Charging the battery with a weak solar panel with your own hands. The simplest solar charger. Step #1: Connecting to Battery

Solar energy is so far limited (at the household level) to the creation of photovoltaic panels of relatively low power. But regardless of the design of the photoelectric converter of solar light into current, this device is equipped with a module called a solar battery charge controller.

Indeed, the solar photosynthesis installation includes a rechargeable battery - a storage device for the energy received from the solar panel. It is this secondary energy source that is primarily served by the controller.

An electronic module called a solar controller is designed to perform a number of control functions during the charge/discharge process.

This is what one of the many existing models of charge controllers for a solar battery looks like. This module is one of the PWM type developments

When sunlight falls on the surface of a solar panel installed, for example, on the roof of a house, the device's photocells convert this light into electric current.

The resulting energy, in fact, could be supplied directly to the storage battery. However, the process of charging/discharging a battery has its own subtleties (certain levels of currents and voltages). If you neglect these subtleties, the battery will simply fail in a short period of operation.

To avoid such sad consequences, a module called a charge controller for a solar battery is designed.

In addition to monitoring the battery charge level, the module also monitors energy consumption. Depending on the degree of discharge, the solar battery charge controller circuit regulates and sets the current level required for the initial and subsequent charge.

Depending on the power of the solar battery charge controller, the designs of these devices can have very different configurations

In general, in simple terms, the module provides a carefree “life” for the battery, which periodically accumulates and releases energy to consumer devices.

Types used in practice

At the industrial level, two types of electronic devices have been launched and are being produced, the design of which is suitable for installation in a solar energy system:

1. PWM series devices.
2. MPPT series devices.

The first type of controller for a solar battery can be called “old man”. Such schemes were developed and put into operation at the dawn of the development of solar and wind energy.

The operating principle of the PWM controller circuit is based on pulse width modulation algorithms. The functionality of such devices is somewhat inferior to the more advanced devices of the MPPT series, but in general they also work quite effectively.

One of the popular solar station battery charge controller models in society, despite the fact that the device circuit is made using PWM technology, which is considered outdated

Designs using Maximum Power Point Tracking technology (tracking the maximum power limit) are distinguished by a modern approach to circuit solutions and provide greater functionality.

But if we compare both types of controller and, especially, with a bias towards the domestic sphere, MPPT devices do not look in the rosy light in which they are traditionally advertised.

MPPT type controller:

• has a higher cost;
• has a complex configuration algorithm;
• gives a gain in power only on panels of a large area.

This type of equipment is more suitable for global solar energy systems.

A controller designed for operation as part of a solar power installation. It is a representative of the class of MPPT devices - more advanced and efficient

For the needs of an ordinary user from a domestic environment, who, as a rule, has small-area panels, it is more profitable to buy and operate a PWM controller (PWM) with the same effect.

Block diagrams of controllers

Schematic diagrams of PWM and MPPT controllers to consider them with a layman's eye are too complex a point associated with a subtle understanding of electronics. Therefore, it is logical to consider only structural diagrams. This approach is understandable to a wide range of people.

Option #1 – PWM devices

The voltage from the solar panel travels through two conductors (positive and negative) to the stabilizing element and the separating resistive circuit. Due to this piece of the circuit, potential equalization of the input voltage is obtained and, to some extent, they organize protection of the controller input from exceeding the input voltage limit.

It should be emphasized here: each individual device model has a specific input voltage limit (indicated in the documentation).

This is approximately what the block diagram of devices made on the basis of PWM technologies looks like. For operation as part of small household stations, this circuit approach provides quite sufficient efficiency

Next, the voltage and current are limited to the required value by power transistors. These circuit components are in turn controlled by the controller chip through the driver chip. As a result, the output of a pair of power transistors sets the normal value of voltage and current for the battery.

The circuit also contains a temperature sensor and a driver that controls the power transistor, which regulates the load power (protection against deep discharge of the battery). The temperature sensor monitors the heating status of important elements of the PWM controller.

Usually the temperature level inside the case or on the heatsinks of power transistors. If the temperature goes beyond the limits set in the settings, the device turns off all active power lines.

Option #2 – MPPT devices

The complexity of the circuit in this case is due to its addition to a number of elements that build the necessary control algorithm more carefully, based on operating conditions.

Voltage and current levels are monitored and compared by comparator circuits, and based on the comparison results, the maximum output power is determined.

The main difference between this type of controller and PWM devices is that they are able to adjust the solar energy module to maximum power, regardless of weather conditions.

