The price of learning by experience

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The price of learning by experience

Postby turning green on Wed May 06, 2009 6:19 am

About a year ago I decided to go "green". I've read a lot about peak oil and the environment and the economy and decided that "it's time".

I bought four 14 watt solar panels for R350 each and a regulator for R180, a total of R1580. I found a supplier of second-hand deep-cycle batteries and bought two 172ah battereies for R450 each. I bought a 2.5kW 12VDC modified sine wave inverter for R2800. I rigged it all up. My panels look quite fancy on the skyline on my rooftop.

Then I proceeded to learn and find out exactly how ignorant I was.

The inverter was a TOTAL disaster and I mean TOTAL and I've subsequently sold it at a firesale price of R1000. What was wrong ??!!! Well one has to do a bit of arithmetic to see where the wheels fell off. The only way to compare the input DC side to the output AC side is to compare the equivalent wattage it would take to perform a given task. The relationship is Voltage (V) X Current in Amps (A) = Work Energy in Watts (W) whether AC or DC.

Let us assume we want to run a fridge which takes 1000 watts for a second or two and then runs at about 300 watt for twenty minutes and shuts off for about twenty minutes and the repeats itself. Ignore the 1000 watts for the moment and concentrate on the 300 watt. OK, on the AC side 300 Watts at 230 V gives us A = W / V or 1.3 = 300 / 230. 1.3 amps sounds OK, no problem, BUT look what happens on the DC side 25 = 300 / 12 !!!!!! 25 amps !!!!!! Nothing in our day to day experience takes that sort of current - your plug rating in your house is only 16 amp max. The only thing that takes that sort of current is the starter motor in your car and that you use for a couple of seconds max and you know what happens when you use more than that - flat battery !!

Good Heavens what would happen if you tried to use that inverter at it's rated maximum of 2500 watts. Do the math 208 = 2500 / 12 or 208 Amps !!!!!!! You need welding wires to handle currents like that and submarine or loader batteries to deliver it. I nearly killed my batteries trying to run my fridge during a four hour "loadshed" - in fact, had I not been monitoring it I would have lost them that day. Within an hour my voltage had dropped to 11 V and my batteries were flat !!!! I sold the bleeding thing - virtually gave it away.

My beautiful solar panels are soooo ineffective. On a very sunny day around noon they will deliver together 52 watt or one-fifth of an amp. At night they do nothing and it takes them a week to top up the batteries if I've run a light or two.

To summarise - my first efforts at going green merely changed my colour. I felt sick.

But subsequently things have picked up and my solar geyser is an enormous success and will even pay for itself. Although I do not expect my wind turbine to pay for itself I think it will give me endless hours of enjoyment and keep me in lights. I'm tackling food supply next but that can wait a month or two.
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Re: The price of learning by experience

Postby turning green on Wed May 06, 2009 6:48 am

Made a miscalculation there - my solar panels together deliver 56 / 12 = 4.67 amp not 1/5 of an amp. Still 56 watts at 230 V gives 56 / 230 = 0.24 amp.

But I've never ever seen the panels deliver much more than 2 amps even on a brilliant sunny day and must conclude that the specifications were optimistic and so their rating should have been 12 X 0.5 = 6 watts instead of 14.

You live and learn.
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Re: The price of learning by experience

Postby aero energy on Sat May 09, 2009 7:21 pm

That was an amazing funny story.

I have just finished my own home-built solar geyser myself.
Building a solar geyser is a good starting point for anyone going green i guess.
1 month of work and lots of learning curves including falling of the roof once.
Also did my maths and calculated i am saving about R40 per month
in electricity thanks to this contraption on my roof. Eskom still unbeatable
i guess :)

Nico
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Re: The price of learning by experience

Postby forum_admin on Sat May 16, 2009 11:42 pm

Reposted for Greystoke:

aero energy wrote:I have just finished my own home-built solar geyser myself.
Building a solar geyser is a good starting point for anyone going green i guess.
1 month of work and lots of learning curves including falling of the roof once.
Also did my maths and calculated i am saving about R40 per month
in electricity thanks to this contraption on my roof. Eskom still unbeatable
i guess

Nico



That's rather a disappointing saving :( .
Just started on a solar panel myself. Busy collecting the parts, but now I put a hold on it. Surely R40/month is just not worth it.
How about a windcharger to support an additional geyser heater in the same tank ?

