Do-it-yourself powerful phone charger. Wireless charging for your phone: how to do it yourself
Hello Habra gentlemen and Habra ladies!
I think some of you are familiar with the situation:
“Car, traffic jam, Nth hour behind the wheel. The communicator with the navigator running has been beeping for the third time about the end of the charge, despite the fact that it is always connected to charging. And you, as luck would have it, have absolutely no bearings in this part of the city.”
Next, I will talk about how, with moderately straight hands, a small set of tools and a little money, you can build a universal (suitable for charging with the rated current of both Apple and all other devices) car USB charger for your gadgets.
CAUTION: Under the cut there are a lot of photos, a little work, no LUT and no happy ending (not yet).
Author, why all this?
Some time ago, the story described in the prologue happened to me, a Chinese USB twin absolutely shamelessly let my smart device run out of charge while navigating; out of the declared 500mA, it produced about 350 on both sockets. I must say I was very angry. Well, okay - I’m a fool, I decided, and on the same day, in the evening, I ordered a 2A car charger on eBay, which rested in the depths of the Chinese-Israeli post office. By luck, I had a handkerchief DC-DC step down converter with an output current of up to 3 A lying around and I decided to use it to build myself a reliable and universal car charger.A little about chargers.
I would divide most chargers that are on the market into four types:
1. Apple - tailored for Apple devices, equipped with a little charging trick.
2. Conventional - aimed at most gadgets, for which shorted DATA+ and DATA- are sufficient to consume the rated charging current (the one stated on the charger of your gadget).
3. Clueless - for whom DATA+ and DATA- are hanging in the air. In this regard, your device decides that it is a USB hub or a computer and does not consume more than 500 mA, which negatively affects the charging speed or even the absence of it under load.
4. Cunning%!$&e - since they have a microcontroller installed inside, which tells the device something like what Kipling’s well-known hero told animals - “You and I are of the same blood, you and I”, checks the originality of the charge. For all other devices they are memory devices of the third type.
For obvious reasons, I consider the last two options uninteresting and even harmful, so let’s focus on the first two. Since our charger must be able to charge both Apple and all other gadgets, we use two USB output, one will be focused on Apple devices, the second on all others. I will only note that if you mistakenly connect the gadget to a USB socket that is not intended for it, nothing bad will happen, it will just take the same notorious 500mA.
So, the goal: “With a little work with your hands, get a universal charger for the car.”
What do we need
1. First, let’s look at the charging current, usually it’s 1A for smartphones and about 2 Amps for tablets (by the way, my Nexus 7, for some reason it doesn’t take more than 1.2A from its own charge). In total, to simultaneously charge a medium-sized tablet and smartphone, we need a current of 3A. So the DC-DC converter that I have in stock is quite suitable. I must admit that a 4A or 5A converter would be better suited for these purposes, so that the current would be enough for 2 tablets, but I never found compact and inexpensive solutions, and besides, time was running out.So I used what I had:
Input voltage: 4-35V.
Output voltage: 1.23-30V (adjustable by potentiometer).
Maximum output current: 3A.
Type: Step Down Buck converter.
2. USB socket, I used a double one, which I unsoldered from an old USB hub.
You can also use regular sockets from a USB extension cable.
3. Development board. In order to solder a USB socket to something and assemble a simple charging circuit for Apple.
4. Resistors or resistors, whichever you prefer, and one LED. There are 5 pieces in total, 75 kOhm, 43 kOhm, 2 rated 50 kOhm and one rated at 70 Ohm. The first 4 are exactly where the Apple charging circuit is built; I used 70 Ohms to limit the current on the LED.
5. Body. I found a case for a Mag-Lite flashlight in the bins of my homeland. In general, a black toothbrush case would be ideal, but I couldn’t find one.
6. Soldering iron, rosin, solder, wire cutters, drill and an hour of free time.
Assembling the charger
1. First of all, I short-circuited the DATA+ and DATA- pins on one of the sockets:
*I apologize for the harshness, I got up early and my body wanted to sleep, but my brain wanted to continue the experiment.
