Taking a 12V 60W street lamp as an example, according to the requirement of 7 hours of daily use and 4 consecutive rainy days, when applied in the Dezhou area of Shandong, combined with local lighting

First, calculate the current:

Current=60W ÷ 12V=5 A Calculate the battery capacity requirement:

Need to meet the lighting needs of continuous rainy days. (4 days plus overnight lighting before rainy days, totaling 5 days)

Battery=5A × 7h × (4+1) days=5A × 35h=175AH

In addition, to prevent overcharging and discharging of the battery, the battery is generally charged to around 90%; The remaining discharge is about 5% -20%.

So 185AH 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% -25% on the basis of 5A.

Calculate the peak demand (WP) for the battery panel:

The lighting time of street lights should be 7 hours per night (h);

★: The average daily effective light exposure time of the battery panel is 4.4 hours (h);

Relax the minimum reserve requirement of 25% for battery panels.

WP ÷ 17.6V=(5A × 7h × 125% ÷ 4.4h

WP ÷ 17.6V=9.33

WP=175 (W)