Monday, February 1, 2010

Solar Panels

Multi-crystalline (Polycrystalline) Solar Panels
A polycrystalline cell contains many crystals. It has similar life span to the monocrystalline cell type, but it has lower efficiency and cost per watt.

Mono-crystalline Solar Panels
A monocrystalline cell is made of a single crystal. Monocrystalline solar panels are high efficiency solar panels.

How much watt solar panel we need?
Example we want to power up 5 lights of 20 Watt and we need to use these 5 lights for 3 hours every day. Here first we get a total watt usage. Ptotal = 20 * 5 = 100W. Than we multiply 100 with 3 hours. Pdaily = 100 * 3 = 300W. We are going to use 300 watt daily. Let us say we are going to have complete sunshine 6 hours each day. Now we divide 300W with 6 hours, so we will get hourly power charge that we need Phourly = 300 / 6 = 50W. So we need a 50 watt solar panel. But it is recommended to always choose a panel some bigger then we need. Because when solar panel charge the battery so it is wasting some power on charging too.