Solar charger: device and principle of operation of charging from the sun

Amir Gumarov
Checked by a specialist: Amir Gumarov
Author: Yana Mokeeva
Last update: November 2019

More and more lovers of outdoor activities prefer to spend their vacations and weekends closer to the pristine nature. But it’s difficult for a modern person to refuse the benefits of civilization - which of us does not take a mobile phone, laptop or camera on a trip?

But if there is a solar charger in your luggage, the problem with the power of the devices will be solved. It remains only to figure out how to choose the right device. The article we have presented will be of great help in clarifying all issues.

What is solar charging?

These chargers are capable of converting solar energy into direct current. They can work with various models of navigators, players, laptops, telephones, cameras and other portable devices.

But the charging time directly depends on the power of the device itself and the type of discharged device, therefore, in order to choose a truly practical and versatile device, it is worthwhile to understand its characteristics.

Instrument Design Features

The device itself consists of a crystal panel, a charge / discharge level controller and a converter of solar energy into electrical energy.

Some models are also equipped with a buffer battery of several lithium cells, which allows the device not only to convert, but also to accumulate energy to give a charge even in the dark.

Solar charge application
Just a couple of years ago, solar chargers were quite expensive devices, and today it is a mass product with an affordable price.

Benefits of Solar Charges:

  • Universal - adapted for various devices (USB connectors are provided on the case, and most models are additionally equipped with special adapters for various types of electrical equipment).
  • They take up little space in travel luggage.
  • There is a wide selection of shapes, colors, sizes and power for various needs and aesthetic taste.

Well, the most significant drawback for all solar exercises is the long time that they need to accumulate “power”. In addition, it should be understood that if almost any model can cope with the power supply of a mobile phone or camera, then an active “absorber” of energy such as a laptop will already require impressive power from a solar battery and a capacitive battery.

The principle of operation of the device

Solar-powered portable chargers are stand-alone systems that can process energy from both the rays and the mains, fluorescent lamps or a computer. Moreover, many models do not need the presence of intense sun - they accumulate a charge even on cloudy days, although the efficiency, of course, decreases (from 20 to 70%).

Charger Options
If you buy a device with the ability to connect to the mains, you can significantly save time on the accumulation of charge in cloudy weather

The device works like this: crystals on the panel absorb solar energy, its converter “processes” it into electric current, which enters the power source. When a mobile phone or other device is connected to this source using a cord, the accumulated energy gradually flows into the discharged device.

Types of Solar Charges

As for the appearance - here the manufacturers have tried not only to diversify the color gamut and the shape of the devices, but also to make the device as convenient as possible for use in various situations. Consider the most popular options.

Monoblock - a compact device made of a panel and a drive enclosed in a solid case made of metal or plastic. Such a device will “save” a discharged phone on the beach or on a picnic and will not take up much space in an ordinary bag.

Monoblock charging
Monoblocks are convenient for everyday life - they do not take up much space and can be charged not only from the sun, but also while working on a laptop or computer

Flexible panel - Thin folding or expandable panel with photocells. It takes up little space in luggage, and weighs much less than its solid competitor, enclosed in a case. But, despite the decent area of ​​"coverage", flexible plates they accumulate solar charge almost two times slower than monoblocks.

In addition, most panels work only from direct sunlight, without storing energy for future use - they do not have a built-in battery. However, you can always understaff your charging with an external drive of the required power.

So flexible panels are a good option for solving the problem of recharging low-power devices with “stationary” rest - in the country, fishing, with a tent. But for a hiking trip it is better to look at another option.

Flexible solar panel
During movement, the flexible panel can be folded compactly and placed in the trunk or attached to the roof of the car, and on a halt - just spread out in the sun

Built-in charge - the device consists of solar panelsthat are attached to the outside of bags or backpacks.They allow you to recharge devices directly during the journey or to accumulate a charge in the built-in battery.

