What is a solar street lamp?

Solar street lamp

Solar street lamps are powered by sunlight, which can be used at night without complicated and expensive pipeline laying. The layout of lamps can be adjusted at will, which is safe, energy-saving and pollution-free, stable and reliable, without manual operation, power saving and maintenance.

1. System composition

The system consists of solar cell module (including bracket), LED lamp holder, control box (with controller and storage battery) and lamp post. The light efficiency of Jinzhan solar panel reaches 1.27 w p/m2, which is very beneficial to the wind-resistant design of the system. In the lamp holder part, 1W white LED and 1W yellow LED are integrated on the printed circuit board and arranged in a dot matrix at a certain distance as a plane light source.

The control box is made of stainless steel, which is beautiful and durable; Maintenance-free lead-acid battery and charge-discharge controller are placed in the control box. The system adopts valve-controlled sealed lead-acid battery, which is also called "maintenance-free battery" because of its less maintenance, which is beneficial to reduce the maintenance cost of the system. The design of the charge and discharge controller considers the complete functions (including light control, time control, overcharge protection, overdischarge protection and reverse connection protection, etc.). ) and cost control to achieve high cost performance.

2. Working principle

The working principle of the system is simple. During the day, the solar panel made of photovoltaic effect receives solar radiation energy and converts it into electric energy, which is stored in the storage battery through the charge-discharge controller. At night, when the illumination gradually decreases to about 10lux and the open-circuit voltage of Jinzhan solar panel is about 4.5V, the charge-discharge controller detects this voltage value and acts, and the battery discharges the lamp holder. After the battery is discharged for 8.5 hours, the charge-discharge controller acts, and the battery is discharged. The main function of the charge-discharge controller is to protect the battery.

3. Design concept

Compared with general solar lighting, the design of Jinzhan solar street lamp has the same basic principle, but there are more links to consider. The following will take this Jinzhan solar LED high-power street lamp of Yangzhou Jinzhan Lighting Electric Appliance Co., Ltd. as an example, and analyze it from several aspects.

Selection of 1 jinzhan solar cell module

Design requirements: In Yangzhou area, the load input voltage is 24V, the power consumption is 34.5W, the working time is 8.5h every day, and the rainy days last for 7 days.

(1) The average radiation in Yangzhou in recent twenty years is 107.7 kcal/cm2, and the peak sunshine hours in Yangzhou is about 3.424 hours by simple calculation.

(2) Load daily electricity consumption = =12.2ah.

(3) The total charging current required for the solar module of Jinzhan =1.05×12.2× (3.424× 0.85) = 5.9a.

The shortest design day between two consecutive rainy days here is 20 days, 1.05 is the comprehensive loss coefficient of Jinzhan solar cell module system, and 0.85 is the charging efficiency of the battery.

(4) The minimum total power of Jinzhan solar module = 17.2× 5.9 = 102 W.

The peak output power is 1 10Wp, and a single standard battery module with 55Wp should be able to ensure the normal operation of the street lamp system in most cases of a year.

4. Battery selection

In the solar power supply system, the performance of the battery directly affects the comprehensive cost, operation quality and service life of the system. This scheme selects the latest energy storage colloidal battery jointly developed by our company and Institute of Metals, Chinese Academy of Sciences. Compared with ordinary lead-acid batteries, it has the following outstanding features in design and manufacturing technology:

Long service life, usually five to ten years.

The battery is more suitable for cyclic charging and discharging of energy storage batteries by adopting appropriate anode and cathode alloy formula and active material ratio.

The design of colloidal electrolyte can effectively inhibit the rust removal of active substances and the sulfation of electrode plates, thus delaying the performance degradation of the battery during use. And the deep charge-discharge cycle life of the battery is greatly prolonged.

Select the LED light source of the fourth generation lighting products.

Advantages of LED light source

? High luminous efficiency, low power consumption, long service life and low working temperature.

? Strong safety and reliability.

? Fast reaction speed, small unit volume and environmental protection.

? Under the same brightness, the power consumption is one-tenth of that of incandescent lamp and one-third of that of fluorescent lamp, but the service life is 50 times that of incandescent lamp and 20 times that of fluorescent lamp. It is the fourth generation lighting product after incandescent lamp, fluorescent lamp and gas discharge lamp.