This will be our outlet for non-Apple gadgets.
2. We cut off the size of the breadboard we need and mark and drill holes in it for the mounting legs of the USB socket, while simultaneously checking that the contact legs coincide with the holes in the board.
3. Insert the socket, fix it and solder it to the breadboard. We connect the +5V contacts of the first (1) and second (5) sockets to each other, and do the same with the GND contacts (4 and 8).
The photo is for clarification only, the contacts are soldered already on the breadboard
4. Solder the following circuit to the remaining two contacts DATA+ and DATA-:
To maintain polarity, we use the USB pinout:
I got it like this:
Don’t forget to adjust the output voltage; use a screwdriver and a voltmeter to set it to 5 - 5.1V.
I also decided to add an indication to the USB power circuit; in parallel to +5V and GND, I soldered yellow ice with a 70-Ohm resistor to limit the current.
A convincing request to people with a fine mental organization and other lovers of beauty: “Do not look at the following picture, because the soldering is crooked.”
I'm brave!
5. We fix the converter board on our breadboard. I did this using the legs from the same resistors, soldering them into the contact holes on the converter board and on the breadboard.
6. Solder the outputs of the converter to the corresponding inputs on the USB socket. Maintain polarity!
7. Take the case, mark and drill holes for mounting our board, mark and cut out a place for a USB socket and add holes for ventilation opposite the converter chip.
We fasten the breadboard with bolts to the case and get a box like this:
In the Machine it looks like this:
Tests
Next, I decided to check whether my devices would actually consider that they were being charged from their original charger. And at the same time measure the currents.Power is provided by a power supply from an old 24V 3.3A printer.
I measured the current before outputting to USB.
Looking ahead, I’ll say that all the devices I have recognized charging.
I connected to USB socket number one (which is intended for various gadgets):
HTC Sensation, HTC Wildfire S, Nokia E72, Nexus 7, Samsung Galaxy ACE2.
For the Sensation and Nexus 7, I checked the charging time, starting at 1% and charging up to 100%.
The smartphone charged in 1 hour 43 minutes (Anker 1900 mAh battery), I should note that it takes about 2 hours to charge on a standard charge.
The tablet charged in 3 hours 33 minutes, which is half an hour longer than charging from the mains (I only charged one device at a time).
So that both Android devices They took the maximum from the charger, I had to solder a small adapter (which connected to apple USB), the HTC Sensation was connected to it.
I connected the following to USB socket number two: Ipod Nano, Ipod Touch 4G, Iphone 4S, Ipad 2. Since it’s ridiculous to charge the Nano with such a thing, it took a maximum of 200 mA from me, I checked the Touch 4g and iPad. The iPod was charged in 1 hour and 17 minutes from zero to 100% (albeit together with the IPAD 2). The iPad 2 took 4 hours and 46 minutes to charge (one).
As you can see, the iPhone 4S happily consumes its rated current.
By the way, Ipad 2 surprised me; it absolutely did not shy away from a circuit with short-circuited data contacts and consumed exactly the same currents as from the socket intended for it.
Charging process and conclusions
To begin with, let me remind you that all devices that use lithium batteries have a charge controller. It works according to the following scheme:The graph is average and may vary for different devices.
As can be seen from the graph, at the beginning of the charging cycle, the controller allows you to charge with the maximum permissible current for your device and gradually reduces the current. The charge level is determined by voltage; the controllers also monitor the temperature and turn off charging at high temperatures. Charge controllers can be located in the device itself, in the battery or in the charger (very rarely).
You can read more about charging lithium cells.
Actually, here we come to the point why this topic is called: “Attempt number one.” The fact is that the maximum that I was able to squeeze out of charging is: 1.77A
Well, the reason, in my opinion, is not the optimally selected inductor, which in turn does not allow the Buck converter to produce its maximum current. I thought about replacing it, but I don’t have a tool for SMD soldering and don’t have any plans to do so in the near future. This is not a mistake of the designers of the board from ebay, it is simply a feature of this circuit since it is oriented to different incoming and outgoing voltages. Under such conditions, it is simply impossible to produce the maximum current over the entire voltage range.