And such an accessory can be used for its intended purpose - to carry any items or the same electronics, which is very convenient for those who are interested in hiking or working in the open air.

Solar powered backpack
Although the “energy backpacks” look attractive and stylish, you can also temporarily attach any other type of charge to your bag (many models are even equipped with special carabiners) and not worry about the safety of the device during rain or cleaning

Cots - it can be several flexible panels compactly folded in a “stack”, or a variation of two monoblocks enclosed in a rigid case in the form of a drop-down book.

The main goal of such a device is to minimize the "capture" of usable space in the volume of your luggage and increase efficiency due to a larger number of photocells. A nice bonus - most models are equipped with mounts on a backpack or car glass.

Folding memory with adapters
The size of the “clamshell” can be selected based on your needs: to charge a mobile device, the size of the phone itself is enough, but for laptops and tablets the panel, even when folded, will be no less than sheet A5

But regardless of the design, all solar charges work on the same principle, so consider the important technical nuances that will help when buying a device.

How to choose a suitable option?

To begin with, it is worth deciding on the number and types of devices that you plan to charge from solar charging. The power of the device and the type of output port depend on these parameters.

Device for charging multiple devices
If your device has several USB ports, you can connect and charge various devices at the same time, most importantly, to allow battery power

The characteristics of various devices can be clarified by looking at the instructions for their use, and in some devices the operating voltage is indicated on the charger, which is included in the kit, so it will be easy to navigate. In extreme cases, the desired adapter can always be purchased.

Key options and nice additions

From the characteristics of the charging current depends on the time that the device will need to power up various devices. This indicator is measured in amperes and is indicated on the device ports.


  • 1 ampere - designed for mobile phones, electronic cigarettes, watches, players.
  • 2 amperes - suitable for tablets, smartphones, digital cameras and video cameras.
  • 2.5-3 amperes - will cope with charging netbooks and laptops.

It is also important to know the output voltage, because rechargeable devices can exceed the capacity of solar charging in power. So, for most phones and simple tablets, a 5-volt output will be required, for digital cameras and gaming gadgets - 9, and for laptops and car refrigerators - 12-24.

But still, the main characteristic of the charger is the power of the solar panel. The battery charging time directly depends on this indicator. And here it all comes down to the characteristics of light-absorbing panels.

For example, elements with a power of 5 W (standard budget option) will have a current of 900 ma hours, and for 10 W - 1500 ma. That is, to charge the phone from solar charging at 5 W, it will take 2-3 hours, but a panel with a power of 10 W will do just one and a half.

Foldable laptop charger
For powerful devices such as gaming tablets and laptops, it’s better to buy folding models from several panels that quickly generate a charge

In addition, devices with panels whose power does not exceed 2 W are used only to accumulate the charge of the built-in battery. And in order to directly charge devices from sunlight, you need panels with a power of 3 W or more.

Other important parameters:

  1. Battery availability - if the device does not have a drive, it can only work while it is in a lit place.Devices with batteries are capable of delivering a charge at any time of the day, as well as charging from other sources - a laptop’s USB port or an outlet with a 220V connection.
  2. Type of photocells - it is believed that single crystals (their efficiency at the level of 13-18%) absorb sunlight more efficiently. In polycrystals, this figure is lower - about 10-12%. You can distinguish them even with the naked eye - polycrystalline panels have a dark blue hue, and their competitors have black.
  3. Interface - Universal solar charging is equipped with informative USB, where you can choose the option you need, depending on the type of discharged device. Some devices are also equipped with an indicator of the intensity of sunlight, which will help determine the optimal location for a quick charge.
  4. Protection - a priori, all devices have a security system that allows their operation in nature. But for fans of extreme adventures it is worth looking for a device with enhanced protection from rain, dust, dirt, shock and other force majeure.

Additional features are most often represented by the "flashlight" or "lamp" function. This may be relevant not only for outdoor enthusiasts, but also for motorists - when replacing a wheel or repairing on a night road, a bright light will become an indispensable assistant.

