DIY solar street lamp. Making a solar garden lamp with your own hands

Many summer residents have solar-powered garden lights on their property, mostly made in China, which are not particularly reliable.

Simple modifications can significantly improve the performance characteristics of such lamps.

Garden lamps not only decorate the area, but also illuminate paths, making evening walks in the garden safe. All garden lamps are divided into stationary and autonomous. Placing stationary lamps in a garden plot involves a significant amount of work on laying electrical cables and installing the lamps themselves. And their price is very high.

Stationary lamps on the site can be supplemented or even replaced with autonomous devices. They will be appropriate in literally every corner of the garden. Especially

Such lamps look impressive if you place them around the perimeter of the pond and along garden paths. There are also autonomous garden spotlights that are used to illuminate buildings and large ornamental plants.

Despite the variety of models of autonomous garden lamps, they are all assembled according to a standard design, which includes a solar battery, a battery, a voltage converter and an LED or LED module. Any of these components can be improved, thereby improving the performance characteristics of garden lamps - for example, the brightness or duration of their operation.

Do-it-yourself modification of the tower lamp

For example, the Tower lamp (Fig. 1) is assembled on a DA1-ANA618 pulse converter (or its analogues - ANA608, Y801, Y8018). The switching converter increases the voltage of the nickel-cadmium battery to the level required to turn on the HL1 LED. In addition, the converter monitors the voltage on the solar battery, and at dusk (when the voltage on the solar battery decreases) it turns on the lamp. The amount of current flowing through the LED, and, accordingly, the brightness of the LED depends on the inductance of inductor L1. In luminaires from different manufacturers, a choke with an inductance of 68-82 μH is installed. With this inductance value, the current through the LED does not exceed 12 mA, although the operating current for most low-power LEDs is 20-30 mA.

To increase the current value (brightness of the lamp), you should replace the standard choke L1 with a choke with an inductance of 33 μH. The current flowing through the inductor is very small. Therefore, you can use a choke of almost any design with a given inductance value (photo 1).

You should remove the old inductor from the board and onto it. place to install a new one. If the board is welded to the lamp body and the components are deployed inside the lamp, it does not have to be dismantled. It is necessary, using a desoldering pump, to remove the solder, and then remove the inductor from the board (photo 2).

Depending on the design, LEDs provide different brightness for a given operating current. For ultra-bright low-power LEDs, the brightness varies widely from 2 to 20 cd/m2 and higher. The garden lamp in question uses a flat-head LED, which, with an operating current of 20 mA, creates a luminous flux with a brightness of about 4 cd/mg. This is enough to illuminate an area within a radius of up to 1.5 meters. Simply replacing this LED with an ultra-bright 20 cd/m2 5013UWC LED will significantly improve the performance of your garden light.

As the operating current and brightness of the LED flashlight increase, the current consumed from the battery increases. Instead of a standard battery with a capacity of 600 mAh, it is necessary to install a nickel-metal hydride battery with a capacity of 1000 mAh of similar size, thereby significantly increasing the battery life of the lamp even in cloudy weather (photo 3).

It should be noted that nickel-metal hydride batteries of AAA size are currently produced with various capacities: 1,000, 1,100, 1,350, 1,800 and even 2,000 mAh. The larger the capacity of the installed battery, the longer the lamp will operate on a single charge.

Before purchasing a battery, be sure to check the voltage with a multimeter. For a nickel-metal hydride battery, the voltage at the electrodes does not exceed 1.3 V. For salt or alkaline batteries, the voltage at the electrodes is 1.50-1.57 V. Sometimes unscrupulous sellers, under the guise of high-capacity nickel-metal hydride batteries, sell salt batteries stylized as batteries .

Luminaires with three LEDs

To ensure that the lamp creates uniform illumination, instead of one LED, you can install three at an angle of 120 degrees. The LEDs are switched on in parallel to each other. Before installation, you should check the spread of their operating voltage, which should be minimal, otherwise only one of the three LEDs will light up brightly, and the rest will only glow dimly. A simple check is easy to carry out by assembling a test circuit (Fig. 2). If LEDs from the same batch are used, they will glow with almost the same brightness (photo 4).

It should be taken into account that the forward voltage drop for LEDs of different glow colors is significantly different (see table).

Therefore, when LEDs of different colors are connected in parallel, the one with the lower voltage drop will light up.

The LEDs are located on a board with a diameter of 15 mm. A drawing of a printed circuit board, an assembled LED module, and a solar-powered garden lamp with this LED module are shown in Photos 5-6.

