For some reason, phone manufacturers do not want to release normal self-charging gadgets. The picture above is the Samsung E1107 phone. According to the manufacturer, under ideal conditions it can be fully charged from the sun in 55 hours. But there are no such ideal conditions in Moscow.

There are more efficient solar panels and lower consumption phones. For example, with a black and white small screen Alcatel ot-117. I have matured the desire to try to make a solar panel for the phone myself and place it on the back side, on the battery cover.

I have a good old friend Alcatel ot-117:

Finding a solar panel at a reasonable price with normal efficiency turned out to be unrealistic in Moscow. I bought a Chinese charger.

I bought this charger based on the characteristics. The manufacturer promised a full charge in 14-16 hours under the sun of the built-in 500 mAh battery, i.e. like on my phone. This was fine for me, since the phone discharges in 4 days and the power of the solar panel, even taking into account not ideal conditions, should be enough so that the phone does not need to be charged from standard charging generally... And all this miracle costs 150 rubles on aliexpress. Cheaper than buying a solar panel separately in our stores. Moreover, this solar panel is quite efficient.

And so experiment

Had to cut the NOKIA microusb cable:

Got microusb on one side and 4 wires on the other:

The solar battery needs to be connected with a red wire with a red (plus with a plus), and the second solar battery wire (I have a blue one) with a (-) sign with a black wire. Also, to start charging, you need to close the white and green wires. Wiring diagram:

Received this sample for experiments:

It turned out that the phone charges from it, lying on my office desk in sunny weather in 2 working days, and in cloudy weather - in 3 working days. I work from 8 am to 5 pm. The office windows face east. I consider the experiment to be successful. All that remains is to solder everything under the case directly to the microusb connector and place it in the cover from the battery compartment. There is no need for any additions in the form of diodes and other radio components, since there is no self-discharge when connected to the microusb connector of the phone, and the phone is charged naturally. The charging process is displayed on the phone screen. It's amazing how easy things are.

To help I spread the microusb pinout figure:

This is what the assembly looks like:

The solar panel will be attached with double-sided soft tape:

I ordered a more powerful solar panel from ebee. I also plan to connect it via an SS14 diode (costs 5 rubles) directly to the battery contacts without soldering, simply by holding the contacts. Later I will lay out the connection diagram. The panel will have to wait 3 weeks. It is 2 times more effective than this one and costs only 100 rubles. I decided to do this because of the constant appearance of an annoying message about connecting and disconnecting charging.

Features:
Max. power: 0.5W.
Max. current: 100mA.
Max. voltage: 5V.
Size: 8.6cm x 3.8cm x 0.2cm.

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 like your phone.

The weak point of all homemade solar chargers is the batteries. Most solar chargers are built with standard NiMH batteries - cheap, affordable and safe to operate. But unfortunately, NiMH batteries have too low voltage and capacity to be seriously considered as chargers for modern gadgets, the power consumption of which only grows 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 has a 6000 mAh battery that is no longer easy to recharge with a similar charger.

The solution to this problem is to replace nickel-metal hydride batteries with lithium ones.

In this tutorial, you will learn how to make a solar USB charger with a lithium battery with your own hands. Firstly, compared to commercial chargers, this homemade charger will cost you very little. Secondly, it is very easy to assemble it. And most importantly, this lithium USB charger is safe to use.

Step 1: Required components for solar USB charger assembly.

Electronic components:

• Solar cell 5V or higher
• 3.7V Li-ion battery
• Li-ion battery charging controller
• DC USB Boost Circuit
• 2.5mm Panel Mount Connector
• 2.5mm plug 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 (optional, but desirable)
• Nippers
• Wire stripper
• Friend's help
• Protective glasses

This guide will show you how to make a solar phone charger. You can refuse to use solar panels and limit yourself only to the manufacture of a conventional USB charger on lithium-ion batteries.

Most of the components for this project can be purchased from online electronics stores, but the USB DC step-up circuit and lithium-ion battery charge controller will not be easy to find. Later in this guide, I'll show you where you can get most of the required components and what each one is for. Based on this, you yourself decide which option suits you best.

Step 2: Benefits of Lithium Battery Chargers.

You may not guess, but most likely the lithium-ion battery is right now in your pocket or on your desk, or maybe in your wallet or backpack. Most modern electronic devices use lithium-ion batteries, which are characterized by a large capacity and voltage. They can be recharged many times. Most AA batteries are nickel-metal hydride in terms of 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 lithium ion battery lies in the chemical elements contained within the battery. If you look at the periodic table of elements of Mendeleev, you will see that lithium is in the left corner next to the most reactive elements. Nickel, on the other hand, 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 activity. A few years ago, Sony, a leader in laptop batteries, manufactured a batch of low-quality laptop batteries, some of which spontaneously burst into flames.

