DYLAN SCHNETLER | How to choose the right long-term load-shedding solution

Our patience has been severely tested this year with the constant load-shedding. It has become a familiar reality for South Africans, leading to rescheduled plans, increased expenses on food and long hours of sitting in darkness.

Over the past decade, we have all engaged in conversations around the braai, discussing the “perfect” solution to Eskom-proof our homes.

One neighbour suggests buying an inverter, while another claims that her portable power station is sufficient for her needs. As you delve into the depths of Google, searching for your ideal solution, the multitude of options is overwhelming.

Before diving headfirst into purchasing a backup power solution, approach the decision with careful consideration and a long-term perspective, as it is not yet clear when or even if South Africa’s energy problems will ever be solved.

Any money spent on an unsuitable backup solution today will only detract from your ultimate aim of energy independence. Be wary of all the cheap “plug and play” solutions flooding the market. Drop-and-go shippers and dodgy installers often offer no local support, backup parts, nor warranties on their products.

Here are some of the main options to keep the lights on.

Option 1: A UPS

What you can use it for?

If you are looking for a quick and affordable solution to keep your smaller electronic devices like your TV, Wi-Fi router, DStv and a few lights running during load-shedding, a UPS (uninterruptible power supply) is your best bet.

This gadget has rechargeable batteries that store electricity, providing you with a steady source of power when Eskom flips the off switch. You can have an electrician directly link the UPS to your main power board. This way, it will immediately kick in during load-shedding. Alternatively, you can simply plug your desired device directly into the UPS.

Just remember not to overload it, as that might cause it to trip or potentially get damaged. If you purchase a UPS for about R1,000, don’t expect it to handle power-hungry appliances like kettles, air fryers or hairdryers. At this price point, you’ll be able to run essentials like your router and fibre box, while possibly charging your phone.

The drawbacks

A UPS is affordable and easy to set up (unless you want it connected to your mainboard).

However, it comes with limitations. It can only power small appliances, and it may not be feasible to increase the storage capacity to provide a longer backup runtime or enhance the power output for larger devices. The backup runtime depends on factors like the UPS capacity, connected load and battery capacity. Some provide a few minutes of backup, while others can keep things running for hours.

Option 2: A portable power station

A versatile option

Portable power stations have gained popularity as a versatile choice for many households. Originally intended for camping and outdoor adventures, these devices come equipped with built-in batteries that can provide anywhere from 100 watts to over 1,000 watts of power. They are commonly fitted with 220V South African plug points and USB ports, which means they can power a range of devices.

What sets portable power stations apart is their ability to provide extended power supply for hours and provide more electricity than a UPS. Unlike a UPS, which is primarily designed for backup power during outages, a portable power station can be used in various situations, including outdoors. You can also often recharge it using solar panels or conventional power from the grid.

Choosing the correct size

Choosing the right size for a portable power station can be challenging. Typically, the costlier the power station, the greater its battery capacity for storing electricity. The storage capacity is measured in watt-hours (Wh) or kilowatt-hours (kWh). If you turn on a 60W light bulb for 10 hours, it uses about 600Wh of energy.

The size of your portable power station will depend on what devices you wish to power during load-shedding and for how long. Start by identifying the wattage needed for each device, which is usually indicated on the device. If you want to keep more than one device powered for the entire two and a half hours of load-shedding, just add up the wattages of all the devices and multiply it by the number of hours to determine the approximate capacity you will need.

Option 3: A complete backup power system

If you are exhausted from enduring countless nights without power and desire a reliable solution that allows multiple appliances to operate during load-shedding, a complete backup power system is the answer. 

Broadly speaking, there are two options available: a system that includes only an inverter and batteries, or a more comprehensive system that combines an inverter, batteries and solar panels to generate electricity.

What is an inverter?

When your gym buddy told you he had an inverter installed, it means he had an electronic device installed that converts direct current (DC) power into alternating current (AC) power. Inverters take the DC power from a battery, solar panel, or other DC sources and convert it into AC power. AC power is the type of electricity used by most household appliances and electronic devices. Technically, a portable power station and a UPS have this same functionality built in but on a much smaller scale.

