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)
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
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
First photovoltaic panel installed in January

 

Our system was installed by Solarelectric conveniently in neighbouring Noordhoek.

 

First solar battery in January
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
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
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 set of photovoltaic panels in March

 

Second solar battery 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
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!
Close the circle. Powered By the SUN!

 

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Pictures by Diana and Jürg Studer

of Elephant's Eye on False Bay

 

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Comments

  1. An impressive way to charge your car. Solar power. Truly green power. We are looking into an electric car at the moment. Reading your post it’s time we got a move on! B x

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  2. Well done! Hopefully one day we will follow your lead.

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  3. Good going! I'm assuming your car is fully electric and not a gas / electric hybrid? Though the ethical payback is immediate, about how long would the economic payback be, comparing the solar and battery vs. electricity costs?

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    Replies
    1. Absolutely fully electric.

      South Africa charges a high tax on imported electric cars. We also have no subsidy against the solar panels. For us it was an ethical, not an economic, choice.

      Delete
  4. Kudos to you and your husband, Diana! My husband converted a gas-powered car to electric and drove it for close to 2 decades when we lived in the "flatlands." When we moved, it couldn't handle our current hilly area as well (it was an old car even at the time he converted it) so he passed it along to our nephew, who ultimately donated it to high school machine shop when he left for college. I'm hoping my next car will be electric and I'd also like to add solar panels to our roof - my husband's not all on board on the latter yet due to difficulties connecting to the power grid here.

    ReplyDelete
    Replies
    1. We have a grid-tied system. But we don't feed into the grid, as that requires a costly permit - not worth it for our small system.

      Delete
  5. Awesome setup. We have done a similar exercise but have an additional boost from a wind generator. Cold wet and cloudy days are usually windy so it has worked out well for us. Over time we have switched to gas for showers, hot water in the kitchen and the kettle. During the water crisis we took our house off council water and switched to tanks only and initially load-shedding meant no water as the pump was Eskom supplied. We had added a few panels and two extra batteries and now no longer require Eskom for water. this also powers the security cameras, wifi and several internal and external lights. Load-shedding is now no longer an issue. The system is not grid tied and does not cover everything in the house but it saves electricity costs and the reduced impact and independence is a nice reward. An Electric car is very high on our bucket list.

    ReplyDelete
    Replies
    1. Luckily the pump that was recommended when we converted our rain tanks to supply the house (when we have capacity) uses minimal electricity - but that pump was part of what decided our solar setup.

      We make a point of using one kilolitre of municipal water each month, as we depend on CoCT infrastructure to process our sewage.

      I prefer a conservative (living green) lifestyle to using gas. But we do have a small gas stove if we MUST cook with loadshedding and empty batteries under grey skies.

      Delete
  6. Really interesting post! Enjoyed the graphs. The arch that tracks the sun is very cool! Love the sticker on your car, too.

    An electric car was a dream from childhood and it was one of the childhood dreams that came finally true. We love our EVs. I don't miss going out all that much since the shut-down for Covid-19, but have missed driving my EV. Do not miss gasoline one bit.

    I would love to add more panels so we can cut out the nat-gas water heater and go 100% electric, but our roof is not a long stretch like yours. It in many sections (silly architects) that make adding more panels difficult. Hope to find a solution yet.

    ReplyDelete
    Replies
    1. Dreams can come true!

      What happened to the solar roof tiles idea? Was it Tesla?

      Delete
  7. Well done! How are you? A friend told me that Cape Town is still in lock-down and that no alcohol or cigarettes are sold. I hope that is not true.
    Amalia
    xo

    ReplyDelete
    Replies
    1. We have moved from level 3 to 2. Cigarettes and alcohol are again for sale - neither of which do I buy. Sadly with alcohol we are back to traffic accidents and hospitals dealing with alcohol related trauma.

      Happy that the restrictions on seeing family are easing. Still being careful. We have had a first restaurant meal, much enjoyed once we adjusted to masks and sanitiser.

      Delete
  8. Oh, good for you! Solar power and an electric car have long been on my wish list, too. I've been compromising by driving a hybrid car for the past 17 years, and I think I will get either a fully electric car or a plug-in hybrid for my next car. I had just about given up on solar because of all the shade from trees where I live in the woods. But a community solar farm is coming to my area, and I can buy shares that will offset my electricity usage. Yeah!

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    Replies
    1. What good news, sounds like a perfect compromise!

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  9. A big big WOW dear Diana, that's an amazing thing to do. One of the best for our climite and mother nature .. and at least for us. Congratulations and standing ovations for this step. The car looks super good with it's yellow and black. Like a little wasp or tropic butterfly. I sold my car two years ago and use the bike for the city.
    Thank you for your lovely words, all my best with the car, all my best for your health and happy spring
    Elisabeth

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    Replies
    1. If we lived in London or Zurich I would revel in efficient public transport. Sadly Cape Town's public transport is more Third than First World. One day!

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  10. Very interesting to read about your experiences with the electric car and solar panels. It must have been frustrating with the electric tripping! We have the electric car and the solar panels but without the battery. It is amazing how many extra mileage we get out of the car in the summer months, do you find it varies for you through different seasons? I love the message on the back on the car, that's a great way of spreading the message. Sarah x

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    1. I can believe you do better in summer. We only noticed the winter cold effect when we journeyed north to Kruger. We had one VERY cold night there, and plugged in all night the battery didn't charge fully. Grateful that it perked up during the day as the temperature rose.

      Delete

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