That is why, when working with lithium-ion batteries, we must adhere to certain precautions - very accurately maintain the voltage during charging. This manual uses 3.7 V batteries, which require a charging voltage of 4.2 V. If this voltage is exceeded or decreased, a chemical reaction can get out of control with all the ensuing consequences.

This is why extreme care must be taken when working with lithium batteries. If handled with care, they are reasonably safe. But if you do the inappropriate things with them, it can lead to big trouble. Therefore, they should only be operated 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 100% sure that the charge voltage control circuit will not let you down.

Although you can make your own voltage control circuit, it's best to just buy a ready-made circuit that you can be sure of working. Several charge control schemes are available to choose from.

Adafruit is currently launching the second generation of lithium battery charge controllers with several available input voltages. These are pretty good controllers, but they are too big. It is unlikely that on their basis it will be possible to assemble a compact charger.

You can buy small lithium battery charging controller modules on the Internet, which are used in this manual. Based on these controllers, I also collected many other homemade products. I like them for their compactness, simplicity and the presence of an LED indication of the battery charge. As with the Adafruit, the lithium battery can be charged via the controller's USB port when the sun is out. USB charging is an extremely useful option for any solar charger.

Regardless of which controller you choose, you must know how it works and how to properly operate it.

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 plug the USB port directly into the battery? Why do you need a dedicated USB charging circuit?

The problem is that according to the USB standard, the voltage is 5V, and the lithium-ion batteries that we will use in this project are only 3.7V. Therefore, we will have to use a USB DC boost circuit that increases the voltage to enough 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. Lower-voltage circuits are more complex, so it is better not to use them in solar chargers.

The circuit used in this manual was selected as a result of extensive testing of various options. It is almost identical to the Minityboost Adafruit scheme, but costs less.

Of course you can buy an inexpensive USB charger online and disassemble it, but we need a circuit that converts 3V (voltage of two AA batteries) to 5V (voltage on USB). Disassembling a regular or car USB charging will not work, since their circuits work to lower 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 chargers. Apple devices check USB info pins to know where they are connected. If the Apple gadget determines that the info pins are not working, then it will refuse to charge. Most other gadgets do not have this check. Trust me - I've tried a lot of cheap charging schemes from eBay - none of them have been able 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 selection of batteries of different sizes, capacities, voltages and costs. 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 mobile phone battery. Indeed, we need a battery exclusively for 3.7 V, since the charging circuit is designed specifically for this voltage.

The fact that the battery should be equipped with built-in protection against overcharge and over discharge is not even discussed. This protection is commonly referred to as "PCB protection". Search for these keywords on the eBay online auction site. From itself 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 had an Altoids tin box as the case, so I was limited in the choice of the battery. At first I thought to buy a 4400 mAh battery, but due to its large size I had to limit myself to a 2000 mAh battery.

Step 6: Connect the solar panel.

If you are not going to make a solar charger, you can skip this step.

This tutorial uses a 5.5V 320mA solar cell in a hard plastic case. Any large solar panel will do. For the charger, it is best to choose a battery rated for 5 - 6 V.

Take the end of the wire, split it in two and strip the ends a little. The wire with the white stripe is negative, and the completely black wire is positive.

Solder the wires to the corresponding pins on the back of the solar panel.

Cover the solder joints with tape or hot glue. This will protect them and help reduce stress on the wires.

Step 7: Drill a tin box or case.

Since I used an Altoids tin box for the case, I had to do a bit of work with a drill. In addition to a drill, we also need a tool such as a dremel.

Before you start working with the tin box, fold all the components into it to make sure in practice that it suits you. Think about how best to place the components in it, and only then drill. The locations of the components can be marked with a marker.

After the designation of 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 in the side.

First, attach the USB port to the box and mark its location. Drill two or more holes within the designated area.

Grind the hole with a dremel. Be sure to follow safety precautions so as not to injure your fingers. Do not hold the box in your hands under any circumstances - grip it in a vice.

Drill a 2.5mm hole for the USB port. Expand it with a dremel if necessary. If you don't plan on installing a solar panel, then there is no need for a 2.5mm hole!

Step 8: Connect the charging controller.

One of the reasons I chose this compact charging controller is its high reliability. It has four contact pads: two in the front next to the mini-USB port, where DC voltage is supplied (in our case, from solar panels), and two in the back for the battery.

To connect the 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 shrink tubing.