You can make garden lamps that will burn in different colors - red, blue, yellow, green, white, purple. You just need to select the appropriate LEDs. Preference should be given to ultra-bright LEDs, which, at the same operating current, have significantly higher brightness than conventional ones (photo 7).

Dynamic multicolor light

Regardless of what color LEDs are chosen for a garden lamp, this color will be static, unchanged over time. A much more interesting effect can be achieved by using a three-color LED with a built-in generator. These LEDs are used in more expensive UFO lights and ball-shaped pond lights. Compared to conventional garden lights, the cost of dynamic lights is 15-20 times higher!

Three-color LEDs with a built-in generator contain a microcircuit on one of the electrodes that controls the operation of an RGB matrix mounted on the other electrode (photo 8). An LED has two terminals - a cathode and an anode. The anode lead is usually longer. A three-color dynamic LED is connected to the power source via a current-limiting resistor. The operating current of this LED is 20 mA. Dynamic LEDs must not be connected to a power source without a current-limiting resistor or applied with reverse polarity voltage. Maximum reverse voltage of more than 0.5-0.75 V destroys dynamic LEDs.

Three-color dynamic LEDs come with fast color changes (fast fading) and smooth attenuation (slow fading). The latter are most interesting for use in garden lamps. The color of their glow seems to flow from red to yellow, then to green, blue, white, orange and back.

Depending on the number of LEDs purchased and the place of purchase, the cost of LEDs varies significantly. Thus, a batch of 100 LEDs purchased on the radio market cost the author 10 rubles. per piece, and through the retail network these same LEDs are sold for 55 rubles.

It is impossible to connect a three-color LED with a built-in generator to a garden lamp instead of an installed white LED: it simply won’t work. work. And the reason is simple - a converter installed in a garden lantern produces a rectangular pulse voltage with a frequency of 200-250 kHz (photo 9). Each new pulse restarts the generator, built into a three-color dynamic LED, and for normal operation of the generator, the pulse voltage must be converted to constant voltage.

The easiest way for these purposes is to use a rectifying diode and a storage capacitor. The diode cuts off negative voltage surges from the converter, and the capacitor discharges in pauses between pulses to the LED. Thus, from an alternating voltage we obtain a constant voltage.

When choosing a diode and capacitor, preference should be given to surface mount components. It is highly desirable to install a Schottky diode, which has a minimum voltage drop of 0.12-0.14 V, and an operating frequency that reaches hundreds of kilohertz due to the short charge dissolution time. It is preferable to use a tantalum capacitor with low equivalent resistance (photo 10). Under these conditions, maximum rectifier efficiency is ensured.

The diagram of the lamp module is shown in Fig. 4, printed circuit board for the module and three-color LED - in Fig. 5, and the assembled module is in photo 11.

Since it is difficult to convey dynamic events within the framework of a magazine article, to illustrate the operation of a garden lantern with a three-color LED, a series of photographs is shown in photo 12.

Upgrading a garden light turned out to be a very simple task. You can decorate your garden with fantastic illumination based on mass-produced inexpensive garden lamps, modified with your own hands.

Do-it-yourself repair and improvement of solar lamps - photo

Rice. 1. Concept of the “Tower” lamp. Photo 1. Miniature inductors for wall mounting. Photo 2. Removing the inductor without dismantling the board. Photo 3. AAA batteries. Rice. 2. Schematic diagram of checking the brightness of the glow. Photo 4. LEDs from one batch have almost the same brightness. Photo 5. LED module assembly. Rice. 3. Printed circuit board for three LEDs. Photo 6. Lamp with three LEDs. Photo 7. Example of super-bright LEDs. Photo 8. Three-color LED with an RGB control matrix.

Repair and improvement of a solar-powered lamp - photo 2

Photo 9. Oscillogram of the pulse voltage generated by the converter. Photo 10. Tantalum capacitor. Rice. 4. Schematic diagram of a dynamic lamp module. Rice. 5. Printed circuit board of the dynamic lamp module. Photo 11. Assembly of the dynamic lamp module. Photo 12. Various phases of operation of a dynamic lamp with a three-color LED.

Many people are already familiar with garden lanterns that are charged from solar cells. These garden lanterns literally flooded the market, and due to their cheapness and novelty, many purchased dozens of them. But these flashlights do not last as long as we would like (no more than 5 years), at first the batteries die, and the transparent bulb loses its transparency due to ultraviolet radiation. As a result, there is no point in restoring these flashlights, since the batteries are not cheap, and the appearance is no longer the same.

But on the other hand, these garden lanterns have working solar cells that last quite a long time (about 25 years). From these solar cells we can make a low-power solar battery with our own hands, which is quite suitable as marching option for powering a radio or portable TV, not to mention charging a mobile phone.