The circuitry of such devices implements several control methods:

• disturbances and observations;
• increasing conductivity;
• current sweep;
• constant voltage.

And in the final segment of the overall action, an algorithm for comparing all these methods is also used.

Controller connection methods

Considering the topic of connections, it should immediately be noted: for the installation of each individual device, a characteristic feature is working with a specific series of solar panels.

So, for example, if a controller is used that is designed for a maximum input voltage of 100 volts, a series of solar panels should output a voltage no greater than this value.

Any solar power installation operates according to the rule of balancing the output and input voltages of the first stage. The upper limit of the controller voltage must correspond to the upper limit of the panel voltage

Before connecting the device, you need to decide on the location of its physical installation. According to the rules, the installation location should be chosen in dry, well-ventilated areas. Avoid the presence of flammable materials near the device.

The presence of sources of vibration, heat and humidity in the immediate vicinity of the device is unacceptable. The installation site must be protected from precipitation and direct sunlight.

Connection technology for PWM models

Almost all manufacturers of PWM controllers require that the devices be connected in the exact sequence.

Peripheral devices must be connected in full accordance with the designations of the contact terminals:

1. Connect the battery wires to the battery terminals of the device in accordance with the indicated polarity.
2. Switch on the protective fuse directly at the point of contact of the positive wire.
3. Attach the conductors coming from the solar panel battery to the controller contacts intended for the solar panel. Observe polarity.
4. Connect a test lamp of the appropriate voltage (usually 12/24V) to the load terminals of the device.

The specified sequence must not be violated. For example, connecting solar panels first when the battery is not connected is strictly prohibited. By doing this, the user runs the risk of “burning” the device. The diagram for assembling solar panels with a battery is described in more detail.

Also, for PWM series controllers, it is not permissible to connect a voltage inverter to the controller load terminals. The inverter should be connected directly to the battery terminals.

Procedure for connecting MPPT devices

The general physical installation requirements for this type of device do not differ from previous systems. But the technological setup is often somewhat different, since MPPT controllers are often considered more powerful devices.

For controllers designed for high power levels, it is recommended to use large cross-section cables equipped with metal end caps for power circuit connections.

For example, for powerful systems, these requirements are supplemented by the fact that manufacturers recommend using a cable for power connection lines designed for a current density of at least 4 A/mm 2. That is, for example, for a controller with a current of 60 A, you need a cable to connect to the battery with a cross-section of at least 20 mm 2.

Connecting cables must be equipped with copper lugs, tightly crimped with a special tool. The negative terminals of the solar panel and battery must be equipped with adapters with fuses and switches.

This approach eliminates energy losses and ensures safe operation of the installation.

Block diagram of connecting a powerful MPPT controller: 1 – solar panel; 2 – MPPT controller; 3 – terminal block; 4.5 – fuses; 6 – controller power switch; 7.8 – earth bus

Before connecting to the device, you should make sure that the voltage at the terminals matches or is less than the voltage that can be supplied to the controller input.

Connecting peripherals to the MTTP device:

1. Switch the panel and battery switches to the “off” position.
2. Remove the protective fuses on the panel and battery.
3. Connect the battery terminals with a cable to the controller terminals for the battery.
4. Connect the terminals of the solar panel with a cable to the controller terminals marked with the corresponding sign.
5. Connect the ground terminal to the ground bus with a cable.
6. Install the temperature sensor on the controller according to the instructions.

After these steps, you need to reinsert the previously removed battery fuse and turn the switch to the “on” position. A battery detection signal will appear on the controller screen.

The device screen will show the voltage value of the solar panel. This moment indicates the successful launch of the solar energy installation into operation.

Conclusions and useful video on the topic

The industry produces devices that are multifaceted in terms of circuit designs. Therefore, it is impossible to give unambiguous recommendations regarding the connection of all installations without exception.

However, the main principle for any type of device remains the same: without connecting the battery to the controller buses, connection to photovoltaic panels is unacceptable. Similar requirements apply for inclusion in the scheme. It should be considered as a separate module connected to the battery via direct contact.

If you have the necessary experience or knowledge, please share it with our readers. Leave your comments in the block below. Here you can ask a question about the topic of the article.

Fans of outdoor activities often face the problem of discharged batteries of mobile phones, navigators, tablet PCs and other equipment necessary for a hike. Spare batteries are not the best solution. We suggest you try making a solar charger with your own hands. This way you can not only ensure uninterrupted communication while traveling, but also save a lot of money.