Comments????????????
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Re: The price of learning by experience

Postby turning green on Sun May 17, 2009 4:40 pm

My solar geyser saves me between R100 and R150 per month.

I bought an Xtream geyser and glass faced, copper tubed solar panel from SolarMax in Cape Town and it all came to R7500. My equipment is commercial state-of-the-art and the only home-built part of the deal was the installation which I did myself.

Using Roman catapult technology I erected the whole thing on treated poles.It was a study in articulation and I "catapulted" the geyser to 4.3 meters high and the panel was jacked up on rails and then swung into place immediately below the geyser. The panel is mounted at 40 degrees slope (for South Africa the recommended slope is between 38 and 45 degrees and it faces absolute true north. I insulated all piping, input and output. It has no interference from trees, buildings etc and the only interference between the panel and the sun are clouds.

I found out quickly that if the panel didn't receive absolute clear sunlight for at least two hours a day (summer or winter and is unaffected by wind or outside temperature) then the supply of hot water is not adequate and the electrical element must be switched on - this has happened three times since December 2008. It means that here in the Southern Cape it works admirably.

A couple of considerations. Most people mount their solar geysers on the roof. Not everyone has a true north facing aspect and not everyone can ensure the required slope. Not everyone can erect the geyser immediately above the panel. Not everyone has adequate insulation. Incidentally I chose the geyser that does not have a heat exchanger so the water that passes through the panel is the water that gets stored in geyser and gets used domestically - I'm exposed to freezing but I wanted maximum efficiency.

I wanted the system to work and it does. It may even pay for itself - it's already saving me money. I regard it as one of my most successful ventures.
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Re: The price of learning by experience

Postby turning green on Sun May 17, 2009 4:54 pm

This picture is abit outdated as it does not show the piping and insulation but the idea is there.
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Re: The price of learning by experience

Postby windgat on Sun May 17, 2009 6:39 pm

Wow. It would be great to see a diagram to understand what 'Roman Catapult technology' is!
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Re: The price of learning by experience

Postby turning green on Mon May 18, 2009 5:28 am

I assembled the geyser on the ground and then swung it up to it's final position.
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Re: The price of learning by experience

Postby turning green on Mon May 18, 2009 5:46 am

Jacking up the panel on the "rails" that were hinged to swing the panel into position.
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Re: The price of learning by experience

Postby turning green on Mon May 18, 2009 5:48 am

Panel ready to swing into final position.
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Re: The price of learning by experience

Postby Greystoke on Mon May 18, 2009 7:03 am

Now that's a bit better, and it looks impressive. :D .
Let's take an average saving of R125/month, that means a pay-back time of 60 months (ie: 5 years).

Are you getting a subsidy from ESKOM? (or Google: "Eskom subsidy")
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Cor
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Re: The price of learning by experience

Postby turning green on Mon May 18, 2009 7:32 am

Short answer ------ NO !!!

Longer answer. I got the forms from Eskom and my local municipality. They require documented proof that the equipment was bought from one of their approved suppliers (there I could comply) but then it MUST be installed by one of their approved installers (there I refuse to comply). I did it all myself and I wouldn't want it any other way.

I love inventing schemes and making diagrams and drawings and the finally making it a reality - it's who I am.

It's finally also the price I have to pay. Sometimes the price is high but this one wasn't - this one was pure pleasure and works like a dream.
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Re: The price of learning by experience

Postby Greystoke on Mon May 18, 2009 9:02 am

I understand, but a few grand is still not to be sneezed at.