The advantage of solar cells from garden lanterns is that they are coated with a transparent layer of polyester resin (the total thickness of the solar cell is 2mm), thereby adding strength solar cells and protecting them from atmospheric influences. As a result, they are difficult to break (while conventional poly and monocrystalline solar cells are 0.2 mm thick and as fragile as glass), and even those who hold a soldering iron for the first time can handle their soldering, because everything is connected with ordinary wires.

If you don’t have that many garden lanterns, you can purchase similar solar cells, but I want to note that the price of such elements (4.5V, 0.25W) will be $1.5-2 per piece, when ordinary polycrystalline cells have the same power , will cost $0.4 per piece.

How many elements will we need? Since the voltage of one element is 4.5V, to obtain 18V (to charge a 12V battery) we only need to connect 4 elements in a serial line. And then to increase the power of the solar battery, we connect the lines of 4 elements in parallel.

How much to connect in parallel depends on the number of elements available to you. In this case, there were 40 solar cells available, based on this, and a housing for them was built.

Since the solar battery was intended for use in camping conditions and could easily fit in the trunk of a car, it was decided to make it folding in the form of a book. The body was made of 50x32cm plywood with a thickness of 6mm and 2x2cm blocks.

The solar cells were glued to the base of the case with silicone.

After soldering the elements, do not forget to install Schottky diode so that in the absence of sunlight, the battery does not discharge through the solar cells.

To protect from rain and dust, we glue a piece of plexiglass to the frame. To prevent the plexiglass from being scratched when closing, pieces of felt were glued to the corners.

Hiking option homemade solar battery ready to use. Its total power is approximately 15W.

To power the equipment, batteries and an inverter (converter from 12V to AC 220V), for a camping solar battery, can be placed in any plastic container, or, for example, in a plastic tool box.

Many summer residents dream of decorating their garden plot at night with portable solar-powered flashlights, but many simply cannot afford such luxury. There is a way out: by assembling lamps with your own hands from inexpensive radio components, you can easily organize a real scattering of lights in the garden.

Purchased lamps more often disappoint than delight. They shine dimly, work only for a few hours and hardly last longer than two years. When assembling a garden lamp with your own hands, you determine the necessary parameters yourself and can count on a guaranteed result.

The operating principle of such a lamp is very simple. During the daytime, the sun hits a photocell, which generates electricity and charges a small battery. When the solar panel voltage drops, a transistor switch cuts off the current from the solar panel to the battery and supplies power to one or more bright LEDs. When voltage appears at the photocell contacts, reverse switching occurs.

What parts are best to order and where?

The most difficult thing is to get hold of solar cells. Substandard items are suitable; the easiest way to buy them is on various online auctions, such as Aliexpress. Select a module with an output voltage of at least 5 volts; the power must correspond to the number of LEDs. It is very important that the module has conductor taps; otherwise, buy those that come complete with flat conductors and a flux pencil.

The most expensive element of the lamp is the nickel-metal hydride or lithium-ion battery. You need batteries with a voltage of 3.6 V, they look like three AA batteries covered in film. The capacity must also correspond to the total power of the LEDs multiplied by the number of hours of battery life + 30%. Can be purchased together with modules.

Light sources are LEDs. Based only on the characteristics, you most likely will not be able to choose the appropriate level of illumination, so you will have to choose experimentally. It is recommended to use bright white LEDs BL-L513. They are easy to find in electronic components stores, for example, at Chip and Dip they cost 10 rubles. Each LED requires a 33 ohm current limiting resistor.

Also, for each lamp you need a 2N4403 transistor, a 1N5391 or KD103A rectifier diode, as well as a resistor, the value of which is calculated using the formula R = U baht x 100/N x 0.02, Where N- the number of LEDs in the circuit, and U baht— battery operating voltage.

How much will the parts cost?

In cheap Chinese lamps costing about 500 rubles. Only one LED is used, which is clearly not enough. Moreover, the battery voltage is 1.5V, which is why the light is very dim.

Elements	Price	Qty	total cost
Solar modules Eco-Source 52x19 mm	675 rub. for 40 pcs. (for 4 lamps)	1 set	RUB 675.00
Battery SONY HR03 (1.2 V 4300 mAh)	885 rub. for 12 pcs. (for 4 lamps)	1 set	RUR 885.00
LEDs BL-L513UWC	10 rub./pcs.	12 pcs.	RUR 120.00
Resistor CF-100 (1 W 33 Ohm)	1.8 rub./pcs.	12 pcs.	RUR 21.60
Transistor 2N4403	6 RUR/pcs.	4 things.	24.00 rub.
Diode 1N5391	2.5 RUR/pcs.	4 things.	RUB 10.00
Resistor CF-100 (1 W 3.6 kOhm)	1.9 RUR/pcs.	4 things.	7.60 rub.
Total:			RUB 1,743.20

It turns out that to assemble one high-quality lamp you need approximately 435 rubles worth of components. But from these same parts, by purchasing the last 3 items, you can make 12 analogues of cheap Chinese lamps.

