FAQs About Solar Systems

What is a PV Solar system?

A Photo Voltaic (PV) Solar system consists of : a solar array (panels), a solar panel combiner, a solar regulator, an inverter and a storage battery bank (if the system is not a grid tie system, a grid tie system is normally installed without backup or battery banks). The system can convert solar rays into AC power 230V/ 50Hz.

PV modules produce direct current from sunlight

Inverters convert the direct current into usable grid-suitable alternating current and monitor the system.

You benefit from inexpensive electricity, which makes you more independent.

I want to feed electricity from solar back into the Eskom grid and earn money from it.

Apart from some areas under the Cape Town Municipality and some other exeptions, this is still illegal in South Africa unless you want to start a solar farm with >1MW output.

Why do professional Solar Companies charge for Solar Systems designs?

As with any professional, they are sharing their knowledge, experience and time to provide good advice which will save you time, money and avoid making costly mistakes. It is very easy to make costly mistakes in solar designs and therefore we recommend you use a professional solar design service. In the end it will save you money and you will have a system that works for many years hassle free.

What type of battery must I use in a solar system?

Preferably a deep cycle, high cycle AGM gel battery e.g. Omnipower OPS and the Hoppecke OPzs solar series available from Sinetech. A deep cycle gel battery must be used in this application as it has a much higher cycle life than standard backup batteries and these batteries are therefore normally more expensive than standby batteries. Standard batteries can be use but have a much shorter cycle life.

What is the cost of replacing Eskom with a PV solar system for my house?

This will depend on many factors such as Peak KW and the Kw/h in 24hr period used, size of system, reserve power in days, location, environment, quality of components used, etc. But to give you a realistic but rough indication a small house can cost from R100 000 – R250 000, a medium sized house from R250 000 – R500 000 and a larger house from R500 000 – >R1 million.

Types of Solar Systems

The images below are examples only of some different types of solar systems. Many variations on these systems are available and a solar system like this has to be calculated and designed.

Off-Grid / Standalone PV Solar System
For situations where mains power is not available, or the client wishes to become completely independent of the grid. All power is generated by the solar panels; a battery bank stores excess power for use at night or when the sun is not shining.

Grid-Tie PV Solar System
Very popular in European countries, where residents may feed excess power back into the grid; solar panels provide power during the day, and at night power is drawn from the mains. There is no battery bank or power storage facility in this configuration.

Grid-Tie PV Solar System with backup
Similar to the Grid-Tie PV Solar System but a battery bank for storage of excess power is present; client would not have to use mains if load is not excessive. Due to the fact that a grid-tie inverter must cease operation in the event of a grid failure – ie neither solar nor grid power can be fed in or out while the grid is out of commission – a small, separate backup system is recommended.

Hybrid PV Solar System with backup
With a Hybrid System offers, essential loads are fed by direct solar during the day, whether the grid is active or not. The grid feeds non-essential loads. Excess solar is directed first into the battery bank and then to non-essential loads, to cut down on your electrical bills. In the event of a grid failure at night, essential loads draw power from the battery bank.