When installing a solar power plant or installing a single panel, the choice of installation option is a very important point. The vast majority of owners of private households prefer the installation option on the roof of their buildings, and we will focus on this option in this article. We will cover the ground installation option in the next article.

As soon as a person begins the process of exploring the possibility of a potential installation of the solar system (power plant), among the first questions that he asks is - " Is my roof suitable for solar panels?” Solar panels (panels) are compatible with most roofing materials, but some of these materials are better suited for installing a solar power plant than others.

The roofs of buildings are generally divided into two types: sloping and flat.

Flat roofs are not very versatile. Usually this is a clean concrete surface or covered with various types of waterproofing: asphalt, roofing felt, metal profile, etc. Arrays of solar panels can easily be installed on a flat roof, but since such roofs are most often found on public buildings, we will consider installation on this type roofs in another article.

The construction industry, responding to consumer requests, has created a large number of roofing materials for sloping roofs, differing in composition (metal, ceramic, slate, soft rubber-plastic, flexible like roofing felt, etc.), in surface geometry (wave, meander , pseudo-tiled), according to the shape and size of single elements (sheets, flakes, rolls, etc.).

Accordingly, manufacturers of composite elements for mounting solar panels on the roof tried to cover the release of the maximum number of roof options and, using their products, make them available for installation of both arrays of solar modules and single solar panels.

To facilitate the design, almost all solar panel fasteners are made of aluminum. It must be said right away that a roof of a house that is competently designed in compliance with building codes, where the norm of 100 kg / m2 (for the Moscow region) is included in the estimated snow loads, of course, will calmly withstand an addition of 10-14 kg / m2 and, with proper installation, will preserve both the integrity of the roof and its thermal insulation properties.

Let's say right away that installing solar panels on roofs covered with short-lived roofing material is categorically Not recommended. Therefore, all roofs are covered with roofing felt, etc. for installing an array of solar modules not suitable.

The guides on which the photovoltaic panels are mounted are unified for several types of mounting clips (Fig. 1).

There are two types of clamps: end (Fig. 2,3) used to fasten the outer photovoltaic panels to the rails, and central (Fig. 4) used to fasten two solar panels to the rails at once, they differ only in a long leg, depending on the thickness of the solar frame batteries.

The butt connectors of the rails (Fig. 5) and the system grounding terminals (Fig. 6) are also unified, which combine all the fastening elements of panels with aluminum frames of photovoltaic panels into one circuit and its grounding.

The main variety is concentrated in the fastening elements of the guides to the roof. There are two options for fastening: fastening that does not violate the integrity of the roof, and fastenings that pierce the roofing material. Let's consider them in more detail on the example of metal roofs.

metal roofs, in which the connection of the cover elements is organized in the form of butt joints (folds) of various shapes refer to roofs, fastening to which is carried out without violating the integrity of the roof (Fig. 7,8,9,10).

Metal roofs, in which the geometry of the sheets corresponds to a wave, a meander or a tile, are roofs, fastening to which is carried out in violation of the integrity of the sheet (Fig. 11,12).

It must be said right away that the fasteners are equipped with special sealing gaskets that eliminate the very possibility of leakage.

Metal-roofed homes with well-insulated roofs have very low energy consumption and high structural strength, making metal-roofed homes excellent candidates for solar arrays.

Tiled roofing and Spanish tiled roofing, is also a good place to install solar panels. Standard penetrating fasteners allow you to install arrays of solar panels on tile roofs without compromising the integrity of the roofing material. At the same time, tiles can be not only cement and from other materials (Fig. 13 - 22)

The only disadvantage of a tiled roof is its heavy weight, but this does not affect the installation of solar panels.

Ethylene propylene dienterpolymer rubber (EPDM) coatings used both on flat roofs and sloping. The geometry of sloped roofs is flat. Solar installers working on EPDM roofs use a fastening system similar to that of a tiled roof, which means they typically do not drill holes in the roof.

Thermoplastic polyolefin (TPO) and polyvinyl chloride PVC coatings like EPDM roofs, they usually have a flat surface geometry and use a similar system of fixing the solar system to the roof (Fig. 21).

There are several types of roofs, the installation of solar panels on which will cause considerable difficulties.

Installers of solar panels really do not like to work on roofs covered with slate(flat or wavy). The fragility of this material during installation creates very great difficulties, and since it is necessary to drill holes in it during fastening, damage to the roof in places of discontinuity remains only a matter of time (Fig. 22).