As a result, I got a device that is capable of charging two smartphones at the same time or one tablet in a car in a reasonable amount of time.
In connection with the above, it was decided to leave this charger as is and assemble a new one, entirely with our own hands, based on a more powerful LM2678 converter,
which in the future will be able to “feed” two tablets and a smartphone at the same time (5A output). But more on that next time!
P.S.:
1. The text may contain punctuation, grammatical and semantic errors, please report them in a personal message.
2. Thoughts, ideas, technical corrections and control points from more experienced comrades are, on the contrary, welcome in the comments.
3. I apologize for any technical inaccuracies, because... Until recently, I was not involved in electronics and circuit design.
Thank you for your attention, good luck and inexhaustible optimism to everyone!
IN Lately became very popular portable chargers for mobile phones or otherwise they are called Power Bank. They are sold in many stores, and we can buy them without any problems, but I think many radio amateurs are much more interested make your own portable charger for your mobile phone. This article will show you a simple scheme charger powered by AA batteries.
Almost all devices that are recharged via a computer’s USB, such as mobile phones, MP3 players, cameras and much more, can be charged using regular 1.5 volt AA batteries; if desired, they can be replaced with rechargeable batteries.
Experimental model of a portable charger with surge protection:
The diagram according to which you need to assemble the charger:
Since the circuit uses discrete components, a surge protection system has been included in case any element fails. How the scheme works will be described below.
The main component of the circuit is chip 7805, which is a 5-volt voltage regulator with a maximum output current of 1.5 amperes. Therefore, this charger will supply a maximum of 1.5 A to charge your mobile.
Let's make a small digression from the topic. Recently I encountered a problem: I needed to help relatives from Germany obtain a visa, the queues at the embassy turned out to be a couple of months ahead and then I came across the website http://www.visardo.ru/ where the visa was issued in just a week.
The zener diode in the circuit provides an output voltage of no more than 5.6 volts, and if the output voltage exceeds 5.6 volts, it automatically protection will work turning off the power to the 7805 chip.
For reliability, you can install a 2A fuse in front of the microcircuit to be more sure that the charger will turn off when an overvoltage occurs.
The output of 7805 is connected to a female USB from which you will charge your gadget. In this circuit we used four AA batteries of 1.5V and 1.5A.
Well, yes, perhaps this charger will be larger than those sold in stores and batteries will be required for it, but as I said at the beginning, much it's more interesting to do something with your own hands than just buy.
One of the most important problems modern man Having a smartphone is a constant drain on the device's battery. Portable chargers have been created especially for such cases, which allow you to connect your gadget using a USB cable and charge your smartphone using the battery built into the charger.
So, to make a portable charger we need:
- Two crown batteries (one of the batteries can be used),
- Box (you can use a metal candy box),
- A switch that can be removed from an old cassette player or a broken children's toy
- And most importantly, a USB charger for the car, which can be purchased for about 2-3 dollars,
- And also the copper wires with which we will connect everything.
First of all, we must make a removable brand for the battery. If you have old toys or devices at home that use Krona batteries, then ready-made stamps can be removed from them. If there are no such toys or devices, then you can make a brand yourself. To do this, you need to remove the top part of the crown battery, spread flux on the metal contacts on the inside and solder the copper wires to them. For fixation and insulation, you can use regular hot melt adhesive.
The stamps are ready, they can be attached to the contacts of the second battery (wide contact to narrow, and narrow to wide).
The next thing we need to do is disassemble the car charger by taking the board on which the USB connector is located. All that remains is to assemble all the components of our portable charger and connect everything through the switch.
When connecting the mark to the battery, you can see which wire is positive and which is negative if you use different colored wires. If not, then you can mark it as a plus for greater convenience and ease.
The central wire or spring on a car charger is always positive, and the wire located on the side is always negative. So, we must connect the positive wire of our battery to the switch, and the negative wire directly to the charger board.
If the positive wire on the charger is made in the form of a spring, it can be replaced with a regular one for greater convenience.
