How to start planning for a photovoltaic Solar System.

With power supply infrastructure in South Africa becoming less and less reliable as a power source and more expensive yearly, more and more people are now considering solar power as a alternative option for their homes and businesses. This article will point out some pitfalls and some important advice that will help you with your planning.

Step1 : Determine your kw/h needs and realistic expectations.

Everybody have expectations, so its important to understand what your home or business energy requirements per day/week/month and year might be. Make a list of the devices and appliances you have and what their power ratings are. You can use our free Solar Planner Form  spreadsheet to help you plan. Understand what the benefits of solar energy will be and what the disadvantages might be for your requirements.

Step 2: Do a proper PV panel production assessment for at least a few different panels.

There are thousands of panel manufacturers now on the global market. An they are offering many solutions. So finding a reputable panel can be a challenge. Photo Voltaic  Panels varies in size, output rating and efficiency. Some panels also performs better in cloudy conditions , while not costing a lot more initially.  Other panels are smaller but deliver more energy per square meter. Selecting the wrong modules will incur a small loss that will be exaggerated over the lifetime of the product.The net effect will be a bad ROI over the long run. So choosing the right panels could save you a small fortune over a period of 10 to 20 years.Higher quality panels are normally a bit more expensive , but in the long term they yield a better return on your investment.

In short , for panels you normally get what you pay for. In order to determine your ROI on panels a study can be done that use various models and PV production data to calculate the best ROI from the range of panels over time.You also need to consider your roof size, the roofs orientation , inclination, location and topography to calculate the correct roof yield per year.  An proper roof yield assessment will determent the best yield vs cost option for your roof and budget could go a long way in finding that sweet spot. 

Prefer to look for a panel that will match your needs best.

So doing a proper roof assessment for comparison between different modules can achieved more realistic expectations on future savings. Orbic Solar uses statistical data form weather patterns over the last 10 years or longer in our planning and forecasts. Just make sure that the data you use are real and reliable for you area.

Our suggestion is to stick with brands that are reputable and have a proven track record. Also look for a panel that offers more yield than what you pay for and at least a 25 year output warranty.

Step 3: Make a list of all appliances in your home or business that needs to run off-grid

This is very important, as you will have to choose a inverter that will be able to meet the current and voltage requirements of the loads that will be connected on the inverter, also take the time to write down all the appliances current requirements. Putting this in a spreadsheet will help you compare values much easier. We have designed a spreadsheet that is free for you can email us and request a copy , we will gladly share.

Step 4: Determine the Inverter type and size

Once you have a list of all the appliances that you want to run from your inverter, it becomes time to determine the size of your required inverter. Its always a good idea to over rate your inverter capacity as most inverters cant run continuously at the rated specification. The correct way of sizing a inverter is to allow a safety margin of 75% – 150% .For example if the loads that normally run is around 1.5Kw you will probably need a 3 kW to 4 kW inverter.  We have seen many clients buy a 5 Kw inverter and burn it out , because off excessive heat due to running to many high loads on the inverter at once. And and not allowing any safety margin. Remember the rating of the Inverter is not a target but the maximum peak power the inverter can handle for a short period.

If your budget is to tight to upscale the inverter sice, we might be able to provide electrical automation system that will manage the loads, so you dont overload your inverter. Eg while the kettle is on, the stove is off. Or while the washing machine is on the pool pump remains off.

Step 6: Choose a reputable Inverter manufacture

This is not a easy task, as there are thousands of different manufactures and each having many models. For a new client this can be overwhelming.

Inverters designs are very different between manufacturers. Most cheap inverters don’t have proper copper transformers and don’t provide reliable operation and proper protection against high loads and over temperature usage ( more than 25% of the inverters capacity).   The biggest reason for this is the usage of low quality cheap copper and zinc inside the transformers and to further lower the cost many companies use lower grade electronic components inside the electronic circuits.  So the net result is a cheap unit that sell easily but don’t last and work according to the promises delivered. 

You must also make sure the inverter you choose is approved by your local council to be legally used in your local municipality region.  Installing the wrong inverter can be a fire hazard and safety risk that might cost you a lot more than what you budgeted for.

Another important fact that people forget when purchasing a inverter is the quality of the charging circuit and charging algorithm. A cheap inverter , normally sacrifice for a low cost charger that wont charge correctly and also wont protect your batteries properly. This and will shorten the life time of your batteries considerably because of incorrect charging practices.

So if you choose your inverter make sure it will be able to handle the loads you want to run at high temperatures and at a very high efficiency. Also choose a inverter that have a proven track record that have been used for many years in severe conditions.

We have trial and tested many different brands and can provide you with the proper solution the first time.

Step 7: Determine your energy storage requirements

Once you have determined you best Inverter solution, it becomes time to plan for energy storage, if required. For Grid tied systems you might not need energy storage. But for Hybrid and Off-grid solutions you will need storage. Next you will need to calculate what amount of storage you need and at what ratings. This  is a very trick expedition. Batteries performs different based on their chemical composition and temperature, so choosing the incorrect battery will mean, you wont get out what you expect and the battery wont last as long as you planned.

So before buying a battery, you need to calculate what the supply current from the battery need to be during normal conditions and what the maximum current must be during a peak such as when kettle, hairdryer or geyser comes on.  You will also need to calculate how long your loads need to run from the battery during load-shedding. Further more , its important to know that drawing more current from a battery bank than what the optimum is, will shorten the life cycle considerably , so planning all this is an very important part.

Quality and Balance and the right Installers are Key to success.

In the end choosing the better quality product and finding the optimum balance , will optimize your investment and produce the best ROI over the long run. Orbic have achieved this after several years of learning and improving our skills. We are excellent in what we do and will provide you with a proper solution that are tailor-made to your need. We look forward to being of service.

Our services is available in :

  • Cape Town,
  • Hermanus and Overberg,
  • Wellington, Paarl, Stellenboch,
  • Somerset West and Strand,
  • Franschoek.

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