium-ion or lithium-polymer batteries. Since the input voltage range is 3.7 - 6 V, any value between these values can be used as an input voltage source. An additional 5 V mini USB input is also included in the circuit to charge the Power Bank from a 220 V network via an adapter when sunlight is not enough. The controller will charge the battery up to 4.2 V fully safe mode. The LED on the controller lights up during the entire charging process.
The second stage is a boost converter that converts the 4V battery voltage to 5V. It is based on the LT1302-5 IC, a DC/DC converter with a fixed output voltage of 5V. The input voltage of the LT1302-5 can be as low as 2.2V.
The solar panels used in the project are rated at 6V and 150mA, which provides about 1Wh under ideal conditions. A lithium polymer battery here there is a power of 3.7 V and 4000 mA, which can give about 15 W/h. Please note that charging will take much longer than 15 hours as storage and boost conversion efficiency will be less than 100%. But since solar energy is free - there is no rush.
A. 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 - time. 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. Information on how to receive cashback (refund) in the amount of 7% of the price of all purchases is on our website. Download the schematic, board and other project files.
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.
Description of the power bank circuit
The powerbank circuit consists of three main parts. This is the charge controller lithium batteries with auto-shut-off 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. We will use a charging board purchased as a charge controller. 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 used metal case, you should additionally insulate the batteries using wide tape.
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 grasses from motherboards. 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 diodes that are in computer units nutrition. Dual to-220 diodes are found in them.
The photo below shows the inverter in assembled condition.
Can be done 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. There are two charges on the controller LED indicator, which show the percentage of charge. 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.
Today you will no longer surprise anyone with the presence of a smartphone, tablet or camera. Every person has all these special gadgets, but quite often situations arise when it is not possible to recharge them using charger via the power grid.
In this case, you will definitely need a power bank or an external battery that is used for recharging portable devices, for example, during hikes. Of course, you can buy a ready-made power bank, but why spend money if you can make it yourself.
We bring to your attention several schemes for constructing a power bank with your own hands.
1. Power bank from mobile phone batteries
So, let's look at how to make a power bank with your own hands using several mobile phone batteries. For this you will need:
Several ordinary mobile batteries (preferably six or nine) with a capacity of 1020 mAh each.
We install the batteries parallel to each other and wrap them lengthwise with tape and across them with electrical tape. Please note that the terminals to which the wires will later be soldered must be open.
We solder ours together rechargeable batteries, connecting two terminals: “plus” and “minus”. The central terminals of the battery or the temperature sensor do not need to be connected, since they are only needed to demonstrate the remaining charge level of this device.
We take control measurements and attach everything with hot glue.
And voila, you're done!
This Power bank will be enough for four to five full charges of your phone.
2. External battery from a simple flashlight
To build a Power bank from a flashlight we will need:
Directly the flashlight itself with a 3.7 Volt battery;
Voltage converter with built-in USB output that allows 3.7 Volts lithium ion battery convert the flashlight to 5 Volts;
Charge controller.
A) Dismantle the device.
B) Remove one of the flashlight resistors (an LED should be soldered to it). This will allow you to replace one of the bright glow modes with a new mode - Power Bank.
C) In the place where the plug for charging the flashlight is located, we place our converter with a USB output.
D) Solder the “plus” and “minus” from the battery to the battery charge controller. Then we solder a 5V converter to the OUT+/OUT- contacts of this controller.
Please note that you must first release one contact of the switch and solder the converter to it.
D) Now we check the functionality of the converter and re-solder it if necessary.
E) So, if everything works, we glue the controller and converter using epoxy glue.
G) We assemble the flashlight and can use it.
Now you will always be in touch and in the light, the main thing is not to forget to charge the flashlight battery!
3. Power bank from simple batteries 2200 mAh 3.6 V
For this Power bank you will need:
The lithium-ion batteries themselves (preferably 8 pieces);