Of the other bonuses, manufacturers can offer a USB hub or Wi-Fi hotspot. But, of course, any additions significantly increase the final cost of the product. And whether you need them is up to you.

In terms of shopping intensity, the following models lead us:

General recommendations for operating the memory

Devices with a built-in battery must be fully charged before the first operation, and not from the sun, but from the mains. Then connect any device to the charger so that it receives energy and discharges the drive.

After that, the panel can be substituted under the rays and compensate for the lost charge. For models working directly from the sun, this rule does not work - they can be immediately installed on illuminated areas and connected devices.

Solar charge example
Most solar chargers are designed to operate in temperatures ranging from -20 to + 45 degrees, but there are also special models that work in extreme climates, only they are made to order

To maximize the efficiency of solar charging, we recommend the following:

  1. Position the device so that the rays fall on the panel at a right angle. Even if the sun is not at its zenith, you can give the charging the correct position by lifting it at an angle of 40 degrees using some kind of backup. So you can collect a charge of 20-30% more than if you lay the panel horizontally in a bright place.
  2. Use the device with the drive, and not only at halts, but also when traveling by car or on a camping trip. Such a tandem will be able to collect energy for 2-3 phone charges even in cloudy weather without direct sunlight.
  3. Keep in mind that in most folding devices, the panels are connected in series, so it is important that all elements are evenly lit.For example, even if the shadow covers only half of the first of the four panels, the battery power will drop by half.
  4. In order for high-capacity batteries to reach the declared parameters, they are recommended to be “dispersed” - completely discharged, then charged to 100%. And so 3-4 times.
  5. For a long break (a month or more), store the memory at room temperature. If this is a device with a built-in battery, it must first be charged up to 50-70%.

And the last piece of advice - even if the charging has become worse or completely out of order, do not disassemble it yourself, so as not to damage the elements of the system and the case itself. The disassembled device is automatically withdrawn from the warranty, so it is better to contact an authorized service center or the supplier.

How to make a charger yourself?

Although modern chargers have already ceased to be premium-class devices and are quite affordable for the average consumer, if you want to save money, there is always the opportunity to make such a device yourself.

DIY charging
An example of a home-made device in a rigid case made of a metal can equipped with a USB connector and an energy converter for charging low-power devices

 To make a simple solar charger, you need to purchase several basic elements:

  • poly or single crystal panel;
  • holder for batteries;
  • Schottky blocking diode;
  • socket for connector;
  • charge controller (however, if charging will produce 0.5-5V, you can use a cheaper 5V boost converter instead of the controller).

As for the panel itself, here you need to make a small calculation of the number of elements, based on the power of the device that you plan to charge.

For example, if the charge current for a battery is about 10% of its capacity, then a current of 2A is needed to charge 20,000 mA, and it will take about 14 hours to power the device. If you double the current to 4A, the time for recharging will be reduced to 7 hours.

DIY storage
Replacing the controller with a converter will allow you to collect the memory even with a low-power battery from a solar lawn lamp - anyway, we get the required 5V at the output (though it will take a long time to charge)

Depending on the current parameters for future charging (2 or 4A), crystalline elements are also selected. Usually, 1 part produces about 0.5V, that is, to get at least 5V you will need 10-12 elements.

Then they need to be sequentially soldered together. If the panel from the flashlight is used, then even the standard 70 * 70 cm can output from 2.5 to 4.5V, so it is better to check with a voltmeter.

The final stage is to enclose a home-made charge in any suitable frame (even a candy can is suitable) and equip with a USB connector. Then you need to solder the blocking diode to the connector, as well as the wires from the solar panel to the converter and holder according to the diagram below.

Assembly diagram
The Schottky diode is necessary so that when the device is turned on, the batteries should not be discharged through the solar battery. You can purchase it, like other components, on radio markets or on the Internet

It remains to check the operation of the device in the sun with any discharged device. If everything is in order, you can use the appropriate adapters and charge various devices.