Now a certain category of environmentally concerned citizens have begun to come into fashion wooden roofs. This type of roof, if the material during installation requires drilling holes in it to install solar panels unsuitable. They require specialized assemblies and equipment because installers cannot go onto the roof without damaging it.

All this means that installation of solar panels on slate and wooden roofs at the insistent desire of the customer is possible, but it costs much more.

The type of roof material you have on your home plays a big role in your home's suitability for a solar system, but it's not always the deciding factor. There are a few more questions you need to answer in order to determine if your home's roof is suitable for installing a solar system.

The orientation of the roof of your house to the cardinal points.

Solar panels are most effective when oriented strictly to the south side of the world (at least in the northern hemisphere).))) An easy way to find out how your roof is oriented and if it is good enough for installing solar panels is to look at the photos of your house on maps Yandex or Google. If you set the coordinate grid in the settings, it will tell you in which direction your roof is oriented. If you are not able to orient the panels to the true south, but only to the southeast and southwest, the panels will also work and with the help of certain techniques during installation and switching, you can achieve normal system efficiency. If your roof orientation isn't the best, you still have the option of installing the array of panels on the ground or on another building such as a gazebo, barn, workshop, bathhouse, garage, or carport.

Illumination of the roof at different times of the day and at different times of the year.

The shadow cast on the system affects the performance of the solar panels. Therefore, before installation, you will need to make a number of observations at different times of the day and at different times of the year in order to assess whether a shadow falls on your roof (and, as a result, on the solar system) and, depending on this, make a choice to install the system or not. Shade can come from other buildings, your own chimney, or the trees around your house. Your installer can help you evaluate the impact of the shadow in your particular situation. Of course, you won't be able to remove buildings or chimneys from your fireplace, but you can consider removing or trimming trees to create less shade.

Roof age.

A solar array has a lifespan of 25-40 years, so you will need to anticipate this long term to make sure your roof is in good condition and doesn't need to be replaced anytime soon. Therefore, we did not recommend previously not to install systems on a roof covered with roofing felt and other short-lived coatings.

If you are considering installing a solar system at the design stage of your home, then you should ask yourself: What shape and size will your roof be?”

It's easy, when installing panels on the roof, about 8-10 m2 of roof surface is required per 1 kW. Keep in mind that things like skylights, turrets, smoke vents and skylights will affect the amount of available space. Therefore, the more free surface of the south-facing roof you have at your disposal, the better.

And the last question of great importance when installing a solar system is "What is the pitch of your roof?" The influence of the angle of inclination of the panel to the horizon at different times of the year on the efficiency of the solar power plant, we considered in a previous article.

We considered the option of installing a solar system on a flat roof earlier, and this roof is good because you can set any angle of inclination of the panels to the horizon during installation.

If your roof has a slope, the optimal angle is from 30 to 40 degrees (in our latitudes up to 45 degrees, more north). Keep in mind that for the panels to self-clean with rain, they must be installed at an angle of at least 15 degrees to the horizontal. In winter, the maximum angle increases and can reach 70 degrees in our country (and this does not always prevent wet snow from sticking). All this must be taken into account when designing the angle of the roof slope of your house.

In this article, we consider the case of only private households, but where the owners of the house somewhat inevitably raise the question: "Who owns your roof?"

What to do if the roof of your house is not suitable for installing a solar panel system? Don't despair!

There are other options if your roof is not suitable for a solar panel system, including:

• Installation of a solar battery system on land related to your personal plot.
• Building a solar panel carport to power your home and provide shade for your car at the same time.
• Building a solar paneled balcony canopy while simultaneously powering your home and providing shade for you.
• If you have a greenhouse for agricultural exercises, then roofing it with transparent solar panels will provide both shade for crops grown in the hot summer and electricity for your home.

People have been thinking about environmentally friendly and cheap energy resources for a long time. Therefore, windmills and solar panels are becoming an alternative to energy based on the use of hydrocarbons. Heavy structures eventually transformed into elegant panels. They are used in everyday life, automotive industry, space exploration.

The device and operation of the modules

A flexible solar panel is designed as follows: a thin substrate is covered with a silicon semiconductor. The thickness of the coated panel is no more than 1 micron. The semiconductor is heated by the sun, as a result of which the electrons move in a given direction. Leads are mounted to the elements and a battery is formed. To operate such a mobile power plant, solar energy is used.