The advent of a single high-power ultra-high brightness LED makes it possible for the LED application field to leap into the high-efficiency lighting source market, which will be one of the greatest inventions after Edison invented the incandescent lamp.

5. Battery assembly bracket

1) obliquity design

In order to make Jinzhan solar cell module receive as much solar radiation as possible in a year, we should choose an optimal inclination angle for Jinzhan solar cell module.

In recent years, the discussion about the optimal inclination angle of Jinzhan solar cell module has appeared in many academic journals. Street lamps are used in Yangzhou area. According to the related documents of this design, the inclination angle of Jinzhan solar cell module bracket is 16o.

2) Wind resistance design

In Jinzhan solar street lamp system, a structural problem that needs great attention is wind-resistant design. The wind-resistant design is mainly divided into two parts, one is the wind-resistant design of the battery module bracket, and the other is the wind-resistant design of the lamp post. The following are analyzed according to the above two blocks respectively. ⑴ Wind-resistant design of Jinzhan solar cell module bracket

According to the technical data of battery component manufacturers, the windward pressure that Jinzhan solar module can bear is 2700Pa. If the wind resistance coefficient is 27m/s (equivalent to 10 typhoon), according to inviscid fluid mechanics, the wind pressure borne by the battery module is only 365Pa. So the module itself can withstand the wind speed of 27m/s without being damaged. Therefore, the design focuses on the connection between the battery assembly bracket and the lamp post.

In the design of this street lamp system, the connection between the battery module bracket and the lamp post is fixed by bolts.

⑵ Wind-resistant design of lamp poles.

The parameters of the street lamp are as follows:

Panel inclination angle A = 16o lamp post height = 5m.

The weld width at the bottom of the lamp post is δ = 4mm, and the outer diameter of the lamp post is =168 mm..

The surface where the weld is located is the failure surface of the lamp post. The distance from the calculation point P of the resistance moment W on the damaged surface of the lamp pole to the action line of the load F on the upper panel of the lamp pole is

Pq = [5000+(168+6)/tan16o] × sin16o =1545mm =1.545m. Therefore, the effect of wind load on the damaged surface of light poles.

According to the design maximum allowable wind speed of 27m/s, the basic load of 2×30W solar street lamp board with double lamp caps is 730N. Considering the safety factor 1.3, F = 1.3×730 = 949N.

Therefore, m = f×1.545 = 949×1.545 =1466 n.m.

According to mathematical deduction, the resistance moment of annular failure surface w = π× (3R2δ+3Rδ 2+δ 3).

In the above formula, r is the inner diameter of the ring and δ is the width of the ring.

Resistance moment of sliding surface w = π× (3R2δ+3Rδ 2+δ 3)

=π×(3×842×4+3×84×42+43)= 88768 mm3

=88.768× 10-6 m3

Stress caused by wind load moment on sliding surface = M/W

= 1466/(88.768× 10-6)= 16.5× 106 pa = 16.5 Mpa < < 2 15 Mpa

Among them, 2 15 Mpa is the bending strength of Q235 steel.

Therefore, the weld width selected in the design meets the requirements. As long as the welding quality can be guaranteed, the wind resistance of the lamp post is no problem.

6. Controller

The main function of Jinzhan solar charge-discharge controller is to protect the battery. The basic functions must have the functions of overcharge protection, overdischarge protection, lighting control, time control and reverse connection prevention.

The general parameters of battery overcharge and overdischarge protection voltage are shown in the table.

1) When the battery voltage reaches the set value, change the state of the circuit.

In the choice of devices, there are some single-chip computers and some comparators, and there are many schemes, each with its own characteristics and advantages. The corresponding scheme should be selected according to the needs of the customer base, so I won't elaborate here.

