How to calculate solar panel capacity, batterty, lighting area of solar lights

In the design process and selection of suitable products for solar street lighting projects, accurate calculations of lithium storage battery capacity, solar panel power, and lamp post height are crucial for optimizing efficiency and costs. This calculation also relies on the power of the devices to assess the quality and cost-effectiveness of solar lights.

General structure of solar streetlights

Solar streetlights are commonly used in illuminating pathways in residential areas, resorts, rural road projects, smart urban transportation, and public facilities. These lights operate fully automatically, requiring no grid connection, saving on wiring costs and road excavation. Installation is as simple as plugging in the pole and mounting the light. A typical solar street lighting system includes the following components:

LED lights: Consisting of a light housing and modules containing LED chips. The housing is often made of aluminum for robustness and quick heat dissipation. High-performance LED chips from reputable brands like Bridgelux (USA), Philips (Netherlands), or Osram (Germany) are used for high luminous efficiency and durability exceeding 12 years.

Solar panels: Responsible for absorbing sunlight to charge the storage battery. There are two types: mono (monocrystalline silicon) or poly (polycrystalline). Mono panels are commonly used for better light absorption and a lifespan exceeding 25 years. Panels can be integrated with LED lights or installed separately, allowing adjustable angles.

Storage battery: Various types include lead-acid gel battery, Lithium LiFePo4 battery, 1865 Li-ion Battery, installed inside the light or externally. Advanced technology often employs Lithium iron phosphate (LiFePo4) batteries with deep charge and discharge capabilities and a lifespan of up to 8 years.

Controller: Manages the charge/discharge for the storage battery, adjusts brightness, monitors operations, and extends the lifespan of the battery and light. Intelligent control capabilities enable the light to automatically turn on in the dark and off in daylight.

Lamp post: Typically made of steel, hot-dip galvanized to adapt to various environments and installation areas.

Calculating lamp post height and illuminated area

** Calculating lamp post height:

To determine the lamp post height, factors such as light power or road width and the installation pattern for each project need to be considered.

+ If considering the power of solar streetlights, the following table provides suggested lamp post heights:

Note: Calculations are based on lights using LED chips with luminous efficiency of 170lm/W.

Light Power	Lamp Post Height
10 – 20W	4m
20 – 30W	6m
40 – 60W	8m
50 – 80W	10m
60 – 100W	11m

(The suggested specifications table from Sokoyo)

+ If considering road width and installation pattern, three common patterns are: single-side installation, double-side installation, and zigzag installation.

Installation pattern	Road width	Lamp post height
Single-side installation	N	N
Double-side installation	N	N / 2
Zigzag installation	N	N x 1,5

(Formulas provided by Sokoyo)

Example: For a road width of 12m with double-side installation, the lamp post height can be chosen as 12 / 2 = 6m.

Additionally, the distance between lamp posts can be calculated using the formula:

Distance between 2 lamp posts = Lamp post height x 3

Example: If the lamp post height is 6m, then the distance between 2 lamp posts would be 6 x 3 = 18m.

** Calculating illuminated area:

The formula for calculating the illuminated area is Illuminated area = N x 3N

Where N is the lamp post height

Example: For a 60W light with a lamp post height of 8m, the illuminated area would be 8 x 3 x 8 = 192m².

Note:

This calculation is relatively indicative as the illuminated area depends on factors like lamp post height, bat wing light distribution, etc.

Calculating storage battery capacity and solar panel power

To understand how to calculate storage battery capacity and solar panel power for specific projects, let’s consider a typical example:

**Calculating storage battery capacity:

Example: A customer requires lighting as follows:
– Using a 60W solar light
– Illuminating for 12 hours each night, with brightness modes as follows:

• First 0.5 hours at 20% brightness (18:00 – 18:30)
• Next 1 hour at 100% brightness (18:30 – 19:30)
• Next 3 hours at 50% brightness (19:30 – 22:30)
• Last 7.5 hours at 20% brightness (22:30 – 6:00)

– Reserve time for extended cloudy or sunless days is 3 days.

