Solar street lamp configuration calculation

Calculate current
For example: 12V battery system; Two 30W lamps with a total of 60 watts.
Current=60W ÷ 12V=5 A
Capacity calculation
For example, the lighting time of street lamps per night is 9.5 hours, and the actual full load lighting is 7 hours (h);
Example 1: 1-way LED lamp
(For example, 100% power is turned on at 7:30 pm, reduced to 50% power at 11:00 pm, 100% power is turned on after 4:00 am, and turned off at 5:00 am)
Example 2: 2-way non LED lamps (low pressure sodium lamp, electrodeless lamp, energy-saving lamp, etc.)
(For example, two routes are opened at 7:30 pm, one route is closed at 11:00 pm, two routes are opened at 4:00 am, and one route is closed at 5:00 am)
It is necessary to meet the lighting requirements for 5 consecutive rainy days. (5 days plus lighting overnight before rainy days, 6 days)
Battery=5A × 7h × (5+1) days
= 5A × 42h=210 AH
In addition, in order to prevent overcharging and discharging of the battery, the battery is generally charged to about 90%; The remaining discharge is about 5% - 20%. Therefore, 210AH is only about 70-85% of the true standard in application. In addition, according to the different loads, the actual loss should be measured. The actual working current is affected by constant current sources, ballasts, line losses, etc., which may increase by about 15% to 25% on the basis of 5A.
Peak Calculation
The cumulative lighting time of street lamps per night needs to be 7 hours (h);
★: The average daily effective lighting time for the battery panel is 4.5 hours (h);
A minimum allowance of 20% for battery panel requirements should be relaxed.
WP÷17.4V = （5A × 7h × 120%）÷ 4.5h
WP÷17.4V = 9.33
WP = 162（W）
★: 4.5h daily illumination time is the sunshine coefficient in the vicinity of the middle and lower reaches of the Yangtze River.
In addition, in solar street lamp components, line losses, controller losses, and power consumption of ballasts or constant current sources vary, and may range from about 15% to 25% in practical applications. Therefore, 162W is only a theoretical value, which should be increased according to the actual situation.