2) surface treatment

This series of products adopt electrostatic coating's new technology, mainly FP professional building materials coatings, which can meet customers' requirements for product surface color and environmental harmony. At the same time, the product has high self-cleaning, strong corrosion resistance and aging resistance, and is suitable for any climatic environment. The processing technology is designed to coat on the basis of hot dip zinc, which greatly improves the product performance and meets the most stringent requirements of AAMA2605.2005, and other indicators meet or exceed the relevant requirements of GB.

summary

Chongqing Xiaoxingxing New Energy Technology Co., Ltd. independently develops and produces solar LED street lamps and solar (infinite) street lamps. In the design -R&D- production of solar LED street lamps, three common problems of solar street lamps (high power, fast LED light decay and more no power output) were broken, which seriously affected the cost and efficiency of street lamps. Greatly reducing the cost and prolonging the service life. Longer after-sales service and quality assurance make the promotion of solar street lamps and the cause of energy saving further developed. The following is the design scheme of our company's solar street lamp: the overall design basically considers all links; The peak wattage selection design and battery capacity selection design of photovoltaic modules adopt the most common design methods at present, and the design ideas are scientific; The wind-resistant design is analyzed from two parts: battery assembly bracket and lamp post, and the analysis is comprehensive; Surface treatment adopts the most advanced technology at present; The overall structure of the street lamp is simple and beautiful; The actual operation proves that all links cooperate well.

At present, the initial investment cost of photosynthetic solar LED lighting is still a big problem that puzzles our large-scale expansion. However, the light efficiency of solar cells is gradually improving, and the price will gradually decrease. Similarly, the light efficiency of LED in the market is also increasing rapidly, but the price is decreasing. Compared with renewable, clean and pollution-free solar energy and environmental protection and energy saving of LED, conventional fossil energy is increasingly tense, which will cause increasingly serious pollution to the environment after use. Therefore, starlight solar LED lighting, as a kind of outdoor lighting in the ascendant, will show us infinite vitality and broad prospects.

Solar street lamp:

Conventional configuration calculation in solar street lamp design

With the increasing shortage of traditional energy, the application of solar energy will be more and more extensive, especially in the field of solar power generation, which has developed into a mature sunrise industry in just a few years.

1: At present, the most important link that restricts the application of solar power generation is the price. Take a two-way solar street lamp as an example, with a two-way load of 60 watts. (If the effective illumination in the middle and lower reaches of the Yangtze River is 4.5h/ day, and the panel reserve is increased by 20% when it is discharged for 7 hours every night), the panel needs about160W, and the battery cost is about 180AH, which is much higher than the one-time investment cost of the whole street lamp, which has caused the main bottleneck in the application field of solar street lamps.

2. The service life of the battery should also be considered in the application of the whole street lamp system. Generally, the battery is guaranteed for three to five years, but it will not be fully charged after one year or even six months, and some actual charging rates may drop to about 50%, which will definitely affect normal lighting at night in continuous rainy days, so it is particularly important to choose a better battery.

3. Some engineers often choose LED lamps as the lighting of solar street lamps, but the quality layers of LED lamps are uneven, and LEDs with severe light attenuation may attenuate the illumination by 50% within half a year. Therefore, we must choose LED lamps with slow light decay, or choose electrodeless lamps and low-pressure sodium lamps.

4. The choice of controller is often ignored by engineers. The quality level of the controller is uneven. 12V/ 10A controller market price 200-300 yuan. Although it is the least valuable part of the whole street lamp system, it is a very important part. The quality of the controller directly affects the component life of the solar street lamp system and the procurement cost of the whole system. First of all, we should choose a controller with low power consumption, and the controller should work 24 hours a day. If you consume a lot of electricity, you will consume some electricity. It is best to choose a controller with power consumption below 1 MA. Secondly, to choose a controller with high charging efficiency, the controller of MCT charging mode can automatically track the maximum current of the panel, especially in winter or in the period of insufficient light, the efficiency of MCT charging mode is about 20% higher than others. Third, choose a controller with two ways to adjust power. The controller with power regulation has been widely popularized. At night, one or two roads can be automatically turned off to save electricity, and LED lights can adjust power. In addition to the above power-saving functions, we should also pay attention to the controller's protection function for batteries and other components. For example, the controller with trickle charging mode can protect the battery well and prolong its life. In addition, when setting the undervoltage protection value of the controller, try to adjust the undervoltage protection value to ≥ 1 1. 1V to prevent the battery from over-discharging.