Fix the 1N4001 diode, charge controller and 2.5mm connector. 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 wiring to the negative leg of the connector, and the other to the negative terminal on the board. In addition, it is advisable to use heat shrink tubing.

Solder one more wire to the leg of the diode, next to which the mark is applied. Solder it as close to the base of the diode as possible to save more space. Solder the other side of the diode (unmarked) to the middle leg of the connector. Again, try to solder as close to the base of the diode as possible. Finally, solder the wires to the positive terminal on the board. In addition, it is advisable to use heat shrink tubing.

Step 9: Connect 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.

Cut some wires first. Solder them to the positive and negative pins on the USB circuit, which are located on the underside of the board.

Then connect these wires together with the wires coming from the lithium-ion battery. Make sure to connect the negative wires together and connect the positive wires together. Let me remind you that the red wires are positive, and the black ones are negative.

Once you've twisted the wires together, weld them to the contacts on the battery, which are on the back of the charge controller board. Before soldering the wiring, it is advisable to thread it through the holes.

Now we can congratulate you - you have 100% completed the electrical part of this project and you can relax a little.

At this point, it is a good idea to test that the circuit is working. Since all the electrical components are connected, everything should work. Try charging your iPod or any other gadget with a USB port. The device will not charge if the battery is low or defective. Also, place the charger in the sun and see if the battery is charging from the solar panel - this should illuminate the small red LED on the charge controller board. You can also charge the battery via a mini-USB cable.

Step 10: Electrical isolation of 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 a few strips of duct 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 the charging controller was left loose.

Try to insulate everything thoroughly so that a short circuit does not occur. Make sure the solder is strong before applying hot glue or tape.

Step 11: Place the electronic components in the housing.

Since the 2.5mm connector needs to be bolted in, place it first.

My USB circuit had a switch on the side. If you have the same circuit, then first check if the switch that is needed to turn on and off the "charging mode" works.

Finally, you need to secure the battery. For this purpose, it is better to use not hot glue, but a few pieces of double-sided tape or electrical tape.

Step 12: Operate your homemade solar charger.

In conclusion, let's talk about the correct operation of a homemade USB charger.

The battery can be charged via the mini-USB port or from the sun. A red LED on the charge controller board indicates charging, and a blue LED indicates a fully charged battery.

On my last hike, I managed to charge my iPhone 4 almost 80% on the plane, considering that I was listening to music. The battery capacity was 2000 mAh. It will take much longer to charge the 4400 or 6600 mAh batteries. This is especially true for iPods and other tablets.

Although this is a rather complicated instruction, I hope you managed to assemble your own USB charger with a lithium-ion battery. Considering that prices for lithium batteries and controllers for them are falling, there is no point in doing homemade charging on other types of batteries. Lithium-ion batteries are especially well suited for projects where size is critical. Nowadays, you can buy lithium-ion batteries in even the most insanely small sizes. It is the best source of energy for autonomous hiking.

The approaching May holidays and summer holidays means that soon we will be spending a lot of time outdoors: going on picnics, going to the country house and hiking. To prevent your smartphone from being discharged at the most inopportune moment and you do not depend on a portable battery, you can charge your smartphone with solar batteries. It's easy, fast and very cheap. In addition, you can always involve a child in working on this device - show him the basics of soldering and connecting power circuits, as well as talk about the work of solar panels and environmentally friendly methods of generating energy. If you have the necessary parts and tools, the work itself takes no more than five minutes, and in terms of component costs, you will keep within about 200 rubles.

Tools and materials

Compact solar panel (6V) - about 70 rubles.
- USB charger circuit (5V) - about 100 rubles.
- Wire for connecting components
- Plastic card for stand
- Smartphone and cable for testing
- Glue gun
- Soldering iron
- Multitool

There are five easy steps to follow

1. Cut the wires so long that it is convenient to use them to connect the panel to the charger circuit.

2. Solder the wires to the solar panel and connect them to the charger, observing the polarity

3. Use a glue gun to attach the charger to the panel and make sure the outline of the USB port does not touch the wires

4. Bend the plastic card and stick it to the inside of the panel for future use as a stand

5. Connect your smartphone and check if the charger is working.

How to make a solar charger for your phone with your own hands?

We received a lot of questions about how you can make a solar charger for your phone with your own hands. This is a popular question among users, since many leave in the summer for a summer residence or just for a vacation in nature, where there is no household electrical network. Therefore, the problem of charging the phone becomes acute. You can assemble a simple device that will charge your smartphone from a solar panel. But for its successful work, you will need to fulfill certain requirements. In this short post, we will try to present a solution to this problem.

First, let's list what we need.