Determining charging parameters

To determine the power of a solar battery, you need to know its purpose. In order to charge a mobile phone and navigator, a voltage source of 6 V with a power of about 4 W is sufficient. A tablet PC, camera and laptop will require 12 V voltage with a power of 15 W. Making a solar battery yourself is a troublesome task; it’s easier to purchase a folding structure ready-made at a radio store.
It should be taken into account that the charging voltage (charger) must correspond to the parameters of the battery of the device being charged. The charging process will not occur if the charger voltage is lower than that of the battery. Exceeding this leads to destruction of the plates and failure of the battery.

DIY solar charging circuit

You can assemble a solar battery charger with your own hands using a simple scheme. Battery GB2 is connected to the same terminals GB1 of the solar battery. VD1 (Schottky diode), for example, MBR140 or 1N5817, 1N5818, is connected in series to the circuit so that the battery does not discharge through the solar panel. The principle of its operation is no different from other semiconductor devices using the pn junction principle, but is based on the use of a metal-semiconductor junction.

A diode of this type has an advantage over other diodes: the voltage drop when using it does not exceed 0.4 V. For a 6V battery, one diode is enough. The line on the diode body indicates the cathode, the other output is the anode. The circuit can be simplified if you purchase a battery with a built-in reverse diode.

What you need to make your own charger

So, to make a charger you will need: a solar flexible battery, a two-core copper cable with a core cross-section of 0.75 mm², a Schottky diode, two PLUG-type plugs (or similar) for connecting connectors XS1 and XS2, two JACK sockets, a plug such as Charger from 220 V mains and hot melt adhesive. Headphone jacks can be used to make connectors. If you need to charge AAA or AA batteries, you must purchase a special container. These parts are available on the radio market or in a special store. Plugs for charging modern mobile phones are unified for micro-USB. In the event that an old-style plug is required to charge a cellular terminal, you should purchase a universal adapter, which should not be included in the circuit on an ongoing basis: in the future, these will not be used anyway.

Build process

Assembling a solar battery charger with your own hands is quite simple. A two-core cable must be soldered to the outputs of the solar flexible panel, and a plug must be soldered to the other end. If the solar panel is already equipped with an output connector, you need to select a mating part for connecting it with the rest of the device.
The next stage is assembling a container for charging AAA (AA) batteries. It is advisable to use a case for three batteries: two places in it will serve their intended purpose, and in one place it is necessary to assemble a circuit with a Schottky diode. We insert a two-core wire, limited by a plug, into the housing, fix it with hot glue and connect it to the circuit. For reliability, the entire compartment with the circuit can be completely filled with hot glue.

If you only need to charge laptops, tablet PCs, cameras and mobile devices, the diode circuit can be assembled in the XS2 plug housing, where hot-melt adhesive should also be used for fixation. For ease of switching, it is advisable to make an adapter cable limited to the appropriate connectors. If you need to control the current during charging, you can sequentially connect an ammeter to the circuit, for which you can use the cheapest Chinese test

Solar technologies for converting light into electrical energy have become very popular today and their number is growing every day. I suggest you assemble a very simple solar battery charger with your own hands. You can use it for its intended purpose on any sunny day and charge your mobile phone or tablet computer from it. And to create this useful design, you only need the ability to use a soldering iron, some money to purchase the necessary components and time.

As mentioned a little above, it will take a little money and time. Everything you need can be purchased very cheaply in Chinese online stores with free delivery to Russia. So, we need:

Solar cell 6V, 50 mA or any other with better parameters. You can buy a universal case, or you can adapt something you already have on hand. Glue, soldering iron and mounting wires.

Open the cover from the universal housing. It already has four slots for screws. Place the cover on the table and carefully make a hole on the left or right for the mounting wires.

A larger hole must be carefully cut in the lower part of the case. The hole must be of a suitable size to secure the socket in it, but keep in mind that the socket must fit snugly in it. Therefore, first cut a small hole and gradually adjust it, trying on the socket. The main thing is not to rush and don’t worry.

Take the solar module and, without unnecessary fuss or haste, place the mounting wires from it inside the housing. This makes it possible to install the battery on top of the case. The next step is to take the car socket and, leading the wires inside through a special hole in the bottom of the case, push it tightly into place.

Using a special tool, I hope you know, connect the red and black wires from the module and the car outlet together.