Soldering a simple circuit and assembling the parts

To assemble such a circuit, it is not necessary to have a textolite base and etch out the tracks. The cathodes (short leg) of all LEDs are assembled into one unit, and 33 Ohm resistors are soldered to the anodes (long leg). The tails of the resistors are also soldered together and soldered to the collector of the transistor. A 3.6 kOhm resistor is connected to the base of the transistor, and the cathode of the rectifier diode is connected to the emitter. The anode of the diode is connected to the base resistor, and the positive pole of the solar modules is supplied to the same unit. The negative from the modules and the battery is connected by wires to the combined cathodes of the LEDs. The positive terminal of the battery is connected to the emitter of the transistor.

Electrical diagram of the lamp

Individual solar modules have a voltage of 0.5 V, and to charge batteries you need 4.5-5 V. Therefore, individual modules must be combined into chains. First, solder the conductors to the modules if there are none. To do this, cut the flat conductor into strips slightly longer than the width of the module. If the module is 19 mm, cut 25 mm.

The positive contact of the module is located on the back side, and the negative contact is that same central strip on the front part. You need to run flux along this strip - this is a colorless marker from the kit. Then a piece of conductor is laid over the contact. All that remains is to slowly move the soldering iron from above: a thin layer of tin is already on the conductor. The remaining tail is soldered to the contact on the back of the next module and so on along the chain until 10 modules are assembled in two rows.

Between the rows you need to make a jumper from a flat conductor, and solder thin copper wires to the remaining two ends. Be careful when handling the modules, they are very fragile. It is also not advisable to overheat them, so do not keep the soldering iron in one place for too long.

Design and assembly of the lamp

The lamp requires a housing, preferably waterproof. It is very convenient to use an empty canning jar with a screw-on lid.

Example of parts layout

To assemble such a lamp, you need a piece of plywood to glue two rows of modules onto it. The proposed photocells have a size of 52x19 mm; folding them in two rows, you get a rectangle with dimensions of approximately 110x110. You can glue the modules using double-sided tape for mirrors, but do not press down too hard.

Before gluing the modules, cut a hole in the center of the board for the lid of the jar and secure it inside with a couple of drops of hot glue. You need to pierce two holes in the cover to enter wiring from the modules; do not forget to restore the seal later.

To conveniently place electronics inside, glue a small foam washer to the inside of the lid. If you don’t bite the legs when soldering the circuit, you can stick the elements into the foam and fix them that way. And if you make rectangular cuts in the foam, you can easily insert batteries into them. For contact, use a pair of flattened balls of aluminum foil with wires soldered to them.

Before closing the lid, warm the inside of the jar well with a hairdryer. This way the parts will oxidize less, and condensation will not appear on the walls of the jar.

Some operating secrets

Lamps do not tolerate cold very well, so it is advisable to bring them into a warm room for the winter. The batteries need to be completely discharged by covering the solar panel with something opaque. Wrap the batteries separately in paper to help them last longer. Also consider covering the modules with a clear protective coating or using film solar cells. In general, such lamps last for 6-7 years of active use.

The previous article already talked about how to make a solar panel from old garden lamps. Since the power of the solar cells used in them is not so high, a fairly large number of elements are required to create a medium-power panel. After assembling the solar panel, the author still has a few garden lights left, but they are not enough for another solar panel. Therefore, the author decided to make a charger based on solar cells used in garden lamps.

Materials that the author used to create a solar charger:
1) a piece of plywood sheet
2) garden lanterns 4 pieces
3) Schottky diode
4) soldering iron and necessary consumables
5) AA or AAA rechargeable batteries.

Let's look at the main stages of creating and assembling this charger.
To begin with, the author calculated the approximate number of solar cells from the lamps based on their power and the power required to power the batteries. As a result, at least four garden lamps are needed to create a charger.

After this, the author began to disassemble the garden lanterns in order to remove the solar cells from them. You can also use existing battery holders, but the board and LED are not useful in this design.

