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Home > News > How to calculate the configuration of solar street lights

How to calculate the configuration of solar street lights


Hello, everyone. Recently, when I was on a business trip, I was often asked by some customers how this solar Street Light should calculate the lamp power, battery capacity, and photovoltaic panel power. What is the relationship between them?

split solar street light

I have also searched for related questions on Google, Quora, etc., but the result is not the answer to the question, or the copy and pasting of the posts that others have made, and the post itself is full of loopholes, the explanation is not directed to the answer or lacks theoretical basis, and does not have the slightest, none of them are operability.

So how to calculate the configuration of Solar Street Lights? We must first clarify three issues.

First, determine the power of the selected street lamp.

Second, determine the working hours of the street light.

Third, understand the local peak sun-hours (this can be an average of 4h according to worldwide peack sunshine-hours).

Now let's make it clear one by one. First, when we choose street lights, we need to consider the environment, height, brightness, etc. When we using. The requirements of different regions and customers are different. Since it is not the key points of this article, I will not repeat it here. (I will specifically introduce how to choose street lights later).

Here is an example for you. If the actual power of the selected street lamp is 30W, the customer requires the lamp to be turned on for 10 hours every night, and it can work continuously for 5 cloudy and rainy days.

solar street light installation

In this case, we generally offer two solutions to customers.

Option 1: Half-power, full-power combined power supply solution (also my most recommended solution)

What does that mean? That is, when the street lamp is working, the output of the current is adjusted by the controller, and the brightness is different in different time periods. For example: from 7pm to 11pm, full power 30W work during the 4 hours with heavy traffic, 4 hours and half power 15W work from 11pm to 3am, 4am-6am Work at full power or half power within 2 hours from the beginning of the day. (This time period is just an example. Different manufacturers can customize different controller schemes according to customer requirements). Then we can first calculate the power of the solar panels in this scheme.

solar panel power caculation

Where P is the power unit of the photovoltaic module is W, the unit of light source working time is h, and the coefficient 1.43 is the ratio of the peak working voltage of the solar cell module to the system working voltage, for example, the power supply or charging of the solar cell module for a 12V system The peak voltage is 17 to 17.5V, and the peak voltage of the solar cell module is 34 to 34.5V, etc. (just like a charger with a low voltage of 4.2V cannot charge a voltage of 12V, charging works The voltage must be higher than the system voltage). The unit of peak sunshine hours is h, and the two coefficients of 0.85 are the comprehensive coefficients of the Coulomb efficiency of the battery, the attenuation loss of the photovoltaic module, and the dust shielding.

For example, if the power of the light source is 30W, working 10 hours a day, and the local annual sunshine hours is 4 hours, the required photovoltaic module (solar panel) power is

unit of photovoltaic module caculation

The specific power selection needs to be carried out according to the specifications of the photovoltaic module, such as 125W.

With the solar panel power, let's calculate the battery capacity.

solar battery display

To calculate the battery capacity, first determine the type of battery selected (currently lithium iron phosphate batteries are generally used) and the number of storage days for the battery according to the local rainy weather conditions. The customer requires that it can work continuously for 5 rainy days. Calculated as follows:

Battery capacity caculation

The unit of battery capacity is Ah, the unit of load power is W, the unit of daily working time is h, and the unit of storage days is d (day). The depth of discharge is generally 0.5 to 0.7 depending on the type of battery; the unit of system voltage is Is V. For example, the power of the light source is 30W, 10 hours of work per day, and the storage time of the battery is 5 days. The required battery capacity is

Battery capacity 172Ah caculation

The above formula calculates the battery capacity required for full power for 10 hours, but our first scheme uses a combination of half power and full power, so the actual full power working time is 8 hours. Then choose the battery according to the voltage and capacity requirements of the system, such as choosing a 12V175Ah battery.

This solution is a relatively energy-saving solution, and it is currently recommended by many manufacturers.

Option 2: Full power supply solution (not recommended)

The second plan adopts the full power 10-hour working plan, from 7 pm to 6 am the next morning, then the required solar panels and battery capacity will increase, resulting in an increase in costs.

The PV module power required for scheme two is:

solar panel PV caculation

The battery capacity required for scheme two is:

Battery capacity 215Ah caculation

From the above formula, you can see that the solar panel power required for Option 2 is 148W, and the actual solar panel may be about 18V150W. The required battery capacity is 215Ah, and the actual battery may be about 220Ah. According to the current market, the cost may increase by about 20%.

In summary, I believe everyone should have a general understanding of how to calculate the configuration of Solar street lights. However, due to the current mixed market, the standard power of many manufacturers is not the same as the actual lamp power. In the next article, I will give you a glimpse of the "not enough W" problem of solar lamps. See you in the next issue!

In order to let you know more about solar photovoltaic products and provide better solar product solutions. I hope everyone interested in solar products can find solar products that suit them! Thank you for your attention.

Jiangmen Biaosheng Solar Energy Technology Co., Ltd. Business Type:Manufacturer , Organization , Service Product Range:Flood Lights , Garden Lights , Street Lights Products/Service:Solar lights , Solar flood lights , Solar street lights , Solar spot lights , Solar lights outdoor , Solar light LED Certificate:ISO14001 , ISO9001 , CB , CE , RoHS Company Address:NO.46 Keyuan Xi Road, Jianghai District, Jiangmen, Guangdong., Jiangmen, Guangdong, China Previous: Why people chosen LED solar flood lights for safety concerns

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