With these parameters, the calculated storage battery capacity with a 90% depth of discharge for the LiFePo4 battery is:

Storage battery capacity = (60W x 0,5h x 20% + 60W x 1h x 100% + 60W x 3h x 50% + 60W x 7,5h x 20%) x 3 / 90% = 820Wh. (Storage battery capacity is approximately 14 times higher than the light power).

** Calculating solar panel power:

To determine the suitable power of the solar panel, additional parameters are required:
– Average sunlight hours in Vietnam: 4 hours/day
– Power loss on the solar panel due to dust accumulation: 65%
– Storage battery reserve capacity: 20%
– The solar panel power is calculated as follows:

Solar panel power = (60W x 0,5h x 20% + 60W x 1h x 100% + 60W x 3h x 50% + 60W x 7,5h x 20%) / 65% / 4h x (1 + 20%) = 114W (Solar panel power is approximately 2 times higher than the light power).

Note:
– The above formulas apply to default lighting modes.
– Depending on specific needs, usage purposes, lighting modes, weather conditions, and radiation, storage battery capacity and solar panel power can be selected case by case (only applicable to SPLIT-type lights).

After understanding how to calculate storage battery capacity, solar panel power, lamp post height, and illuminated area, customers can refer to the technical specifications of a Sokoyo solar light.

Product Introduction: NOVA – All-in-One Solar Street Light

	Product Code	KY-Y-YF-004
	Rated Power	60W
	System Voltage	DC 12V
	Lithium Battery	864WH
	Solar Panel	Mono Panel: 18V/130W (505×1330mm）
	LED Chip	LUMILEDS3030/5050
	Light Distribution Type	Bat Wing Light Distribution (150°x75°)
	LED Chip Efficiency	170LM/W
	Color Temperature	3000K/4000K/5700K/6500K
	Color Rendering Index	Ra≥70
	IP Protection Level	IP65
	IK Protection Level	IK08
	Operating Temperature	-10℃~+60℃
	Weight	24kg
	LED Lifespan	≥50000H
	Controller	SES120
	Pole Diameter	φ76mm
	Light Size	1357x518x173mm
	Package Size	1410x580x150mm
	Installation Height	7 m / 8 m / 9 m

LED Chip

• Brand: Lumiled Philips (Netherlands)
• LED Chip Efficiency: 170lm/W
• LED Chip Lifespan: Approximately 50.000h (about 12-15 years)
• Each LED chip comes with its own bat wing lens

Battery

• Battery Type: Lithium LiFePO4
• Battery Capacity: 864Wh, 14 times the light power, ensuring lighting for 3 days in adverse weather conditions
• Up to 2,000 deep discharge cycles, safe and reliable, no explosion. Lifespan approximately 5-8 years

Solar Panel

• Panel Type: Mono
• Cell Efficiency: Up to 21%
• Power: 130Wp, more than 2.2 times the light power, ensuring rapid energy absorption for battery charging

Smart Controller

• Intelligent control over lighting duration, monitoring battery charge and discharge levels to extend lifespan, overload protection, high charging efficiency, maximizing solar panel performance. Automatically turns on the light in the dark and off in daylight.
• Can connect to IoT management and monitoring systems.

Motion Sensor

• Currently, products utilize microwave sensor technology (older PIR sensor technology) for quick motion detection and instant brightness adjustment.

NOVA Solar Light is fully compliant with CO and CQ standards; LED chip test reports; CE, RoHS, IEC product certifications, and more. Additionally, it comes with an official warranty policy in Vietnam, offering a 3-5 year extended warranty.

With the information shared by DAT Solar, it is hoped that you can calculate the parameters for storage battery capacity, solar panel power, and lamp post height to choose suitable solar street lighting products for your project.

If you still have questions about the product or lighting solutions, please contact the hotline at 1800 6567 (free call) for 24/7 consultation and support.