After this, two positive wires need to be soldered to two contacts on the fork.
The device is almost ready. All that remains is to assemble it in a box, on which in the side you need to cut two passages for a USB input and a switch.
The number of mobile communications devices in active use is constantly growing. Each of them comes with a charger supplied in the kit. However, not all products meet the deadlines set by the manufacturers. The main reasons are the low quality of electrical networks and the devices themselves. They often break down and it is not always possible to quickly purchase a replacement. In such cases, you need a circuit diagram for a phone charger, using which it is quite possible to repair a faulty device or make a new one yourself.
Main faults of chargers
The charger is considered the weakest link in mobile phones. They often fail due to poor quality parts, unstable mains voltage or as a result of ordinary mechanical damage.
The simplest and best option is to purchase a new device. Despite the differences in manufacturers, the general schemes are very similar to each other. At its core, this is a standard blocking generator that rectifies the current using a transformer. Chargers may differ in connector configuration, they may have different circuits of input network rectifiers, made in a bridge or half-wave version. There are differences in small things that are not of decisive importance.
As practice shows, the main faults of the memory are the following:
- Breakdown of the capacitor installed behind the mains rectifier. As a result of the breakdown, not only the rectifier itself is damaged, but also a constant resistor with low resistance, which simply burns out. In such situations, the resistor practically acts as a fuse.
- Transistor failure. As a rule, many circuits use high-voltage high-power elements marked 13001 or 13003. For repairs, you can use the domestically produced KT940A product.
- Generation does not start due to a breakdown of the capacitor. The output voltage becomes unstable when the zener diode is damaged.
Almost all charger housings are non-separable. Therefore, in many cases, repairs become impractical and ineffective. It’s much easier to use a ready-made source direct current, connecting it to the required cable and adding the missing elements.
Simple electronic circuit
The basis of many modern chargers are the simplest pulse circuits blocking generators containing only one high-voltage transistor. They are compact in size and capable of delivering the required power. These devices are completely safe to use, since any malfunction leads to a complete absence of voltage at the output. This prevents high unstabilized voltage from entering the load.
The rectification of the alternating voltage of the network is carried out by the diode VD1. Some circuits include an entire diode bridge of 4 elements. The current pulse is limited at the moment of switching on by resistor R1 with a power of 0.25 W. In case of overload, it simply burns out, protecting the entire circuit from failure.
To assemble the converter, a conventional flyback circuit based on transistor VT1 is used. More stable operation is ensured by resistor R2, which starts generation at the moment of power supply. Additional generation support comes from capacitor C1. Resistor R3 limits the base current during overloads and power surges.
High reliability circuit
In this case, the input voltage is rectified by using a diode bridge VD1, a capacitor C1 and a resistor with a power of at least 0.5 W. Otherwise, while charging the capacitor when turning on the device, it may burn out.
Capacitor C1 must have a capacity in microfarads equal to the power of the entire charger in watts. The basic circuit of the converter is the same as in the previous version, with transistor VT1. To limit the current, an emitter with a current sensor based on resistor R4, diode VD3 and transistor VT2 is used.
This phone charger circuit is not much more complicated than the previous one, but much more efficient. The inverter can operate stably without any restrictions despite short circuits and loads. Transistor VT1 is protected from emissions of self-induction EMF by a special chain consisting of elements VD4, C5, R6.
It is necessary to install only a high-frequency diode, otherwise the circuit will not work at all. This chain can be installed in any similar circuits. Due to this, the housing of the switch transistor heats up much less, and the service life of the entire converter increases significantly.
The output voltage is stabilized by a special element - a zener diode DA1, installed at the charging output. Optocoupler V01 is used.
DIY charger repair
With some knowledge of electrical engineering and practical skills in working with tools, you can try to repair a cell phone charger on your own.
First of all, you need to open the charger case. If it is dismountable, you will need an appropriate screwdriver. With the non-separable option, you will have to use sharp objects, separating the charge along the line where the halves meet. As a rule, a non-separable design indicates low quality chargers.
