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Helderberg Solar Energy - Renewable Energy Solutions

Helderberg Solar Energy is a Renewable Energy Company that specializes in lowering the cost of energy and the impact on the environment by using the latest innovations in green technology.

Our product range currently offers Solar PV (Photovoltaic) and Backup Systems, Low Energy (LED) Lighting, Solar Geysers, Heat Pumps and Pool Heating.

Solar water heating systems is not a new concept although it only started to take of in South Africa in recent years. It has been in use for more than a century. This ad for a phermosiphon water heating system was placed in 1902.

Helderberg Solar Energy cover the following areas: Gordon’s Bay, Strand, Somerset West, Grabouw, Rooi-Els, Pringle Bay, Betty’s Bay, Kleinmond, Hermanus and up to Pearly Beach. Inland we cover Stellenbosch, Paarl up to Wellington.

Helderberg Solar Energy has been involved in the design and installation of small and big projects. We pride ourselves in our technical expertise and continuous support.

Solar PV Systems

PV Panels

Solar power has never been so affordable with record-low prices on solar equipment. In fact, it is now possible to get a top-quality solar system to pay for itself within 5-8 years, saving households tremendously on utility costs over the life of the system.

What size solar system will best fit your home or business?

Sizing a Solar System

A solar system will output around 4 times its size as a daily average. A 5kW system will output around 20 kWh a day, which is enough for most households to handle the average load during sunny days.

As solar power prices continue to fall and battery storage becomes a realistic option for most households, it is now feasible to size solar systems to match 24-hour PV system usage. Alternatively, to provide at least 3-4 hours battery backup during load shedding with South Africa’s Escom dilemma.

The average size solar systems installed now is 5kW-10kW, or to basically fill the roof with panels where roof space is a limitation.

The main reasons for this are:

Good quality solar systems are significantly cheaper than they were previously.

Property prices are increasing at such a rate that it is becoming a no-brainer to use some equity to replace your power bills for the coming decades and add value to your home

Lithium Ion Batteries have changed the market. Whether you buy one now or in the future it is advisable to get your solar system installed with the presumption that you will store excess solar power as backup in a battery. This means sizing a solar system based on your electricity usage and backup needs.

How Many Solar Panels is needed

Once the average solar power needed on an average day is determined, how many panels will be needed to generate that amount of power can be worked out. Most solar panels are now rated at around 350W per panel, whilst highly efficient panels are now rated at 420W-450W.

High-efficiency modules are a more expensive per panel, however, because you need fewer panels for the same output the cost per Watt is the same.

As an example, if you decide to go with a 5kW solar system for your home, you could then choose to install 14 x 350W panels or 12 x 420W panels.

A lot of misinformation exists when it comes to sizing a PV system and this is not helped by salesmen trying to up-sell customers to large solar systems that they do not need.

When to use solar power?

Solar power only works during the day. Without battery storage, solar power needs to be used as it is generated. The main benefit of solar PV is to directly reduce your power bill by using it as it is generated.

To find out how much power is used during the day, simply take meter readings in the morning and again in the evening. Subtract the two readings from each other and that will give the daily usage. These readings should be taken over a 7-day period to get a good idea of the average daily usage.

The base load

Every house has a baseload. This will typically include a fridge, freezer, lights, TV, Computers and perhaps some appliances like a kettle or microwave oven.

Additional usage

On top of the baseload, it is possible to use some appliances only during the day. Determine how much power can be used during the day without too much hassle?

The biggest users of power in a typical home include:

  • Pool pumps
  • Spa
  • Air conditioning
  • Heating
  • Hair Dryer
  • Dishwasher
  • Washing machine

Generally, do not worry too much about lights (except halogen floodlights) when considering solar power. They use very little power, especially LED lighting and are typically on at night.

Keep an eye on the future. Victron’s free online VRM portal gathers data, which is very useful to monitor the PV system’s performance. This will help to make an informative decision to upgrade the system if necessary.

The output of a solar system depends on which way the roof is orientated and the angle. A 5kW system almost never gets close to 5kWp of output at any one time due to the angle and the orientation of the panels. This could be improved with sun tracking, however, the cost of installing and maintaining an array that follows the sun does not pay for the increase you will get in output. It is much cheaper to just get a few extra panels.

Look at google maps (or get out a compass) to see what roof sections you can install solar panels on. Anything north of west or east is usable.

Panels facing east will output more power in the morning and panels facing west will output power in the afternoon. Compared to North, panels facing east or west will not output quite as much over the course of a year, however, losses are not that great.

In most cases, it can be a good idea to have two PV arrays giving you two smaller peaks of output. This makes it easier to use most of the solar power most of the time, and this is how you can maximize the benefit of your system and hence reduce your return on investment.


According to Renewable Energy World, shading of as little as 9% of a solar system connected to a central inverter, can lead to a system-wide decline in power output with as much as 54%.

Micro inverters can significantly increase output. With a string inverter, the system will be outputting almost no power if parts of the panels are in shade.

It is important to state that bypass diodes are designed to help stop hot spots on panels from bird droppings and the like. They do not work in the same way as micro inverters and will not help maximize output in shaded conditions like micro inverters do.

We hope this information helps you cut through the sales talk.

Solar Water Heating

Solar water heating systems is not a new concept although it only started to take of in South Africa in recent years. It has been in use for more than a century. This ad for a phermosiphon water heating system was placed in 1902.

Solar Water Heating System 1902