• Photocell;
• Charge controller for lithium batteries with USB output;
• Give a piece of wires 10-15 centimeters long;
• Soldering iron, rosin, solder;
• Silicone or glue.

Questions may arise from the photocell (solar panel) and the charge controller. As for the first, it is better to take a ready-made photocell with soldered wires. Even if it will cost more than wirelessly, it is better to take a ready-made one.

Now for the electrical characteristics of the solar panel. Some people use solar panels from garden lights with photocells. It should be said right away that this is an unfortunate decision. Such panels have very low power. Their size is about 7 by 7 centimeters and they give out output voltages up to 3.5 volts. And this is at its peak on a sunny day. In this case, you will have to use an additional step-up circuit, since the phone battery must be charged when 5 volts are applied. And such a scheme is additional losses.

As a result, the current to the phone battery is sold very small and the percentage of charging is greatly delayed. Models with a voltage of 5 volts and a power of 0.8 watts cost about 350-400 rubles. They are capable of charging the phone with a current of 150-200 milliamperes. With these parameters, charging will also not be fast, but it is still better than using sockets from garden lamps.

If you take a solar photocell with an output voltage of more than 5 volts, then you will have to additionally install a step-down circuit. So look for a 5 volt solar panel right away.

Now on the charge controller. There are many of them for sale on the Internet. The image below shows a typical version.

The board has two pads for soldering wires from the solar panel, as well as a USB port for connecting to a phone. The price of the issue on Aliexpress is about 100 rubles. There are also options as in the following image.

Such controllers also have contact pads BAT + and BAT-, to which a lithium battery is connected. This can come in handy if you are going to make a full-fledged Power Bank. In our case, you need to charge the phone via the USB interface and this option will be superfluous.

After the components are selected, nothing remains. The pins from the solar panel are soldered to the input pads of the charge controller board, observing the polarity. The photocell is installed so that sunlight falls on it as much as possible. Then the phone is connected via a USB cable and charging is on. However, you shouldn't expect fast charging. With a current of 150-200 mA, charging will take quite a long time. To shorten the process time, you need a charging current of at least 0.5 ampere, and even better 1 ampere.

P.S. There is also the option of charging the phone directly from the solar panel without a controller. In this case, the wires from the photocell, observing the polarity, are connected to the corresponding terminals of the USB cable, which will be connected to the phone. In this case, a Schottky diode is inserted into the gap in the negative wire so that the battery does not discharge. To be honest, not a very elegant option.

If the article turned out to be useful to you, spread the link to it on social networks. This will help the development of the site. Vote in the poll below and rate the material! Leave corrections and additions to the article in the comments.

The author came up with the idea to create a solar charger for my phone. Usually, in order to charge a mobile phone, a constant voltage of 5 V is required. The voltage generated by solar panels is not constant and depends largely on the lighting conditions. Looking for a way out of this situation, the author drew attention to the KR142EN5A voltage stabilizer, which will allow the phone's battery to be powered from the energy supplied by the solar battery.

Materials needed to create a solar charger:

1) solar panels with a voltage of 3V 2 pieces
2) a 5 V voltage regulator, in this case the KR142EN5A microcircuit
3) USB connector for phone power cable
4) wires
5) solder
6) hot melt glue
7) soldering iron

Consider the main points of creating this device.

The KR142EN5A stabilizer is a foreign analogue of the L7805CV, you can order them via the Internet or look at the radio parts store in your city. The main advantage of such a stabilizer is that when a voltage from 5 V to 15 V is applied to the input, it outputs stable 5 V.

This, in turn, means the possibility of using a solar panel with a generated voltage from 5 V to 15 V, corresponding to the range of the stabilizer.

However, this circuit also has a drawback, which is that if the supplied voltage from the solar battery is less than 5 V, then the device will not charge the phone battery.

In addition to this stabilizer, a solar battery, USB connector, wires and other minor things were also purchased.
After all the necessary elements were prepared, the author proceeded to assemble the components of the charger.

Below you can see an example diagram of a solar battery charger:

The author had two solar panels with an operating voltage of 3 V. Since the device requires a voltage of at least 5 V to operate, the author simply connected these two batteries in series.

After that, all the elements were soldered into one circuit.

After assembling the device, the author tested its work on the phone. The solar battery was placed under light, and a mobile phone was connected to it via a USB connector.

As you can see in the photos, the phone battery started charging, which means that this device is working properly. This charger turned out to be very easy to assemble, contains a minimum of work with a soldering iron, but at the same time is very useful. Since its dimensions are minimal, it is quite convenient to take it with you and charge your phone if necessary.