I used to do ALL my electrical work. I've got a Msc in Electrical Engineering, but I don't have a Wiremen's license, even though I was a member of the Wiring Code team.
However . . . for a small fee one of my company's wiremen came to inspect my work, and signed the job off.

Can you not do something similar :?:
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Cor
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Re: The price of learning by experience

Postby turning green on Mon May 18, 2009 1:50 pm

I suppose so but .....

my brother had a solar geyser installed at the same time as I did but he went the approved installer route, then applied to the municipality and after their inspection and OK he applied to Eskom. He might have been paid by now and I'll ask him for interest's sake.

Still the inspection revealed that he did not have an isolator switch within reach of the electrical box on the geyser. ie the geyser must be able to be isolated by the technician while working on the geyser. He called the approved installer and it was remedied asap.

Just there mine failed as well and I have not yet installed such an isolator switch. I will put one in but right now I'm busy with my wind turbine and IOW I'm not ready - Sorry !!!!!

I know I'm not perfect but I'm so close it's scary !!!!! :oops:
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Re: The price of learning by experience

Postby Greystoke on Mon May 18, 2009 2:30 pm

WEll - for what its worth - I'll give you a certificate (and a star :!: ). You've done a wonderful job, and you can come and install mine any time. Image
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Re: The price of learning by experience

Postby turning green on Tue May 19, 2009 8:23 pm

The Solar Geyser 19th May 2009 - my camera is one day ahead.
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Re: The price of learning by experience

Postby turning green on Fri May 22, 2009 8:17 am

The Art of Struggling.

I had a friend once called Henk and we parted ways and now I haven't the foggiest idea where he is and he might very well be in the happy hunting grounds doing his thing but two things continually remind me that he touched my life.

The first is the Appy. I had some of the worst ceiling damage in Kempton Park due to HEAVY hail, not big hail just too much of it, and I was struggling trying to replace the ceilings by myself. Well he came there and said "You need an Appy !" to which I replied "I don't want to employ or hire people." and in turn he said "Obviously you don't know what an Appy is.".

Is it a person or a thing ?? It's the latter. He loaned me his with the condition that I promise to build my own. I promised and I did. By the way I replaced all the ceilings in my house on my own using that Appy and I've never been without my Appy since.

What is an Appy ?? I'll post a photo of my Appy after this post. It's dead simple - A 1.6 meter of 25mm sq tube with a simple foot and a 1.7 meter of 20mm sq tube that fits inside the 25mm tube. In the 25mm tube is a hole with a nut welded round it and a butterfly bolt to fit the nut. In other words they can be locked in position. A piece of 25mm flat is welded across the top of the 20mm tube with two little uprights 40mm apart forming a U. That's it !!! I've built wooden frames with the universal 114 x 38mm raftering wood and slotted one edge into the U. The frame is lifted into position for whatever job and locked - the Appy stands tirelessly there and holds up whatever - obediently and diligently. I've never looked back. I don't think it took me longer than two hours to make and it's lasted me much more than twenty years !!!

The second is a measuring table. If you can't grip a job then you cannot work or weld it. He had a design there that was built with 60mm angle iron. 10 pieces of 60mm angle 80 cm long and 4 pieces of 60mm angle 50 cm long are cut accurately (I had mine done by the steel merchant that had an accurate cutoff machine. From the photo you can see that 3 sets of two 80 cm pieces are welded back to back and then placed between two 50mm pieces with approx two 7 cmm gaps. ie the table top is 92 cm x 50 cm. One side of each of the two 50 cm pieces is cut off (quite difficult or just buy two 50 cm 60 mm flat bars) and extend the two ends downward. Weld the four legs on splayed at an angle of 7.5 degrees from vertical - The height of the table 85 cm. The feet are trimmed to be level on the floor. The whole thing took me about a day to make and I made two identical ones. Sadly I gave one away when I moved to the Cape and I've had many times to regret that since - No doubt I'll build another one day. I have about twenty clamps of different sizes and there's very few jobs I've not been able to work.