After disassembly, a visual inspection of the board is carried out in order to detect defects. Most often, faulty areas are marked with traces of burning resistors, and the board itself will be darker at these points. Mechanical damage is indicated by cracks in the case and even on the board itself, as well as bent contacts. It is enough to bend them back into place towards the board to resume the supply of mains voltage.
Often the cord at the output of the device is broken. Breaks most often occur near the base or directly at the plug. The defect is detected by measuring resistance.
If there is no visible damage, the transistor is desoldered and ringed. Instead of a faulty element, parts from burnt-out energy-saving lamps are suitable. Everything else was done - resistors, diodes and capacitors - are checked in the same way and, if necessary, replaced with serviceable ones.
Making your own solar USB charger for your phone is one of the most interesting and useful projects on. Making a homemade charger is not too difficult - the necessary components are not very expensive and are easy to obtain. Solar USB chargers are ideal for charging small devices such as a phone.
The weak point of all homemade solar chargers is the batteries. Most are assembled on the basis of standard nickel-metal hydride batteries - cheap, accessible and safe to use. But unfortunately, NiMH batteries have too low voltage and capacity to be seriously considered in quality, the energy consumption of which is only growing every year.
For example, the iPhone 4's 2000 mAh battery can still be fully recharged from a homemade solar charger with two or four AA batteries, but the iPad 2 is equipped with a 6000 mAh battery, which is no longer so easy to recharge using a similar charger.
The solution to this problem is to replace nickel-metal hydride batteries with lithium ones.
From this instruction you will learn how to make a solar USB charger with a lithium battery with your own hands. Firstly, compared to this, a homemade charger will cost you very little. Secondly, it is very easy to assemble. And most importantly, this lithium USB charger is safe to use.
Step 1: Required components to assemble the solar USB charger.
Electronic components:
- 5V or higher solar cell
- 3.7V Li-ion battery
- Li-ion battery charging controller
- USB DC boost circuit
- Panel mount 2.5mm jack
- 2.5 mm jack with wire
- Diode 1N4001
- The wire
Construction materials:
- Insulating tape
- Heat shrink tubing
- Double Sided Foam Tape
- Solder
- Tin box (or other enclosure)
Tools:
- Soldering iron
- Hot glue gun
- Drill
- Dremel (not required, but recommended)
- Wire cutters
- Wire stripper
- Help from a friend
This tutorial shows you how to make a solar powered phone charger. You can refuse to use solar panels and limit yourself to making a regular USB charger using lithium-ion batteries.
Most of the components for this project can be purchased at online electronics stores, but the USB DC boost circuit and lithium-ion battery charge controller will not be so easy to find. Later in this guide, I'll tell you where you can get most of the required components and what each of them does. Based on this, you can decide for yourself which option suits you best.
Step 2: Benefits of lithium battery chargers.
You may not realize it, but most likely a lithium-ion battery is in your pocket or on your desk right now, or maybe in your wallet or... Most modern electronic devices use lithium-ion batteries, characterized by high capacity and voltage. They can be recharged many times. Most AA batteries are nickel-metal hydride in chemical composition and cannot boast of high technical characteristics.
From a chemical point of view, the difference between a standard AA NiMH battery and a Li-ion battery is chemical elements contained inside the battery. If you look at the periodic table of elements, you will see that lithium is in the left corner next to the most reactive elements. But nickel is located in the middle of the table next to chemically inactive elements. Lithium is so reactive because it only has one valence electron.
And it is precisely for this reason that there are many complaints about lithium - sometimes it can get out of control due to its high chemical reactivity. Several years ago, Sony, a leader in laptop battery production, produced a batch of low-quality laptop batteries, some of which spontaneously caught fire.
This is why when working with lithium-ion batteries, we must take certain precautions - very accurately maintain the voltage during charging. This instruction uses 3.7 V batteries which require a charging voltage of 4.2 V. If this voltage is exceeded or decreased chemical reaction can get out of control with all the ensuing consequences.
