One: First calculate the current: Example: 12V battery system; 2 lamps of 30W, a total of 60 watts. Current = 60W ÷ 12V = 5A Two: Calculate the battery capacity requirements: For example, the cumulative lighting time of street lamps needs to be 7 hours (h) at full load; (If it is open at 8:00 in the evening, 1 in the night at 11:30, 2 in the morning at 4:30, and closed at 5:30 in the morning) Need to meet the lighting needs of 5 days in continuous rainy days. (5 days plus one night before the rainy days, 6 days) Battery = 5A × 7h × (5 + 1) days = 5A × 42h = 210AH In addition, in order to prevent overcharging and overdischarging of the battery, the battery is generally charged to about 90%; the remaining discharge is about 20%. So [FS:PAGE]210AH is only about 70% of the real standard in the application. Three: Calculate the peak demand (WP) of the panel: The cumulative lighting time of street lamps per night needs to be 7 hours (h); ★: The average effective time of the panel is 4.5 hours (h) per day; at least a 20% reserve for the panel is relaxed. WP÷17.4V=(5A×7h×120%)÷4.5h WP÷17.4V=9.33 WP=162(W) ★: 4.5h daily light time is the sunshine coefficient in the vicinity of the middle and lower reaches of the Yangtze River. The middle and upper reaches of the Yangtze River are generally 5h. In addition, in the solar street light module, the line loss, controller loss, and power consumption of the ballast or constant current source are different, and may be in the range of 5% to 25% in practical applications. Therefore, 162W is only a theoretical value, and it is necessary to increase or decrease the configuration parameters according to the actual situation. Agriculture Staple,604 Fixing Nail,Hardware Staples Nail,Custom Agricultural Use Nail Zhejiang Best Nail Industrial Co., Ltd. , https://www.beststaple.com