Large-sized, with low efficiency, solar panels are a thing of the past. Modern models do not require the maximum amount of sunlight, and the structures themselves have become light, flexible, mobile, they can be rolled up and taken with you on a hike.

At present, amorphous silicon is being replaced by cadmium sulfides and tellurides, copper-gallium and indium diselenides, and polymeric compounds.

To increase the efficiency, modern technologies allow the production of multilayer semiconductor structures. The cascade structure of the panel makes it possible to convert the reflected light several times, which brings their performance almost to crystalline options.

Despite the fact that the device looks quite simple, additional components are needed to supply current to the network:

• Battery that stores energy. It is needed for voltage fluctuations.
• An inverter that converts direct current to alternating current.
• System for adjusting the battery charge.

Distinctive characteristics

Flexible solar modules have their own characteristics:

• The thin pliable structure of the batteries makes it possible to use them on non-standard types of surfaces.
• They have a high level of optical absorption of photons, which increases their efficiency.
• Flexible batteries are able to work even in cloudy weather, which indicates high productive output.
• This type of energy is most relevant in hot climates, where solar modules receive the maximum amount of sunlight.
• Solar panels show especially high productivity at large solar complexes.

Advantages and disadvantages

A flexible solar panel, due to its mobility, has advantages over other types of batteries.

Its advantages include:

• The reliability of the product is ensured by measures that protect against mechanical destruction, exposure to moisture. Light weight and large area allows the panel to remain unharmed when falling from a height of many meters. Most designs are equipped with covers.
• The ultra-thin panel has a small mass, a 6-watt battery weighs less than 300 grams, while a crystalline one of the same parameters weighs 100 g more.
• The efficiency of film models is 15%, crystalline - 20%. But in terms of efficiency per body weight, the solar panel has advantages.

The disadvantages include the price, which exceeds the cost of a rigid battery. So far, not too much demand keeps the pricing policy. Gradually, the situation in this regard will improve.

Application

Devices that convert light into electrical current have long been used. Flexible solar panels make life easier for people in many areas, from the household level to space development.

In the architectural decoration of houses, flexible panels are mounted on the roofs and in the windows of buildings. Triplex glass with solar generation functionality collects light energy without disturbing the transparency of windows and creates a pleasant microclimate in the room. In rooms where triplex windows are installed, you can do without air conditioning.

Such glass is installed in educational institutions, trade pavilions, at public transport stops, it is used for outdoor pools and in greenhouses.

The small weight of the panels makes them in demand in the aircraft industry, they are equipped with electric cars, boats, balloons. Flexible structures have found their application in military affairs, shipbuilding, cinema, they are used by police officers and the Ministry of Emergency Situations.

The panels are mounted on any surface, so they are successfully used in everyday life.

The film battery can be found on watches, calculators, as stripes on clothes, on cases. Some modules are designed to be worn on bags and backpacks. Power bank with solar photocells allows you to charge phones, tablets, flashlights, cameras during expeditions and trips.

Photopanels based on amorphous silicon have found their application in space stations, given their low weight, they are easy to deliver to near-Earth orbit, and the energy intensity of such structures is five times higher than crystalline options. It is convenient to use solar panels on volumetric solar stations, where there is enough space for their placement.

Choice

One of the important selection criteria is the climatic conditions of the area in which the solar panels will be installed. The number of sunny days in a year and the length of the day itself are taken into account. Based on these data, the power of electricity that the battery should produce per hour or day is determined. For the northern regions, textured glass is suitable, it effectively copes with the work even on cloudy days. Modules made of micromorphic silicon do not require precise orientation to the sun, their total annual power exceeds other thin-film batteries. They are often chosen by residents of areas with low light.

When choosing a module for a home, you need to consider what electrical appliances will be in demand, whether the intended purchase will have enough power for them.

It is necessary to decide in advance on a place for solar panels and provide for a reserve area if you need to increase power.

When buying, the type of construction, material, thickness of the photocell, module manufacturer are taken into account - all this affects the price, quality and duration of work. It is not necessary to overpay for foreign brands, Russian-made modules have proven themselves well, focused on our climatic conditions.