Photo instruction for independent masters

You can easily assemble a compact charger with a USB port to power your phone with your own hands. All components are available for sale, in extreme cases they can be written out. Homemade will cost tens of times cheaper than a factory-made product, especially if it is widely advertised.

When purchasing accessories for assembling the device, you need to consider that you need to buy a solar battery with a voltage of 5V or more. We already spoke about the battery voltage, it is 3.7 V. However, we did not mention an important subtlety - “PCB protection” should be indicated in the labeling or technical documents of the battery. This means that it is protected from deep discharge and overcharge.

Two more connectors for 2.5 mm are required: one with a latch on the panel, the second with a wire. You will also need a boost circuit on USB to supply DC power.

Stocked up with everything you need? Let's proceed to the assembly:

In addition, you need to solder the diode.It is connected on one side by a wire to the battery, on the other - with the middle leg of the connector. It is desirable to make soldered joints as close as possible to the diode, all nodes must be protected by heat shrink tubes or at least glue drops.

With the rules for the selection of solar panels for arranging a private house or cottage next articlededicated to this interesting question.

Conclusions and useful video on the topic

To get a visual idea of ​​solar chargers and the principles of their work, we offer to see our selection of videos:

Practical tips and tricks for choosing charging for different devices. You can look inside and study the monoblock scheme with the author of this video:

How to assemble a do-it-yourself-powered battery charger:

Thanks to the technological progress and the bright minds of the inventors who made available the energy of the sun for ordinary users. Thanks to such chargers, you can not worry about the fact that on vacation at the right time you will be left without communication with civilization.

Well, if there are difficulties with the selection of the device, you can always seek the advice of professionals who are versed in electrics.

Tell us about how you used solar charging in camping conditions, on a picnic or on the road. Please write comments in the block below. Ask questions, share impressions and useful information on the topic, publish photos.

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Visitors Comments
  1. Artyom

    In the summer I often go hiking for a week or two.I bought charging in the spring in the form of a candy bar to recharge the camera and phone. At the crossings, I fastened it at the top of the backpack, gaining, albeit more slowly than at the halt, but all the time. I still take a spare powerbank in case of rain, but the overall weight of the stacking has decreased, plus I can now use the phone more, for example, I read it in the evening.

  2. Evgeny Slavin

    I read the article, and I still have a question: why didn’t modern power banks please? They take up less space, and their energy output is quite fast and does not require special conditions (for example, direct sunlight). In addition, they are widespread, you can find them in any electronics store, but I rarely see solar-powered memory, only in specialized centers.
    It is clear that this is beneficial for the environment and does not require recharge from the outlet.
    But to wait for sunny weather, especially in the latitudes of the North-West (St. Petersburg, Murmansk), and even in autumn and winter ... Well, this is not an option.
    But for a trip abroad, and even for a camping trip, I would have bought such an eco-charge!)

    • Michael

      I can answer what did not please: a small supply of charge. Powerbank, even with a large volume, on all devices, if you are away from civilization for a couple of weeks, and not enough for a smartphone. A device that can draw energy from the sun is more productive.

    • Eugene

      If only because when the backpack is 30 kg behind the back, it’s somehow no longer a week (to me up and even the other side) by itself - dragging along a dozen “power-cans” ...

  3. Semen

    Well I do not know. Of course, solar panels are the future, here I have no doubts. But at the moment they are still too expensive with dubious effectiveness. So far, this is not a “mass product with an affordable price”. A charger, at the price of half, or even 2/3 of a smartphone, is expensive.

    • Expert
      Amir Gumarov

      Semyon, the issue of mass is not only solved at the cost, but also the need for such devices. Indeed, in order to recharge the phone once, a power bank is enough - it is easier. and cheaper. But if you, for example, go to the rafting, or to the mountains for a week, then you won’t get enough power banks here, and solar panels just solve the problem. But you are right, people are not sent to such extreme adventures en masse.