Hide all the wires inside the case and close the cover, then screw it to the bottom of the universal case and glue the solar module to it. Now on any clear day you can charge your mobile phone without any problems

The circuit shown in the figure below is an excellent and simple automatic charger that can be used to charge 12 volt lead acid batteries from solar panels. You can take any ready-made solar panels, because they can be easily ordered from popular online auctions.

The basis of the microcircuit design is an integrated voltage stabilizer. The BC548 transistor works like, which will disconnect the microassembly from the solar battery when the battery is fully charged.

The circuit compares favorably with other similar ones in that it has a voltage that increases the low voltage level from solar cells in low light on a cloudy day to the 5V required by a mobile phone. Practical operation of this charger has shown that this design produces an output of up to 100mA.

PC1- three volt solar battery
Capacitors: C1 22 uF, 10 v; C2 100 pF; C3 10 uF, 16 v
Resistors: R1 1.5 kOhm; R2 3.9 kOhm; R3 10 kOhm; R4 180 Ohm; R5 4.7 kOhm; R6 10 Ohm L1 50 to 300 mH
D1 1N5818 Schottky diode
Transistors: Q1 2N4403; Q2 2N4401
J1 - output jack for your mobile phone

The choke is made from a piece of ferrite rod from the magnetic antenna of CD receivers. We select the number of turns experimentally based on the maximum output current - approximately 20-50.

Using this device, you can obtain a standard constant voltage of 5 V. The design is recharged from a standard solar battery, inside there are two AA batteries and a stabilizing inverter on the LT1302 chip.

The memory circuit is shown in the figure below:

A solar battery with a voltage of 4.5 Volts and a current of 900 mA is connected to contacts 1-1. When testing the circuit, you need to make sure that the device is capable of charging NiMN from solar energy.

The assembled circuit can be placed in a tin can. Four AA batteries (or 2 lithium) are placed in the free space.

Today, technologies that save energy and are environmentally friendly are in trend. Many people choose to use solar panels for a wide variety of purposes. There is always a use for such a device in home use. For example, for the same charging a mobile phone.

Anyone can make such a solar battery charger with their own hands, and our article will help you with this.

Application

Every year summer comes. And this is the time when everyone goes on vacation to the sea or nature. And here it would be completely useful to make sure that everything you need is in its place and works properly. And the most popular thing is a mobile phone. As you know, it needs to be charged, and in the forest or in nature this is not always convenient. An excellent solution would be to use a solar-powered charger, which you can easily do yourself.
This device will allow you to:

• don’t worry about charging your smartphone somewhere far from an outlet;
• Do not spend extra money on purchasing such chargers. Purchased models of such devices are quite expensive;
• not be dependent on electricity;
• be constantly in touch and use all the functions of your phone anywhere in your holiday;
• and another plus is the compact size of such a charger;

Note! You can make both a mini charger and a slightly larger device.

• do not carry a lot of unnecessary things with you to recharge electrical appliances.

This DIY mini solar battery has a lot of advantages that will be invaluable during any vacation.

Appearance

The design that a mini solar battery can have with your own hands can be different and, in principle, depends on you. The only thing you need to remember about is the features of use and functionality.

Charging design

It is assumed that such a device, designed to charge a cell phone, should be portable so that it can easily fit in a bag or even a pocket. Therefore, a charger of this type is often made foldable. Also, the body of a homemade product must withstand minor mechanical stress. Otherwise, it may simply fall apart in your pocket when moving.
At the same time, there are situations when a solar-powered smartphone charger is intended to be used at home (office, home, etc.) without transportation over significant distances. Then you don’t have to worry so much about the strength of the case.

Note! To add beauty to your homemade charger, you can use various decorative decorations. However, in any case, they should not affect the comfort of using a homemade device.

In order for a device to perform its intended function, a correct assembly diagram is needed. Depending on the type of charging, the circuit may differ slightly.

What we collect

Let's look at how to assemble a mini solar battery with your own hands using the example of a folding charger for a cell phone. This device will have the following characteristics:

Approximate view

• power - 20 watts;
• the design consists of 2 panels (12V - 10 watt). The size of the panels is 30x35 cm, and when unfolded, a homemade solar panel will be 35x60 cm;
• stabilized voltage for output - 14V-20 watts;
• The design has a built-in 14.8V battery – 4.3 ampere-hours. This battery is usually used to power a tablet or laptop;
• two USB outputs, each 5V – 4.3 ampere-hours. As a result, the total is approximately 5V - 8.6 ampere-hour.

