12 key points you must know when buying solar street light




 


1. Don't just look at the parameters only

When we buy solar street lights, we must not just look at the specifications advertised by the suppliers, because the battery that the supplier may advertise is 100Ah, but the actual product purchased is only 10Ah. Even with the same capacity, the available capacity of batteries of different grades is different. For the same solar street light, some supplier label 60W, and some may label 300W.


2. Cheap ≠ Cost-effective performance

People want to buy the cheapest products, but the cheap ones do not mean the most cost-effective. It also depends on the effect and longevity. For example:
The 10 years service life of a $300 lamp, the average annual cost is $30
The 1 year service life of a $100 lamp, the average annual cost is $100. If it is broken, there is a waste of time and energy cost, which is actually not worth.


3. Local temperature, latitude

The charging and discharging environment temperature of the LiFePO4 lithium battery is up to 65 degrees Celsius The charging and discharging environment temperature of the Ternary li-ion lithium battery is up to 50 degrees Celsius The maximum temperature of solar panels in summer can reach 90 degrees Celsius

Therefore, if you are in a hot area, such as
Africa: Algeria, South Africa, Angola, Morocco, Rwanda, Liberia, Ghana, Mauritius, Equatorial Guinea, Botswana, Gabon, Namibia, Tunisia, Cameroon, Nigeria
Middle East: Saudi Arabia, Kuwait, Israel, UAE, Oman, Qatar
Southeast Asia: Malaysia, Philippines
South America:Chile Mexico
You can only use LiFePO4 lithium batteries. Ternary batteries are easy to catch fire. And the heat dissipation performance of the lamp must be good, and the solar panel should not be in direct contact with the battery.

If you are at latitude greater than 15 degrees, the sun will have an inclination angle greater than 15 degrees with the ground. Try to consider solar street lights with adjustable solar panel angles. Solar street lights installed on both sides of the road should not have solar panels facing away the situation of sunlight.



 


4. The heat dissipation performance of the lamp

Every time the PN junction temperature of the LED chip increases by 10 degrees, the life span of the semiconductor device will decrease by multiples. It can be said that heat dissipation is an important guarantee for ensuring the life and quality of LED street lights. In this regard, bad manufacturers mainly use cutting corners to reduce costs, and this hazard cannot be found at the beginning of use, and it usually takes a period of time to find out. .

The increase in temperature has an impact on the calendar life and cycle life of lithium batteries. The effect of temperature on the life of lithium batteries conforms to the Arrhenius equation. The temperature of lithium batteries increases, and the reaction speed increases. Related research shows that the temperature of lithium batteries per liter At a temperature of 10°C, the degradation rate doubles. The same battery cell, when the remaining capacity is 90%, the output capacity at 25°C is 300kWh, while the output capacity at 35°C is only 163kWh. When the temperature rises by 10°C, the cycle life of the battery cell is reduced by nearly 50%.

It can be seen that temperature has a great influence on the cycle life of lithium batteries. Therefore, in the process of battery use, it is necessary to avoid long-term use of the battery under high temperature conditions, especially the high rate charge-discharge cycle of lithium batteries under high temperature conditions, which is also a main reason why the battery must be temperature controlled.


Therefore, the heat dissipation performance of the lamp must be considered. The solar panel is very hot when exposed to the sun. The solar panel must not be next to the battery and the LED light source.

The solar panel of the normal all-in-one/integrated solar street light is next to the battery, and it is a sealed space. The internal temperature can reach 70 degrees Celsius, which greatly damages the lifespan of the battery and the lamp beads. So we recommend the Foldable all-in-one/integrated solar street light


5. Four types of lithium batteries

Actual capacity of the battery
Some parameter table Ah looks very big, but in fact we bought Wh instead of Ah. Wh=Ah*V, we can’t just look at the capacity of Ah, but also the voltage.E.g:
90Ah, 3.2V actual battery capacity is 90Ah*3.2V=288Wh.
30Ah, 12.8V actual battery capacity is 30Ah*12.8V=384Wh

Available battery capacity
A deep charge and discharge will consume the capacity of the battery, so in order to protect the battery, the battery power is generally not reduced to the minimum. Different quality batteries have different pre-stored power ratios, for example:
Lead-acid batteries must reserve 50% of the power, so the depth of discharge is 50% of the actual capacity
The ternary battery must 30% of the power, so the depth of discharge is 70% of the actual capacity LiFePO4 Lithium battery only needs reserve 1% of power, so the depth of discharge can reach 99% of the actual capacity.

It can be seen that, in order to achieve the same available capacity, the ternary li-ion battery configuration must be higher than that of LiFePO4 lithium battery.