To calculate the number of modules, it should be taken into account that a family of 4 people, on average, consumes 200–300 kW of electricity per month. Solar panels produce from one square meter from about 25 watts to 100 watts per day. To fully satisfy the house in the needs of electricity, you will need 30-40 sections. Equipping with solar panels will cost the family about 10 thousand dollars. Panels should be installed on the south side of the roof, where the maximum amount of sunlight falls.

To make a choice, you should understand which type of module is more suitable for the buyer:

• Monocrystalline solar cells cost $1.5 per watt. They are smaller and more efficient than other types of similar batteries. Their overall coverage takes up less space. Given the power and quality, it is better to make a choice in their favor. The only downside is the high cost.
• Polycrystalline batteries cost $1.3 per watt. In terms of power, they are inferior to single-crystal ones, but they are also priced cheaper. Budget opportunities attract buyers, besides, recent developments of such batteries have greatly brought their efficiency closer to single-crystal counterparts.

• Solar thin film panels have less power per square meter than previous models. The situation is evened out by the appearance on the market of micromorphic silicon modules. They generate a good total power for an annual period of time, they have proven themselves well in the work of the visible and infrared spectrum. For them, attachment to the sun's rays is not important. The battery life is 25 years. The modules have an inexpensive production technology, this has affected their cost - $ 1.2 per watt.
• Of great interest is the hybrid panel, as it generates thermal and electrical energy. The design combines a heat collector and elements of a photovoltaic battery.

A flexible solar panel is installed on the roof and other surfaces of cars, electric vehicles, velomobiles, boats, yachts and any other transport. Allows recharging of batteries without fuel consumption or charging from the mains. They are also used to generate electricity on stationary structures: roofs of buildings, canopies, small architectural forms - anywhere where bending of solar panels and / or low weight is required.

– Rated voltage: 5 v -72 v (optional)

– Maximum power: 5 w – 170 w (optional)

– The cost of 1 watt of power, when ordering 1 pc. flexible panel.: 3 – 3.6 usd

– Dimensions: on request, according to the table below

– Maximum electrical power obtained from 1 m2 of solar panel: 160 w

– Weight of 1 m2 of solar panel: 3 – 4 kg. (depending on thickness)

– solar panel thickness 2.5 – 3 mm (it is possible to manufacture solar panels with a thickness of 1.5 mm)

– Solar panel body material: plastic

– Maximum bending angle: 30 degrees at a distance of 30 cm.

– Solar panel type: monocrystalline

– Maximum solar panel efficiency: 18%

– Solar panel lifetime: 10 years (before power reduction by 20%)

– C panel fixing methods:

- using double-sided tape;

- using screws or other fasteners

Flexible photovoltaic panels are available on request to provide:

– required location of the controller (on the outside or inside of the panel)

Standard sizes of solar panels, with indication of their characteristics, are presented in the table below. If none of the sizing options are suitable for efficient use of the space planned for their installation, custom-made panels can be considered.

For maximum convenience of our customers, controllers are also manufactured with the required output voltage.

The maximum power of one flexible solar panel is limited to 170 watts. If more power is required, it is collected from several solar panels.

Please check with the manager for the deadline for the production of flexible solar panels.

Warranty 2 years.

The advantage of flexible solar panels is already in their name - flexibility. Thanks to the ability to bend solar panels to the profile of the roof of a car, boat, airplane wing or porch canopy, huge opportunities open up for converting solar energy into electrical energy - where it was previously difficult to do.

Low specific gravity per unit area, thickness of only 3 mm and high efficiency of 18%, which is not inferior to conventional monocrystalline solar panels, makes flexible solar panels from TM Volta bikes, produced using the latest technologies, the most advantageous offer on the market in terms of price / quality ratio.

Installation of flexible solar panels is extremely simple: with glue, double-sided tape, and in those places where it is possible, even with screws.

Use every square meter of your transport or buildings to your advantage - converting sunlight into free electricity for movement, business, comfort!

DIY electric car: Flexible solar panel for cars

Nav view search Product catalog Flexible solar panel for cars Flexible solar panel for rooftop and other

Sphelar Flexible Solar Panels

Continuing the topic of energy, I present to your attention the revolutionary concept of spherical solar cells, which were created by the Japanese company Kyosemi. Flexible solar panels, due to their special shape, are able to capture sunlight from all directions.

Conventional flat panel solar panels are easy to design and manufacture, but the efficiency of flat panel solar cells depends on their position relative to the sun. Whereas, Sphelar spherical solar cells are much more efficient and require less production costs. Sphelar's flexible solar panels are designed for mobile phone batteries.