5. Pay attention to anti-theft work in places far away from urban areas. Many engineering companies failed to carry out effective anti-theft due to negligence in construction, resulting in the theft of batteries, panels and other components, which not only affected normal lighting, but also caused unnecessary property losses. At present, most of the stolen engineering cases are batteries. Burying the batteries underground and pouring them with cement is an effective anti-theft measure. It is best to weld the reinforced battery box on the lamp post.

6. The controller is waterproof. Generally, the controller is installed in the lampshade and battery box, which will not get water. However, in practical engineering cases, the connecting wire of the controller terminal is often short-circuited because rainwater flows into the controller along the connecting wire. Therefore, during the construction, attention should be paid to bending the internal connecting wire into a U-shape and fixing it, and the external connecting wire can also be fixed into a U-shape, so that rainwater will not fall in and lead to a short circuit of the controller. In addition, waterproof glue can be painted at the interface of the inner and outer wires.

7. In many practical applications of solar street lamps, solar street lamps in many places can't meet the needs of normal lighting, especially in rainy days. In addition to using poor quality related components, another main reason is to blindly reduce the cost of components, not design and configure according to requirements, and lower the use standard of battery panels and batteries, so street lamps can not provide lighting in rainy days. The following formula is used to calculate the configuration of solar panels and batteries:

One: calculate the current first:

Such as: 12V battery system; 2 30W lamps, * * * 60W.

Current = 60w12v = 5a.

2. Calculate the battery capacity requirements:

For example, the cumulative lighting time of street lamps every night needs to be fully loaded for 7 hours (h);

(For example, at 8: 00 p.m., bus 1 1 closes at night, and bus 2 starts at 4: 30 a.m. and closes at 5: 30 a.m.)

Need to meet the lighting requirements for five consecutive rainy days. (5 days plus lighting the night before the rainy day, 6 days)

Battery = 5a× 7h× (5+ 1) days = 5a× 42h = 2 10ah.

In addition, in order to prevent the battery from overcharge and overdischarge, the battery is generally charged to about 90%; The remaining power is about 20%.

So 2 10AH is only about 70% of the real standard in application.

3. Calculate the peak demand (WP) of the battery panel;

The cumulative lighting time of street lamps should be 7 hours (h) per night;

★: The daily average effective illumination time of the panel is 4.5 hours (h);

At least relax the reserve of 20% of the panel demand.

WP÷ 17.4v =(5A×7h× 120%)÷4.5h

WP÷ 17.4V = 9.33

WP = 162 (width)

★: 4.5h is the sunshine coefficient near the middle and lower reaches of the Yangtze River.

In addition, in solar street lamp module, line loss, controller loss and power consumption of ballast or constant current source are all different, which may be about 5%-25% in practical application. Therefore, 162W is only a theoretical value and needs to be increased according to the actual situation.

Solar street lamp scheme:

Related component selection:

24VLED: Choose LED lighting, LED lamps have long service life, soft lighting and reasonable price, and can realize power adjustment when there are few pedestrians at night, which is conducive to saving electricity, thus reducing the configuration of battery panels and saving costs. 80- 105lm per watt, with annual light attenuation less than 5%;

12V battery (24V series): lead-acid maintenance-free battery is selected, with moderate price and stable performance, and solar street lamp is the first choice;

12V panel (string 24V): single crystal positive film with conversion rate above 15%;

24V controller: MCT charging mode with power adjustment function;

6M light pole (mainly beautiful in appearance, durable and cheap)

I. 40W Alternative Configuration I (General)

1, LED lamp, single channel, 40W, 24V system;

2. The local daily average effective light is calculated as 4h;

3. The daily discharge time is 10 hour (for example, from 7 pm to 5 am).

4, meet the continuous rainy days for 5 days (plus the electricity consumption of the night before the rainy day, 6 days).

Current = 40w ÷ 24v =1.67a.

Calculate the battery =1.67a×10h× (5+1) days.

= 1.67A × 60h= 100 AH

Reserve 20% capacity for battery charging and discharging; The actual current of street lamp is higher than 2A (plus 20%)

Loss, including constant current source, line loss, etc. )

Actual battery demand = = 100AH plus 20% reserved capacity and 20% loss.

100 ah÷80%× 120% = 150 ah

The actual battery is 24V/150AH, and two sets of 12V batteries are needed * * * 300AH.

Calculation panel:

1, LED lamp 40W, current:1.67a.

