Configuration and connection of Teejoin solar panels and batteries, and calculation formulas
How to connect solar panels and batteries
When connecting solar cells and batteries, it is better to use a photovoltaic charge controller, which can control the output voltage of the solar cells and protect the batteries from being overcharged, and also prevent the backflow of electricity from the batteries when the solar cells are not generating electricity at night.
Connection is as follows:
Solar cells ---- photovoltaic controller --- battery --- DC load.
In this case, the power used by the load will give priority to the direct use of solar cells, and the remaining charged to the battery; on the contrary, if this solar cell is not enough power, it will take power from the battery at the same time.
Solar panel and battery configuration calculation formula
One: First calculate the current:
Such as: 12V battery system; 2 lights of 30W, a total of 60 watts. Current = 60W ÷ 12V = 5 A
Second: Calculate the battery capacity requirements:
Such as: street lighting 9.5 hours per night, the actual full load lighting for 7 hours (h); Example 1: 1 road LED lights
(such as 7:30 pm open 100% power, night 11:00 pm down to 50% power, 4:00 am then 100% power, 5:00 am off)
Example 2: 2-way non-LED lamps (low-pressure sodium lamps, induction lamps, energy-saving lamps, etc.)
(such as 7:30 p.m. two-way open, night 11:00 closed 1 way, 4:00 a.m. open 2 way, 5:00 a.m. closed)
Need to meet the lighting needs of 5 days of continuous cloudy and rainy days. (5 days plus the night before the rainy day lighting, counting 6 days) Battery = 5A &TImes; 7h &TImes; (5 + 1) days = 5A &TImes; 42h = 210 AH
In addition, in order to prevent the battery from being overcharged and overdischarged, the battery is generally charged to about 90% and discharged to about 5%-20%.
So 210AH is only about 70%-85% of the real standard in the application. In addition, according to the different loads, the actual loss is measured.
The actual operating current is affected by constant current source, ballast, line loss, etc., may be increased by about 15%-25% on the basis of 5A.
III: Calculate the peak demand (WP) of the battery panel: the accumulated lighting time of the street light needs to be 7 hours (h) per night;
★: The average time the panel receives effective light is 4.5 hours (h) per day; Z less relaxation of the 20% allowance for the panel demand.
WP ÷ 17.4V ＝ (5A &TImes; 7h × 120%) ÷ 4.5h WP ÷ 17.4V ＝ 9.33 WP = 162 (W)
★ : 4.5h daily light time is the sunshine factor for the area near the middle and lower reaches of Yangtze River.
In addition, in solar street light components, the line loss, controller loss, and ballast or constant current source power consumption varies, and may be around 15%-25% in actual application. Therefore, 162W is only a theoretical value, which needs to be increased according to the actual situation.
