Soaking up the sun is rewarding,
Installs a solar power system but discovers that getting everyone in the house to use less
When the stroppy septuagenarian accuses you of trying to kill her after she’s endured the ignominy of two lukewarm showers in the middle of winter in Joburg, the correct replies are not “if that was my intention I’m sure I could find a quicker way to kill you, mom,” or “have you heard of this crazy Finn, Wim Hof?”
Going solar isn’t all it’s cracked up to be, particularly if the people living with you don’t understand the experimental nature of installing a grid-tied solar power system.
Do the research
When I started researching solar power systems, I found the whole process daunting. We’re being asked to spend as much money as we would on a car, yet there is little in the way of regulatory authorities or a sunny ombudsperson ensuring we’re not all buying the equivalent of skorokoros with a Ferrari badge glued onto the bonnet.
So I’m going to explain what I did and why, in the hope that it will help you make a more informed decision about residential solar power systems. But I’m not an expert in this field and I therefore encourage you to spend several hours doing your own research, so you don’t end up being accused of trying to kill your mother because you forgot to put the geyser timer on.
Energy audit
We have a prepaid electricity system, so it was easy for me to calculate a daily average usage, and ours was about 60kWh per day. Installing a solar power system just to get you through rolling blackouts/load shedding isn’t going to work if you don’t know how much electricity you’re using every day.
While doing your own energy audit, you will soon realise that any appliance with a heating element is an energy-sapping fiend. For example, if you have a 5kW inverter and you use a toaster (about 1kW), an electric kettle (1.6kW) and a microwave oven (1.4kW) while the dishwasher (2kW) is on during a blackout, you’ve overloaded the inverter.
What’s worse is that some inverters, such as certain models of Growatt, have warranties that are voided in the event of the inverter being overloaded.
So if you don’t take the time to understand how much electricity your appliances use, you might overload your inverter and void the warranty a few days after it’s installed.
Get at least three quotes
I sourced quotes from three companies, asking each installer the same 15 questions.
Don’t blindly trust what the solar power installers are telling you, because suddenly everyone giving you a quote will have been in the solar business since Ra was a wee lad.
Compare their answers to your own research and speak to people who already have solar power systems. You’re going to be spending anything from R100,000 to R500,000, so take your time to choose the right installer who gives you the best advice for your situation.
One of our potential installers made the lofty claim that with a 3kW inverter and a 3kW battery he would be saving us more than 70% of our current energy usage. That sounded too good to be true – and it was, because he didn’t tell me that his idea of saving us 70% meant that our geysers, dishwasher and washing machine wouldn’t be attached to the inverter.
Many people are choosing to exclude geysers from their solar power systems, which means the geysers will only ever draw power from Eskom/the power grid, but there are pros and cons to this choice. If you do this you will ensure the geyser never drains your battery, but how will you heat water in the event of an extended power outage?
We chose to install geyser timers with a smartphone app so that we could control the geysers, but there was that one morning when grid power hadn’t come back on as scheduled after load shedding and the geyser nearly drained the battery.
DO NOt GO Off-GrID
We’re all furious about how State Capture has decimated Eskom, but going for an offgrid setup isn’t feasible. There are instances when the power grid comes in handy, such as a week of rainy weather when your solar panels won’t generate more than 30% of their normal output.
And if something goes wrong with any components in your system and the inverter is not supplying power to your home, you’ll be glad that Eskom is still an option. A gridtied/hybrid setup is the way to go for most residential solar power needs.
Turning sunshine into money
Solar panels are heavy. Ours are 545W monocrystalline panels (polycrystalline ones don’t work efficiently when it’s cloudy), and each one weighs about 40kg. We currently have 10, but ours is an old house, so we had to start this whole process by replacing some of the beams in the roof to ensure the weight of the panels wouldn’t be a problem.
I spent a fair deal of time monitoring which parts of the roof had the most sun throughout the day, and I checked that the sunlight wasn’t being obstructed by any trees. During this process, I noticed that one of our neighbours had installed 15 super-duper glass solar panels. They’re beautiful, all-black and gleaming happily in the sun on a Tuscan-styled roof.
Once I got over my bout of panel envy, I asked our street WhatsApp group if they could recommend any solar power installers, and we ultimately went with a company that one of my neighbours recommended.
What I appreciated about Crown Technologies, other than the fact that they answered the never-ending list of questions I had, was that they wanted to decrease our overall electricity usage. They also had a finance option, which we didn’t use because we chose to extend our bond, and their main aim was for me to understand how to utilise the energy generated by the panels to “turn sunshine into money”.
What we did
We had two 200-litre geysers in the main house and another one in the cottage. We disconnected one of the geysers in the house and immediately saved 20kWh per day.
The two remaining geysers had 4kW elements, which we replaced with 2kW elements, and we installed timers to ensure the geysers aren’t on 24/7.
When you install a solar power system you’ll be able to put certain appliances on the essential list (these appliances will draw power from the inverter) and others, like the electric stove, on the non-essential list (these appliances will only ever be powered by the grid and not by the inverter at all).
We chose to put everything except the electric stove on the essential list, including the pool pump. We did this so that we could run energy-intensive appliances (the washing machine, dishwasher, pool pump and geysers) during the sunny hours from 10am to 3pm to ensure that we’re making the most of our solar panels.
We started with seven panels, a 5kW Greenrich lithium battery (always choose lithium over lead or gel batteries) and a 5kW Sunsynk inverter. I chose the Sunsynk inverter because we can install up to 13 panels on this inverter and if we want to expand the system, we’ll be able to install another Sunsynk inverter with additional panels that can be linked to the current inverter so that it all operates as one system.
After a few weeks we added three more panels and after four-hour blackouts, we added another 5kW battery because the current battery only just made it through the four hours.
During power cuts at night, we don’t use any big appliances and the geysers are off. The battery powers essentials such as the fridges, freezers, exterior LED lights, the WiFi router, laptops and the electric fence.