This is why extreme caution must be exercised when handling lithium batteries. If you handle them carefully, they are quite safe. But if you do inappropriate things with them, it can lead to big trouble. Therefore, they should be used only strictly according to the instructions.
Step 3: Selecting a lithium-ion battery charge controller.
Due to the high chemical reactivity of lithium batteries, you must be one hundred percent sure that the charge voltage control circuit will not let you down.
Although you can make your own voltage control circuit, it is better to simply buy a ready-made circuit that you will be confident in its performance. There are several charge control schemes available to choose from.
On this moment Adafruit is now in its second generation of charge controllers for lithium batteries with several available input voltages. These are pretty good controllers, but they are too large. It is unlikely that it will be possible to assemble a compact charger using them.
You can buy small lithium battery charging controller modules on the Internet, which are used in this manual. Based on these controllers, I also assembled many others. I like them for their compactness, simplicity and LED battery charge indicator. As with Adafruit, when there is no sun, the lithium battery can be charged via the controller's USB port. The ability to charge via a USB port is an extremely useful option for any solar charger.
Regardless of which controller you choose, you should know how it works and how to operate it correctly.
Step 4: USB port.
Most modern devices can be charged via the USB port. This is the standard all over the world. Why not just connect the USB port directly to the battery? Why do you need a special circuit for charging via USB?
The problem is that the USB voltage is 5V, but the lithium-ion batteries we will be using in this project are only 3.7V. So we will have to use a USB DC boost circuit that increases the voltage to sufficient to charge various devices. Most commercial and homemade USB chargers, on the contrary, use step-down circuits, since they are assembled on the basis of 6 and 9 V batteries. Step-down circuits are more complex, so it is better not to use them in solar chargers.
The scheme used in this manual was chosen as a result of lengthy testing of various options. It's almost identical to Adafruit's Miniboost circuit, but costs less.
Of course you can buy an inexpensive USB charger online and take it apart, but we need a circuit that converts 3V (the voltage of two AA batteries) to 5V (the voltage on the USB). Disassembling a regular or car USB charger will not do anything, since their circuits work to reduce the voltage, but on the contrary, we need to increase the voltage.
In addition, it should be noted that the Mintyboost circuit and the circuit used in the project are capable of working with Apple gadgets, unlike most other USB charging devices. Apple devices check the information pins on the USB to know where they are connected. If the Apple gadget determines that the information pins do not work, then it will refuse to charge. Most other gadgets do not have such a check. Believe me - I tried many cheap charging circuits from eBay - none of them managed to charge my iPhone. You don’t want your homemade USB charger to be unable to charge Apple gadgets.
Step 5: Battery selection.
If you Google a little, you will find a huge variety of sizes, capacities, voltages and prices. At first, it will be easy to get confused in all this diversity.
For our charger we will be using a 3.7V lithium polymer (Li-Po) battery, which is very similar to an iPod or cell phone battery. Indeed, we only need a 3.7 V battery, since the charging circuit is designed for this voltage.
The fact that the battery should be equipped with built-in protection against overcharge and overdischarge is not even discussed. This protection is usually called "PCB protection". Search eBay for these keywords. It is just a small printed circuit board with a chip that protects the battery from overcharging and discharging.
When choosing a lithium-ion battery, look not only at its capacity, but also at its physical size, which mainly depends on the case you choose. I used an Altoids tin box as the case, so I was limited in my choice of battery. At first I thought of buying a 4400 mAh battery, but because of it large sizes I had to limit myself to a 2000 mAh battery.
Step 6: Connecting the solar panel.
If you are not going to make a charger that can be recharged from the sun, you can skip this step.
This tutorial uses a 5.5V, 320mA hard plastic solar cell. Any large solar panel will work for you. For the charger, it is best to choose a battery designed for a voltage of 5 - 6 V.
Take the wire by the end, divide it into two parts and strip the ends a little. A wire with a white stripe is negative, and an all-black wire is positive.
Solder the wires to the corresponding contacts on the back of the solar panel.
Cover the solder joints with electrical tape or hot glue. This will protect them and help reduce stress on the wires.
Step 7: Drill the tin box or housing.
