First, the solar cell used in the market:

Monocrystal solar cell: 125*125   A good buy on the market: 2.5W-2.7W

Polycrystalline solar cell: 156*156  A good buy on the market: 3W-4W

Cell conversion efficiency = wattage / area   Example: 2.5W / (125 * 125 * 0.99)

Example learning:

Watts conversion area: 2.5W/1000=0.00259

Area: 125*125=0.01546M2

Conversion efficiency: wattage / area = 0.00259 / 0.01546 = 0.1675 That is, the conversion efficiency of the 2.5 watt monocrystal solar cell can reach 16.8%.

Second, the solar panel voltage 12V (36 pieces) or 24V (72 pieces)

Example learning:

How to do the solar panel 120W/24V?

120W/72=1.67

1.67*2=3.3W

On the contrary, it can be inferred that it can be cut with a 3.3W polycrystalline solar cell 1/2: 3.3*1/2*72=119W (the size of the solar panel can be a bit error, with 5% floating)

Third, the solar panel operating voltage

Single cell voltage: 0.48V~0.5V

The normal 12V system panel operating voltage is 17.5V, and the 24V system panel operating voltage is about 35V; (0.48V~0.5V)*36=(17.28~18) (0.48V~0.5V)*72=(34.5~36)

Fourth, the calculation of the solar panel specifications:

Normal solar cell arrangement: 4*9 6*12

Example learning:

90W/12V monocrystal solar panel area calculation:

90W can be 2.5W*36; according to 4*9 arrangement, a single 2.5 watt solar panel is 125*125.

The width is: 4 * 125 = 500 + 45 (the gap between the solar cell pieces and the length of the frame) = 545

Length is: 9*125=1125+80 (gap between solar cells, junction box, and frame length)=1205

Summary: So the size of the 90W monocrystalline solar panel is 545 * 1205 size.

120W/24V polycrystalline solar panel area calculation:

120W/24V can be 3.3W (1/2 cut) * 72; according to 6 * 12 arrangement, a single solar cell is 156 * 156,

The width is: 6 * 156 = 936 + 45 (the gap between the battery pieces and the length of the frame) = 992

Length is: 12*156/2+80 (gap between solar cells, junction box, and frame length)=1020

Summary: So 120W polycrystalline solar panel size is 992 * 1020 size.