Battery only vs solar panels

The DC power source that the inverter converts into AC power usually comes from batteries but can also come directly from a solar panel. With a battery-only system, the batteries are charged when the mains power is on.

If you opt for a battery-only system, you won’t save any money on your electricity bill. This is because after load-shedding, the batteries need to be recharged using a significant amount of Eskom power.

To maximise cost savings, it is highly recommended to install solar panels to generate electricity. By harnessing the power of the sun during daylight hours, you can keep your batteries fully-charged. Once the batteries reach their capacity, you can directly use solar energy to power your home, resulting in significant savings on your electricity costs.

A popular choice for many households is a hybrid system that combines solar power and grid electricity. This set-up ensures a continuous power supply, regardless of cloudy conditions or night-time.

A high-quality inverter offers a range of additional essential functions, including monitoring and optimising the performance of your solar panels.

Inverter capacity

Choosing the right size inverter is a balancing act. Inverters installed as part of a solar panel and battery backup system come in various power output capacities measured in watts. The power output of an inverter determines the maximum amount of electrical load it can handle.

Selecting the right size inverter is crucial to ensure the efficiency and effectiveness of your system. This decision depends on the size of your solar power system and your energy needs.

It’s important to select an inverter that can handle the output of your solar panels without squandering money on excessive capacity. If the inverter is too small, it may struggle to handle the output of your solar panels, leading to decreased performance and efficiency. Conversely, if the inverter is too large, you will pay for unnecessary capacity.

To determine the correct size solar inverter for your system, it is a good idea to consult with a solar installation professional or use an online inverter size calculator to help you determine the best size for your specific energy needs.

Potential scenarios

Investing in a solar-powered backup power solution can feel overwhelming, especially when you are unsure of the cost. However, Synapse Ultra offers a convenient online calculator that can help you determine the cost of a system tailored to your specific needs. Let us consider two examples.

Scenario 1: Dynamic duo

Suppose you live in a household of two people and spend R2,000 per month on electricity. One of you works from home, and you have an air conditioning unit installed in the living room. You use a gas stove and collectively use the washing machine, dishwasher, and tumble dryer 10 times per week. Your house is about 400m² in size, and you have one geyser for hot water. You also have a small 9m² pool.

To ensure a backup power supply of at least two and a half hours during load-shedding, the minimum system requirement would be a 5kW inverter, six solar panels capable of generating 2.76kW peak, and a battery system with a capacity of 4.8kWh. This system would require a one-time payment of R111,000. With this set-up, you will be able to power essential appliances such as your fridge, lights, microwave, television, and even your air fryer during load-shedding.

On the other hand, if you prefer a battery-only solution that meets the same specifications, the cost would be R66,000.

Scenario 2: Thriving tribe

Let us explore a larger household with greater electricity needs as an example. Imagine you are a family of five living in a spacious 600m² home. Your household has two air conditioning units and relies on an electric stove for cooking. Your monthly electricity bill is R5,000, and jointly, you use the dishwasher, washing machine, and dryer around 15 times per week. Unlike the previous example, there is no swimming pool, yet you have two geysers providing hot water.

In this scenario, a basic backup power solution would cost R91,000. However, for increased reliability and an extended backup time of at least four hours, it is recommended to opt for a system consisting of a 5kW inverter, 10 solar panels, and a 10kWh battery. This enhanced system will have a total cost of R161,000. If you choose to exclude the solar panels, the same system would cost R91,000.

These figures show that reducing your reliance on Eskom doesn’t have to be excessively costly, especially considering the various financing options available. The key is to find the ideal solution that aligns with both your needs and budget. Therefore, Synapse Ultra offers pre-engineered kits that are ready to be installed, ensuring a convenient and tailored approach to meet your requirements.

• Dylan Schnetler is commercial head for Synapse Ultra at Rubicon.