As you can see from the photo, the design has the appearance of a diplomat. When closed, it completely prevents any kind of damage to the solar panel.
In essence, such a charger for a cell phone consists of two chargers with 7.4 V batteries built into them - 4.3 ampere hours.
To assemble such a device, you will need:

• two solar panels (in the example, 12V-10 watt panels are used). You can use a variety of models with aluminum frames. It all depends on your financial capabilities;

Note! You can use solar panels made in China. They will cost much less.

• loops. With their help, two panels of our “diplomat” will be connected to each other. They can be removed from the old cabinet. Usually one or two loops are needed;
• batteries;
• USB sockets. We take them from the old system unit. They can also be cut off from the USB extension cable;
• two ultra-bright LEDs. They will be needed to create a charging indication, as well as to illuminate the surrounding area (if there is such a need);
• switches and other small parts.

Some parts for assembly

Since the battery cannot be completely discharged, in our homemade device it is necessary to use a battery discharge control unit. It consists of a built-in battery. This battery is switched off in a situation
reducing the voltage on existing lithium batteries (up to 6.1V).
Note! This battery can be easily adjusted to the voltage you need.
The battery can also turn off if there is a short circuit at the output.

Assembly Description

Assembling a charger for any type of smartphone strictly according to the diagram. In our case, the following scheme will be used.

Assembly diagram

Here is a complete assembly diagram for one future charging unit. In this situation, it is possible to parallelize the panels to use them as one block.
Note! There are dotted lines on the diagram along which the second panel should be connected to a single stabilization unit.
The circuit is assembled on a body, which can be wooden boards, knocked together like a chessboard or other structures of a similar structure.

Explanation of symbols

As you can see, there are special marks on the diagram, which are symbols of parts. Therefore, in order to correctly connect the components together, you need to know the decoding of these symbols:

• SZ1 – solar panel;
• VD1 and VD2 are diodes. These elements will protect the panel from polarity reversal, which is formed at the input when charging from the network adapter;
• DD1,DD2 - stabilizers. They allow you to achieve a stable voltage when charging;
• R1, R2 are resistors. With their help, the required voltage is set to recharge the batteries;
• R4 is a resistor required to limit the current in the presence of a discharged battery;
• R5 is a resistor. It sets the current flowing through the backlight and display LED;
• R6-R9 - resistors on which dividers are assembled, creating the necessary levels for USB;
• SA1 is a key switch. With its help you can select the mode of use. If the mode is 14V, you can charge the batteries (external lead, etc.), and in the 8.4V mode, you can connect the built-in battery to the circuit. The built-in battery will be supplied with voltage from the solar panel.

Knowing this decoding, you can easily assemble a portable solar charger.

How to use the device

Now that we know how the circuit is assembled, we need to figure out how it will work. If the battery is completely discharged, the device can only be turned on in SA1 8.4V mode. Here, contact group SA1/2 unlocks the battery, and it is connected for charging automatically.

Ready to charge

When the battery is charged, the device will turn on in SA1 8.4V mode if you quickly press the KH1 button. When charging the mobile phone is complete, move SA1 to the 14V position. This will turn off the built-in battery, which will be indicated by the LED turning off.

Conclusion

If you strictly follow the diagram and correctly connect all its components, you will get a compact portable device for charging your mobile device from solar panels. This homemade charger will allow you to relax comfortably in nature and always stay in touch with civilization.

Details about the motion sensor switch
Selecting a street motion sensor to turn on the lights

For a long time, solar panels were either bulky panels for satellites and space stations, or low-power solar cells for pocket calculators. This was due to the primitiveness of the first monocrystalline silicon solar cells: they not only had low efficiency (no more than 25% in theory, in practice - about 7%), but also noticeably lost efficiency when the angle of incidence of light deviated from 90˚. Considering that in Europe in cloudy weather the specific power of solar radiation can fall below 100 W/m 2, too large areas of solar panels were required to obtain any significant power. Therefore, the first solar power plants were built only in conditions of maximum light output and clear weather, that is, in deserts near the equator.

A significant breakthrough in the creation of photocells has returned interest in solar energy: for example, the cheapest and most accessible polycrystalline silicon cells, although they have lower efficiency than monocrystalline ones, are also less sensitive to operating conditions. A solar panel based on polycrystalline wafers will produce enough stable voltage under partly cloudy conditions. More modern solar cells based on gallium arsenide have an efficiency of up to 40%, but are too expensive to make a solar cell yourself.

The video talks about the idea of ​​​​building a solar battery and its implementation

Is it worth doing?