A spherical shape is a matrix on which solar cells with a size of about 2 mm are placed. small size allows you to place the elements in different positions, which means that sunlight will be absorbed constantly. There is no need to adjust to the position of the sun. In addition, flexible Sphelar solar panels are able to collect sunlight even in the morning and evening hours. The surface on which the solar cells are placed is flexible, so if necessary, the flexible solar cell can be bent as desired.

Flexible solar panel from Chicago designers became a Kickstarter hit in 2 days

Chicago-based YOLK, USA, is raising funds for "solar paper" that fully charges iPhone batteries in 2.5 hours.

Solar Paper is a very thin solar panel that fits easily between the pages of a notepad or exercise book. Despite its thinness, the portable solar charger is capable of generating up to 10W of power.

On a nice sunny day, Solar Paper charges an iPhone 6 in 2.5 hours, which is the equivalent of a 5V-2A mains charger. The device is suitable for charging any gadget via a USB cable.

The dimensions of the "leaf" are 9x19x1.1 cm, and the weight is 120 gr. The thickness of the panel is only 1.5 mm.

Solar Paper uses modular panels connected to each other using built-in magnets. In total, you can connect up to four panels with a power of 2.5W each. Four panels will provide the smartphone with up to 10W of energy via a USB connection.

In addition, Solar Paper is programmed to automatically resume charging when sufficient sunlight is detected, which is very useful on cloudy days.

The solar panel is equipped with an LCD display that displays the current supplied to the connected device. This allows you to choose the optimal position and angle of the Solar Paper for charging, depending on the weather conditions.

The fundraising campaign on Kickstarter, in fact, ended in 2 days, when the $50,000 required for launching into production were collected.

At the time of writing, the developers have raised more than $229,000. The first batch of solar chargers will be delivered in September 2015.

The Solar Paper version for 5W of energy costs $69, for 10W (4 solar panels) - $450.

Chicago-based Flexible Solar Panel Hits Kickstarter in 2 Days - Blog

Chicago-based YOLK, USA, is raising funds for "solar paper" that fully charges iPhone batteries in 2.5 hours. Solar Paper is a very thin solar panel that easily fits…

I want to start the review by explaining why I need it. I already have a small 7 watt solar panel. Over time, I will post her review here.

To be honest, I didn’t have any wild need for such a panel. Basically a wishlist.

I wanted to expand autonomy, the ability to use flashlights / cameras / telephones / walkie-talkies / zhps to the whole group in the alloy without fear, and frantically not counting whether there will be enough Akum. I did not want to lug a bucket of lithium for 3 kayaks for 2 weeks.

I wanted to go online at the dacha despite power outages, etc.

A small 7-watt panel could not provide all this. Let's see how the new one does.

True, I, as in the saying "prepared a sleigh in the summer" in the sense of a solar panel in the winter. But you can take a photo and some kind of test even now.

Side panel with characteristics of different panel sizes

Characteristics closer

Part of the box describing how to connect the connectors

Now we open.

First, the instructions - the printing is disgusting. Printed on a half-dead printer information from the site on both sides of the leaflet

Then shake the accessories out of the box

Long wire with terminals on the end

And a wire with a car cigarette lighter connector

The connector itself gives the impression of being monolithic. There is a latch, rubber seal for waterproof. The instructions say something like marine-grade. Full waterproof. By the way, the panel itself is also not afraid of water.

Now let's get the panel itself out of the box. It is quite light at about 450 grams. Rolled up. and intercepted with Velcro

The panel is made of soft, pleasant to the touch plastic. Eyelets for fastening in all corners

The structure of solar cells is honeycomb

Now expand the panel. It's about 1100 in length.

I bring the panel to the window. and take measurements.

First, voltage.

If my memory is correct, then you need to multiply 21.7 and 0.3 and you get 6.5 watts. Half of the declared power. I don't think it's bad for winter. In summer, he must give all 14.

I hook up a lithium charger. Charging started.

In general, I really liked the panel. Sturdy (in the commercial it was shot 5 times with small things and it continued to work), compact, waterproof (this is important in alloys) and powerful enough to power devices up to the size of a laptop. I also forgot to write that flexible solar cells practically do not degrade over time.