If desired, you can carefully separate the solar cells from the cover of the garden lamp, since the elements are coated with a special resin, they are quite strong and, with the proper approach, will remain intact. Then place these elements in a plastic case. However, you should carry out such a procedure only if you need a beautiful appearance of the product; otherwise, it is permissible to use elements together with covers. The author did not add more work to himself and simply attached four solar cells along with covers to a sheet of plywood. After this, the author began to combine the elements into one design.

Below is a diagram of connecting the solar panel that will power the batteries:

As can be seen from the diagram, all elements are connected in parallel. To prevent the batteries from being discharged through the solar cells in low light conditions, the author installed a Schottky diode in the gap between the solar cells and the batteries. Thanks to this diode, the charger will accumulate energy in the sun and successfully store it at night.

The result was a charger made from 4 solar cells from garden lamps that power the batteries.

Almost everyone has solar lanterns for their garden. And they break often. And what? Buy new ones? Not at all!

I have been using solar-powered garden lanterns at my dacha for more than 5 years and I can confidently say that even the cheapest and most unreliable of them are very easy to bring back to life. The electrical circuit of a garden lantern is so simple that there seems to be nothing to break... if not for the poor build quality.

The most common fault is poor contact between the battery and the power container. I will not recommend the traditional method of hitting the flashlight, since the effect, if any, will be short-lived. The correct solution is to disassemble and clean the contacts of the power container and the battery poles.

The device itself is very simple. The dark piece of glass is a solar battery. The current it generates during daylight hours charges the battery that powers the LED during the dark hours. Turning on the lamp is controlled by a photocell and a microprocessor (in the simplest flashlights there are transistors).

LEDs are used to emit light; unlike incandescent lamps, they have a significantly lower current consumption and, therefore, can shine longer.

A photocell is a semiconductor device that converts light energy into electrical energy. Usually located in the same plane with the solar battery or they are made in one block.

The microprocessor can set different modes of operation of the lamps - for example, garlands of iridescent colors or flickering candles.

Next, I will list the most common breakdowns of solar-powered flashlights and how to fix them.

Poor contact between battery and power container

If the flashlight has not been used before, it is likely that the problem is the starter strip (the liner between the battery and the container) that has not been removed.

If the flashlight worked for some time, and then began to “mope”, it is worth cleaning the oxidized contacts of the container (say, with sandpaper).

It is possible that the battery is slightly offset in relation to the contacts of the container (and this can happen if the manufacturer saved money and used a non-standard container). In this case, you need to carefully pull out the negative spring, after first removing the battery. Additionally, I recommend securing the battery in the container using double-sided tape.

The battery is completely discharged

Either the battery has failed, or it was not charging, for example, because the flashlight is installed in the shade. In this case, you can check the voltage on the battery using a tester (the voltage should be between 1.1 and 1.4 V) and try to recharge the battery by placing a flashlight in a sunny place.

The solar lantern does not light up in the dark or lights up in both light and darkness

Perhaps the problem lies in the solder connections, and you will have to open the flashlight housing.

First of all, I check whether all the wires are in place, whether there are any breaks or tears, and also how well the soldering joints of the wires are made. If a green, blue or white coating in the form of salt crystals is visible in the soldering areas, it means that the soldering was performed with an active flux, and the soldering areas were not washed. This technology is used to speed up the assembly process, but the quality suffers greatly. In outdoor conditions, accelerated corrosion occurs at the soldering points, which worsens the contact or even dissolves the soldering.

I remove multi-colored “frost” on the printed circuit board inside the flashlight with a cotton pad soaked in acetone. I just wipe the board until the cotton wool is clean. Then I wash the board under running hot tap water, rubbing it with a hard brush to better rinse off any remaining flux, then dry it thoroughly. After this, as a rule, the flashlight starts working as usual. For example, a lamp that has passed a similar test is no longer

How many years has it been working successfully? True, I additionally treated all the body joints with a colorless sealant, since after disassembly and reassembly the seams might not fit together tightly.

The solar-powered flashlight stood in the sun all day, and with the onset of dusk it went out very quickly

Most likely, the battery is outdated; usually its service life is no more than 5 years. An old battery quickly loses its capacity, and a flashlight with such a battery will not shine for a long time.

Or maybe the protective cap over the solar battery has become cloudy (from time to time). This happens especially often in budget models, the cap of which is made of plexiglass. More expensive flashlights use regular glass, which lasts longer. If the plexiglass gets dirty, it can be washed using glass detergent. Just keep in mind that abrasive powders and pastes are contraindicated for plexiglass!

If the glass of the solar lantern body breaks

In this case, you can try to solve the problem by choosing a suitable replacement from scrap materials. So, I replaced the broken flashlight body with a piece of a plastic bottle. The color rendering may have changed a little, but the flashlight continues to serve.