Installing Solar PV Panels

Sizes
Solar PV panels come in two main sizes, depending on the number of solar cells they are made from. 60-cell panels are about 1.6m tall and 1m wide, 72-cell panels area about 2m tall and 1m wide.

Larger panels are not better because they are bigger. They generate the same energy on the same area of roof as smaller panels. Choosing a solar PV panel size depends on which size will best fit the available roof space.

Colours
The solar cells in a solar panel do not completely fill the area of the solar panel; there is a small gap around the end of each solar cell. Every solar panel has back sheet on which the solar cells are fixed and this backsheet can be white or black. A black back sheet looks better as it is closer to the colour of the cells but is slightly more expensive. It also causes the solar panel to get hotter and be less efficient.

The frame of the solar panel can be silver or black. This does not affect the performance of the solar panel but a black frame looks a bit nicer on the roof.

Cell Types
A solar panel is made of solar cells. Each cell is about 125mm, square. The cells can be made by using one of two different materials, monocrystalline or polycrystalline. Polycrystalline is slightly cheaper but is less efficient. Solar PV panels made with monocrystalline cells will generate more energy than one made using polycrystalline cells, but will be more expensive.

Manufacturers
Many Solar PV Panel manufacturers will claim to make top quality panels that will last for 25 years or more. They will all offer a warranty of 10 years or more but it is important to select a manufacturer who you can be confident will still be in business in 10 years to honour that warranty.

With major world brands like Canadian Solar, JA Solar and others, you can be confident they will be around for the long term. Other smaller companies may not survive in the very competitive solar market.

Canadian Solar’s PV panels are particularly well suited to the harsh environment and extreme temperature ranges common in South Africa.

With the potential threat of load shedding, more South Africans are looking into installing alternative power sources and heating in their homes.

Solar power is often considered one of the best alternative power sources. Although the initial installation cost is high, it can save you thousands of rands in the long-term.

Solar PV Panels installed on the roof, pole-mounted, ground-mounted, wall-mounted or installed as part of a shade structure, collect solar energy and convert it into DC electricity which is fed to a MPPT. The MPPT use the DC electricity from the solar panels to charges the batteries.

The batteries is then connected to an inverter, which changes DC (direct current – positive and negative) into 220V AC (alternating current) to power up household appliances.

Calculating the required number of Solar PV Panels

To determine how much solar power is needed, start by looking at how many kilowatt-hours (kWh) of electricity is used in a year.

One kWh is 1,000 watts of power being used in an hour. Therefore, 20 lights with 50-watt bulbs in a home with every light on in the house for one hour would use kWh of electricity. The average household use 897 kWh per month or 11,000 kWh per year.

If a 365kWp solar PV panel is used and an average solar panel production ratio of 1.5, divide 11,000 kWh by 1.5 and then by 365 (panel wattage). That will give the average number of PV panels needed.