  • Class A LiFePO4 Lithium Battery

    2000 charge and discharge cycles

    10-15 years lifespan

    Good high temperature stability

    Depth of discharge up to 99%

  • Class B LiFePO4 Lithium Battery

    2000 charge and discharge cycles

    5-6 years lifespan

    Good high temperature stability

    Depth of discharge up to 99%

  • Class C Ternary li-ion lithium battery

    800 charge and discharge cycles

    3-4 years lifespan

    Easy to catch fire at high temperature

    Depth of discharge up to 70%

  • Class D Disassemble lithium battery

    300 charge and discharge cycles

    0-1 year lifespan

    Unstable

    Capacity decay Fast


The low-end solar street lights produced by manufacturers in Zhongshan city and Yangzhou city basically use disassembled batteries. In Shenzhen, there are a few quality manufacturers using B-type LiFePO4 lithium batteries, Shenzhen Moonlight Technology Co., Ltd uses A-Class LiFePO4 lithium batteries.


6. Solar panel

The solar panel not only depends on the size but also its conversion efficiency. Generally, the conversion efficiency of polycrystalline silicon solar panels is 12%, and the conversion efficiency of monocrystalline silicon solar panels is 15%-24%. The manufacturing cost of monocrystalline solar panels is higher than that of polycrystalline solar panels.
 

 
  • Conversion efficiency>21%

    Life span 25 years

    Decay rate after 10 years: 10%

    High-strength tempered glass, anti-freezing, anti-sandstorm

  • Conversion efficiency>16%-17%

    Lifespan of 15 years

    Decay rate after ten years: 80%

    Low-strength tempered glass

 


7. Sensor

Sensors are divided into microwave induction and infrared induction. Microwave induction can sense moving objects, and infrared induction can only sense temperature-bearing organisms.
 

 
  • Microwave Sensor

    Sensing distance 8-15m

    It has an effect on both people and cars

  • Infrared sensor

    Sensing distance 5-8m

    Can only sense people

 

8. LED light source

The light source looks dazzling does not mean high illuminance. With the same lumens, if the light-emitting area of the LED light source is smaller, it looks more dazzling, and human eyes will mistakenly think that it is brighter. There is a vertigo index in the street light. The higher the vertigo index of the street light, the less safe when driving .

 

For the same lumens, the smaller the angle of the lens, the more concentrated the area hitting the ground and the brighter the light, but at the same time the coverage of the light is smaller.

We should not only look at the wattage of LED light source, but also the light effect. The brightness is the wattage multiplied by the light effect.

 
  • 210 lm/w LED chip

    Attenuation rate of light after 5 years: 10%



  • 110 lm/w LED chip

    Attenuation rate of light after 5 years80%

 

9. The black lamp housing is too hot

The black lamps look high-end in the photos and indoors, but if they are installed outdoors, the background of the environment is blue sky, white clouds and green trees, and light-colored lamps are more coordinated with the environment.

 

Black is the most heat-absorbing, the temperature of the metal shell can reach up to 90 degrees Celsius under exposure, and high temperature will damage the battery and LED light source

  • Black shell temperature up to 82.2 degrees Celsius

  • The temperature of the silver casing is significantly lower


Therefore, we recommend to choose a silver shell as much as possible, which will not absorb heat or fade when placed outdoors.


 

10. Automatic wiper cleaning is not practical

Automatic windshield wipers are not unique to the solar street light factory. This solution comes from a company in Shandong that makes solar power stations. Any solar street light manufacturer can purchase a ready-made solar windshield wiper solution from this company.

 

It is not practical to clean the wiper automatically, because adding this function will greatly increase the cost. If the motor is broken and the wiper stops on the solar panel, the entire solar panel cannot absorb sunlight.

 

11. Poor effect of solar tower pole street light

Solar pole lights, solar panels are attached to the poles, and the effect of sunlight is very limited, and the absorption effect of solar energy is only 1/5 of ordinary solar panels. When the sun is at its maximum, that is, when the sun is directly above, the absorption effect of the pole solar panel is almost zero

 

12. Solar and wind energy hybrid street lights are a gimmick

Solar charging is the conversion of solar energy into electric energy, and the DC power is stepped down and converted to DC power to charge the battery. Wind energy charging is the conversion of mechanical energy into electrical energy, and the alternating current is stepped down to direct current to charge the battery.

 

The two energy conversion mechanisms are different, and the conversion equipment used is also different. If you use wind energy to charge the battery of the solar street light, it will impact the battery and cause the battery to decay quickly. Wind energy and solar energy should not be mixed. At present, the solar and wind energy hybrid street lights on the market generally only the solar works, and the battery is not connected to the wires of wind energy. Wind energy is only an imaginary project as a decoration.
 

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