2. The daily discharge time is 10 hour (for example, from 7 pm to 5 am).

3. Reserve at least 20% of the panels.

4. The local effective light is calculated as 4 hours per day.

WP÷ 17.4v =( 1.67 a× 10h× 120%)÷4h

WP = 87W

The actual comprehensive loss of constant current source and line loss is about 20%.

Actual demand of battery panel = 87W× 120% = 104W.

The actual battery panel needs 24V/104W, so it needs two 12V battery panels * * * 208W.

Comprehensive component price: positive battery panel 208W, 38 yuan/watt, 7904 yuan.

Battery 300AH, 12 yuan /AH: 3600 yuan.

40W LED lamp: 2250 yuan.

Controller (only) 250 yuan

6m pole 1200 yuan

Total of this set of components: 15204 yuan.

Two. 40W alternative configuration II (with regulated power supply)

1, LED lamp, single channel, 40W, 24V system.

2. The local daily average effective light is calculated as 4h.

3. The discharge time through the controller every night is 10 hour (for example, from 7 pm to 5 am).

Adjusting the power of LED lamps in different periods to reduce the total power consumption is actually calculated by discharging for 7 hours every day.

(Example 1: 1 100% of the electricity comes from 7 pm, and 50% comes from 1 1 pm. Total: 7 hours)

(Example 2: 7: 00- 10: 30 is 100%, 10: 30-4: 30 is 50%, and 4: 30-5: 00 is 100%).

4, meet the continuous rainy days for 5 days (plus the electricity consumption of the night before the rainy day, 6 days).

Current = 40W ÷ 24V

= 1.67 A

Calculate the battery = 1.67A× 7h× (5+ 1) days.

= 1.67A × 42h

=70 AH

Reserve 20% capacity for battery charging and discharging; The actual current of street lamp is higher than 2A (plus 20%)

Loss, including constant current source, line loss, etc. )

Actual battery demand = =70AH plus 20% reserved capacity and 20% loss.

70AH÷80%× 120% = 105 ah

The actual battery is 24V/105AH, and two sets of 12V batteries are needed * * * 2 10AH.

Calculation panel:

1, LED lamp 40W, current:1.67a.

2. The daily discharge time is 10 hour, and the actual calculation is 7 hours after power adjustment (the power adjustment is the same as that of the battery).

3. Reserve at least 20% of the panels.

4. The local effective light is calculated as 4 hours per day.

WP÷ 17.4v =( 1.67 a×7h× 120%)÷4h

WP = 6 1W

The actual comprehensive loss of constant current source and line loss is about 20%.

Actual demand of battery panel = 6 1w× 120% = 73w.

The actual panel needs 24V /73W, so it needs two 12V panels * * * m: 146W.

Comprehensive component price: positive battery panel 146W,

Battery 2 10AH

40W LED lamp:

Controller (only)

6-meter pole

Three. 40W Option III (with regulated power supply and constant current)

The integrated controller of constant current, constant voltage and power regulation is adopted to reduce the system power consumption and component cost.

(The total loss of the system is actually reduced by about 20%, and the following calculation is 15%)

1, LED lamp, single channel, 40W, 24V system.

2. The local daily average effective light is calculated as 4h.

3. The discharge time through the controller every night is 10 hour (for example, from 7 pm to 5 am).

Adjusting the power of LED lamps in different periods to reduce the total power consumption is actually calculated by discharging for 7 hours every day.

(Example 1: 1 100% of the electricity comes from 7 pm, and 50% comes from 1 1 pm. Total: 7 hours)

(Example 2: 7: 00- 10: 30 is 100%, 10: 30-4: 30 is 50%, and 4: 30-5: 00 is 100%).

4, meet the continuous rainy days for 5 days (plus the electricity consumption of the night before the rainy day, 6 days).

Current = 40W ÷ 24V

= 1.67 A

Calculate the battery = 1.67A× 7h× (5+ 1) days.

= 1.67A × 42h

=70 AH

Reserve 20% capacity for battery charging and discharging; The actual current of street lamp is less than 1.75A (plus 5%).

Line loss, etc. )

Actual battery demand = =70AH plus 20% reserved capacity and 5% loss.

70AH ÷ 80% × 105% = 92AH