Our solar - photovoltaic panels and an electric car in Cape Town
by Diana Studer
- gardening for biodiversity
in Cape Town, South Africa
When I was a newly qualified librarian working at the Engineering and Science Library at the University of Cape Town, I read New Scientist. Dreaming of one day, when cars would be powered not by polluting petrol or sooty diesel but ... by electricity! The Ungardener drove trucks, then Swiss and South African tourist coaches as a tour guide. Our family car was two (successive) Land Rovers. Between us we have left a large dirty diesel environmental footprint.
South Africa's grid power is mostly from dirty coal. Cape Town generates cleaner pumped storage hydroelectricity at Steenbras, which saves us from one level of Eskom's loadshedding. They are sweating blood to catch up on the neglected maintenance from years of corruption.
|Solar electric (second sticker attempt)|
Could we get an electric car? Realise a long held dream?! In November 2017 we did! On the road and rail trip to Kruger I saw the polluting power stations and we came home thinking about solar power for our home. Our minds sharply focused by - we NEED electricity to charge our car amongst unpredictable loadshedding.
|North facing roof ready and waiting|
By January we had saved to install eight photovoltaic panels on the north facing roof with a single solar battery. (This is NOT a sponsored post, we paid in full for product and installation)
|First photovoltaic panel installed in January|
Our system was installed by Solarelectric conveniently in neighbouring Noordhoek.
|First solar battery in January|
We began a long learning curve. Feeding OCD control freaks. The system defaults to charge the solar batteries first. We have adjusted the timer for the geyser, 12 to 1 and 4 to 5. The car gets as and when. Also tweaked the default to 48% so the solar battery carries us thru loadshedding.
|Our first set of photovoltaic panels in January|
The amber line is grid power. Our prepaid electricity meter for municipal grid power has a default that draws about a KWH daily, with extra little spikes when the geyser or the kettle pulls too much in the moment. Sometimes tripping the whole system, which sulks for 10 to 15 minutes before cooperating again.
The green line is the solar battery, climbing with the sun, then settling at a tabletop if the panels can support our load.
The purple is the load. Spiking to a tabletop when the geyser element is timed to click in as winter support for our solar geyser. On a sunny day, geyser and car battery double the height of that table. DON'T put the kettle on, unless you have checked the system can support the third power hog.
The turquoise line is photovoltaic panels tracking the sun, dipping when a cloud drifts past, soaring as the sun blazes thru. As I write, it is gloomy and wet out there with a winter storm raging.
|Car charged 100% solar on 1 February|
That kettle! We added four more panels to accompany the solar geyser on the roof facing afternoon sun, with a second battery. Now if the sun, panels, and solar batteries cooperate we can sustain the power we need. I can't compare as I did with monthly water usage in 2018 (we are still using about 80 litres each daily) since he used to go to Constantia Village etc for free charging.
|Second set of photovoltaic panels in March|
|Second solar battery in March|
Mid-winter on one of those beautiful blue sky sunny Cape days and the photovoltaic panels perfectly track the arc of the sun across the sky.
|Sunny mid-winter 18 July|
Third time lucky for the new Powered by the Sun sticker on our car.
|Close the circle. Powered By the SUN!|
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Pictures by Diana and Jürg Studer
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