Since I used an Altoids tin as the body, I had to do a little drill work. In addition to the drill, we will also need a tool such as a dremel.
Before you start working with a tin box, put all the components in it to make sure in practice that it suits you. Think about how best to place the components in it, and only then drill. You can mark the locations of the components with a marker.
After designating the places, you can get to work.
There are several ways to remove the USB port: make a small cut right at the top of the box, or drill a hole of the appropriate size on the side of the box. I decided to make a hole on the side.
First, attach the USB port to the box and mark its location. Drill two or more holes inside the designated area.
Sand the hole with the Dremel. Be sure to follow safety precautions to avoid injuring your fingers. Do not hold the box in your hands under any circumstances - clamp it in a vice.
Drill a 2.5mm hole for the USB port. If necessary, widen it using a Dremel. If you don't plan to install a solar panel, then the 2.5mm hole is not necessary!
Step 8: Connecting the charging controller.
One of the reasons I chose this compact charge controller is its reliability. It has four contact pads: two in front next to the mini-USB port, where constant voltage is supplied (in our case from solar panels), and two in the back for the battery.
To connect a 2.5 mm connector to the charging controller, you need to solder two wires and a diode from the connector to the controller. In addition, it is advisable to use heat-shrinkable tubing.
Fix the 1N4001 diode, charge controller and 2.5mm jack. Place the connector in front of you. If you look at it from left to right, the left contact will be negative, the middle one will be positive, and the right one is not used at all.
Solder one end of the wire to the negative leg of the connector, and the other to the negative pin on the board. In addition, it is advisable to use heat-shrinkable tubing.
Solder another wire to the diode leg, next to which there is a mark. Solder it as close to the base of the diode as possible to save more space. Solder the other side of the diode (without the mark) to the middle pin of the connector. Again, try to solder as close to the base of the diode as possible. Finally, solder the wires to the positive contact on the board. In addition, it is advisable to use heat-shrinkable tubing.
Step 9: Connecting the battery and USB circuit.
At this stage, you only need to solder four additional contacts.
You need to connect the battery and USB circuit to the charge controller board.
First cut some wires. Solder them to the positive and negative pins on the USB circuit, which are located on the bottom of the board.
After that, connect these wires together with the wires coming from the lithium-ion battery. Make sure you connect the negative wires together and connect the positive wires together. Let me remind you that the red wires are positive and the black wires are negative.
Once you have twisted the wires together, weld them to the terminals on the battery that are on back side charging controller boards. Before soldering, it is advisable to thread the wires into the holes.
Now we can congratulate you - you have 100% completed the electrical part of this project and can relax a little.
At this stage, it is a good idea to check the functionality of the circuit. Since all electrical components are connected, everything should work. Try charging your iPod or any other gadget equipped with a USB port. The device will not charge if the battery is low or defective. In addition, place the charger in the sun and see if the battery will charge from the solar panel - the small red LED on the charge controller board should light up. You can also charge the battery via a mini-USB cable.
Step 10: Electrically isolate all components.
Before placing all the electronic components in the tin box, we must be sure that it cannot cause a short circuit. If you have a plastic or wooden case, then skip this step.
Place several strips of electrical tape on the bottom and sides of the tin box. It is in these places that the USB circuit and charging controller will be located. The photographs show that my charging controller was left loose.
Try to carefully insulate everything so that a short circuit does not occur. Make sure the solder joints are secure before applying hot glue or tape.
Step 11: Placing the Electronic Components in the Case.
Since the 2.5mm jack needs to be secured with bolts, place it first.
My USB circuit had a switch on the side. If you have the same circuit, then first check whether the switch that is needed to turn the “charging mode” on and off works.
Finally, you need to secure the battery. For this purpose, it is better to use not hot glue, but several pieces of double-sided tape or electrical tape.
Step 12: Operate your homemade solar charger.
Finally, let's talk about correct operation homemade USB charging.
You can charge the battery via a mini-USB port or from the sun. The red LED on the charge controller board indicates the charging process, and the blue LED indicates a fully charged battery.