How to configure solar street lights to be reasonable?
一: First calculate the current:
Such as: 12V battery system; 2 30W lamps, 60 watts in total.
Current＝60W÷12V＝5A
2: Calculate the battery capacity requirement:
Such as: the accumulated lighting time of street lights every night needs to be 7 hours (h) at full load;
(such as opening at 8:00 in the evening, closing 1 road at 11:30 in the evening, opening 2 roads at 4:30 in the morning, and closing at 5:30 in the morning)
needs to meet the lighting needs of continuous rainy days for 5 days. (5 days plus the lighting of the night before rainy days, totaling 6 days)
Battery=5A×7h×(5+1) days=5A×42h=210AH
In addition, in order to prevent the battery from overcharging and over-discharging, the battery is generally charged to about 90%; the discharge is left about 20%.
So 210AH is only about 70% of the real standard in the application.
3: Calculate the peak demand (WP) of solar panels:
The accumulated lighting time of street lights needs to be 7 hours (h) per night;
★: The solar panel receives an average effective light time of 4.5 hours per day (h);
Relax at least 20% of the reserve for solar panels.
WP÷17.4V=(5A×7h×120%)÷4.5h
WP÷17.4V＝9.33
WP＝162(W)
★: The 4.5h daily sunshine duration is the sunshine coefficient in the vicinity of the middle and lower reaches of the Yangtze River.
In addition, in solar street lamp components, the line loss, the loss of the controller, and the power consumption of the ballast or constant current source are different. In actual applications, it may be about 5%-25%. So 162W is only a theoretical value, and it needs to be increased according to actual conditions.
