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Pretoria Area

PostPosted: Sat Jan 26, 2008 7:46 pm
by genman

I'm not to sure about this but would it make sense to do something like this in Pretoria since there is not really a lot of wind here.


Re: Pretoria Area

PostPosted: Sat Jan 26, 2008 8:12 pm
by windgat
Hi Gerrit. Yes, there is not much wind there. But I know someone who put up a turbine near there, so its possible, You just need a bigger diameter, maybe 4 or 5 metres, which means you need to have space. Are you in suburbia or on a farm?

Local terrain also is very important, so you might have a hill than accelerates the wind, or a line of trees that blocks it. The ideal thing is to measure the wind speed over time at the height you plan to have the generator, then to calculate the diameter needed to get the power you would like to get. A quick alternative is to look for a local airport or flying club which might keep a historical log of wind speeds.

Re: Pretoria Area

PostPosted: Sun Jan 27, 2008 1:57 pm
by genman
Thanks for replying. This is exciting stuff. I'm now building a simple inverter system that will run off 4 deep cycle batteries and a charger. We've lately been hit by a lot of power outages which causes havoc regarding my work situation. I'm a programmer and work from home. This system should keep about 4 PC's running for up to 6-8 hours if my calculations are correct and maybe 2 energy saver lights. What I would like to do in the long run is hook up solar panels and hopefully a wind turbine to keep the batteries charged so that when a power outage strikes so that I can keep on doing my thing. I think it would be the coolest thing to generate your own power from scratch and not rely on the grid but I think I'm too ambitious as solar panels cost an arm and a leg and wind turbines may not be practical in my situation. (see below)

Unfortunately I'm in suburbia and the size of the plot where my house is built on is about 900 m2 - Do you think it's possible/practical to put up such a large turbine in such a small space? It will probably need to be at least 9m up in the air as there is a lot of high trees here as well. The safety of something like this is also a concern I would think. If it falls over or a blade breaks then it could cause some damage to the property of surrounding neighbours. Your thoughts on this would be very valuable.

Also would you perhaps know how long it would take the turbine to charge a bank of 4 deep cycle 100ah batteries? I might be able to add a 75 watt solar panel to this as well depending on the finances. (they are extremely expensive)


Re: Pretoria Area

PostPosted: Sun Jan 27, 2008 7:20 pm
Hi genman,
Yes, I think a lot of people share your concerns and wishes for alternative power. I do think you've started with the correct equipment (inverter, batteries and battery charger). Without alternative energy or power source, any such equipment will be counter productive with the current ESKOM situation. What we are doing with such a set-up (and many companies and individuals are guilty, but not without reason!) is to create a WORSE condition by demanding MORE POWER from ESKOM the moment the power returns after a failure! We use more power to charge the batteries than we've used before the crisis exactly because we want to protect our interests (and rightly so, it is not OUR fault that we are in such a mess, ESKOM didn't plan ahead).
Some light in the (dark) tunnel is that apparently a South African patented solar panel will be available soon. This involves modern technology and the panels are developed further in Germany, but will be used here later on. I just hope that it will not follow the same path as SASOL who now charge us the same for petrol as if it was refined in Singapore and shipped here as a finished product; the consumer does not pay less because it is a South African product!
Maybe, just maybe we will get those solar panels at a subsidized price when they appear. This might just be the solution to your requirements.
My ultimate aim, however is to have my own wind genny in the backyard and it is possible here in the Cape because of the wind (except in February/March).

Re: Pretoria Area

PostPosted: Sun Jan 27, 2008 8:24 pm
by windgat
Hi genman. That seems tricky - 9m high. And the rule of thumb is to mount the turbine twice the height of nearby obstructions. Maybe query local building regulations and see what response you get. The more applications for this kind of thing the more chance they have of (eventually?) being accepted.

Four 100Ah batteries - lets say you only use 50% of capacity (to get long life out of the batteries), then that makes 200Ah. If you run at 12V, and get 500W from a small turbine, thats about 40A, which means 5 hours to fully charge (the 50% of used capacity). Double that if you run the batteries flat (a bad idea), or if you get 250W from the turbine.

A 75W panel would deliver about 6A at 12V, which means 32 hours of sunlight to charge the 50% capacity of your battery bank.

Hope that helps (and that my calculations are correct!).

Re: Pretoria Area

PostPosted: Thu Sep 10, 2009 12:35 am
by MontyPython
Hi genman,

i found this website,
scroll down to the bottom of the page for the solar panel things.
these lights seem to use a lot less electricity than what is in the shops these days.

Re: Pretoria Area

PostPosted: Thu Sep 10, 2009 6:35 am
by Greystoke
LED's (Light Emitting Diodes) are the best, certainly since they managed to get pure white lights and increased energy. Efficiency is up to 8x that of an incabdescent light, but . . . . they're still VERY expensive.
I've decided to go for them, but I'll buy them slowly, slowly, one (or two) at the time. :D

Re: Pretoria Area

PostPosted: Wed Dec 09, 2009 11:14 am
Hi All I also stay in the Pretoria Area on the side of a hill and there is also a slight breeze blowing that looks like is might have some potential. I recently acquired a Raylite ' silver calcium, lead calcium battery' with the flowing specs '12v 102Ah' and a ECCO-680 230volt inverter. My grandpa gave the lot to me when he upgraded his emergency power system, I think he used this stuff for about one year during eskom load shedding.

I would like to start playing around with wind power generators as the solar cells are a bit out of my student budget.

my starting question would be; which would be the best option for a generator a cars fan or an alternator?

Re: Pretoria Area

PostPosted: Sat Dec 12, 2009 10:58 am
by windgat
Hi Drake. Nice stuff to get for free!

Neither option you mention is ideal. Search this forum for 'alternator' to see discussions around that.