Of course, you can’t really attach it to a backpack, but it’s a great option for kayaks, a stationary camp, a hunting hut.

Well, in case of a global blackout, neighbors can charge their flashlights for money.

In short, I'm happy.

UPD 07/28/13
panel has shown itself successfully in

Flexible solar panels have become a real boon for travel enthusiasts and just for those who like to be independent of traditional outlets. Of course, you can’t light a house with such elements, you can’t heat it, and you won’t be able to get a lot of energy at all. But is it necessary to strive for this? After all, the purpose of such batteries is comfort for a tourist, that is, a person who does not have temporary permanent housing. Therefore, charging a laptop, mobile phone or tablet is the task of portable solar cells.

Advantages and disadvantages

• Weight. This indicator is undoubtedly the most important advantage for flexible elements. You can compare different models, but basically the difference will be visible at about 30%, and this is already enough to talk about comfort. For example, tourists know this firsthand, every thing in a backpack or on it should have as little weight as possible. On a hike, every 100 grams become noticeable, and to understand this, it is enough to walk ten kilometers on uneven terrain. The issue of weight-to-power ratio is solved by flexible solar panels trivially - the more weight, the higher the power. For example, a 3W model weighs 149 grams, while a 6W model weighs 284 grams. To be fair, a 6 W solid solar panel weighs 390 grams.
• Size. Here, flexible batteries lose to their solid counterparts. If we take the same power of 6 W, then the size of the flexible element will be about 1.5 square meters, while the solid version will have an area of ​​\u200b\u200b0.9 square meters. Of course, the undeniable advantage of flexible batteries is their ability to be folded, but this is not always such a high figure. Especially when it comes to hiking, where you have to carry everything on yourself.
• Efficiency. The exact numbers are hard to figure out. Firstly, manufacturers often overestimate the power of their product, and secondly, even elements of the same manufacturer and the same batch can differ significantly in power.

On average, we can talk about such indicators: the efficiency of solid batteries is approximately 18-20%, while flexible batteries have an efficiency of about 12-15%. But if you make a conversion per unit weight, then flexible batteries will cost about twice as much.

• Reliability. The production technology allows you not to worry too much about this indicator. Typically, the flexible elements are sewn into a sheath that is immune to relatively high loads. The water resistance of flexible batteries is also high. Once exposed to rain, the batteries will not show problems in operation after it ends. The shock resistance of flexible batteries is quite high, due to their light weight and springiness during contact with the surface when dropped. If you believe the reviews of tourists, then even after falling on stones from a height of about 10 meters, flexible batteries continued to work. Of course, such cases can be individual. It is enough to draw an analogy with a person, when it is enough for one to fall in a room and break three ribs and a collarbone, and someone falls from the second floor and slowly continues to go somewhere. Scratches on the surface when falling elements may remain. Such scratches are not able to affect the overall operation, but if there are a large number of them, the power may decrease slightly.
• Price. Flexible batteries cost more than their rigid counterparts due to their greater compactness. You will have to pay a little more for the advantages of flexible batteries and in some cases for a brand name.

What to look for when buying and during operation

• When buying, you need to pay attention to the current strength. Since most often you will need to charge mobile devices, a current of 0.5A will be enough. True, if there is a lot of sunlight.
• Mounting of solar flexible panel can be different. Some panels are attached with suction cups, which makes their installation on smooth surfaces very convenient. For example, on the roof of a car or glass showcase. Without exception, all models are equipped with small holes in the covers, so that it is convenient to attach to a backpack.
• When using, one should not forget that the most optimal position of the flexible element will be a perpendicular slope to the sun's rays. You also need not to use the battery through the glass - up to 35% of power is lost.
• Efficiency for elements of this type is an argument on which unscrupulous sellers and manufacturers often speculate. The latest Swiss innovation has an efficiency of 17.7%. So, if you have to hear the assurances of the seller about the efficiency of 25%, or even all 50%, you can safely turn around - they want to sell you something that has not yet been invented in the world.
• To date, many offices and firms have appeared that produce flexible elements to order. In such institutions, you can choose the appropriate power and size, and, accordingly, the weight of the battery.

Flexible batteries that run on sunlight are indeed a very curious and promising novelty. Most likely, such elements will fill the market very soon, as there is a general decrease in prices for this product. Big and small, wide and narrow, for more or less power - they all require money when buying. Then they work completely free of charge and for several decades.