I'll post the picture later - my camera's battery went flat after the Appy.

If you have to struggle (like me) then don't forget to make these two items - preferably two of the latter because it becomes dangerous to part material not properly clamped at the same height.

I wonder whatever became of him - maybe I should put a bit of effort into finding out ??!!
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Re: The price of learning by experience

Postby turning green on Fri May 22, 2009 8:20 am

My Appy. Still patient and obedient after twenty years !!
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Re: The price of learning by experience

Postby turning green on Fri May 22, 2009 11:33 am

The measuring table stands outside waiting for me to use it.
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Re: The price of learning by experience

Postby turning green on Fri May 22, 2009 11:43 am

I turned the table onto it's one end to show how it all fits together. Notice all the edges that can be clamped on - all round and the four inner edges. I'd be lost without it and I sorely miss it's identical twin.
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Re: The price of learning by experience

Postby turning green on Wed Jun 03, 2009 5:35 am

A Strength - A Weakness

I compulsively overdo things - I've come to live with it but it does make life a bit of a roller-coaster ride.

So I've developed some simple (perhaps horrendous) philosophies. Like "If it's not worth overdoing then it's probably not worth doing.". Try living with that one.

How do you like "I can handle boring and bland.". That's led to some weird results.

"I wonder if I could do that ??". Some almost unbelievable situations lie behind that one.

"I eat to live not live to eat.". This one is beyond incredible.

Other than that I'm dead normal. A more simple soul you'll never meet. Sometimes even I like me.

So I over-design so sue me. A lot of the stuff I've built will outlast me, my children and my grandchildren and their children - you get the drift ?? Some of the stuff collapsed under their own weight - tough lessons !! I've come to respect heights the hard way - I've fallen off a roof and a ladder and down a loong staircase. I've had accidents on bicycles, motorbikes and cars. Now I'm a safety freak - see !! I overdo things. I think I'm an expert at doing things the wrong way - maybe champion level, maybe world champion ?! Just there when I think I've outclassed everybody then I meet someone who's done it better, cheaper, more often and they beat me even at being stupid and persistent and ridiculous. "You never win !!" (that one's consoled me through many drubbings and failures).

"Life's tough !" (my favourite) and "Old age is not for sissies" my newly aquired status.

I'll never forget the roof episode. It was during and after the "great hailstorm" in Kempton Park. The "great hailstorm" is defined as the one that affected my life the most because actually Kempton Park is Hailstorm Mecca. Man, we had between 30 and 60 cm of small hail that day and my roof was relatively flat (7 degree slope) and the storm had a strange timeline - it hailed for about twenty minutes and then rained for about ten minutes then stopped for about two hours and did it all over again. During that two hour hiatus is when it happened - my ceilings were already ruined and beyond saving but my whole roof was sagging !!!!!! We could see that the storm was not past (nothing is as dark and ominous as hailstorm weather). So me and my son-in-law got onto the roof with brooms and tried to sweep the hail off the roof.

Nothing in this life is as slippery as lots of wet hail - NOTHING !!!!!! It's a testimony to our persistence and fear that we accomplished what we did because had we not then I would very possibly have died that day. We got so much of the hail off that it was lying more than a meter deep below the shattered gutter. The predictable happened (in hindsight, of course) and as I stepped backwards I must have stepped on the perfect pile of white wet ball bearings and I sailed on my backside at lightning speed - Wheeee !! Hey Geronimooooo !!! and I was off the roof with my broom and onto the pile of hail. Totally uninjured !!! (except for my pride) and I heard "Dad ! Dad ! Where are you ??" - it had happened so quickly and silently that he never saw what had happened. "Here on the ground and I arrived by airmail !!!!".

Needless to say our efforts stopped just there and we accepted whatever was going to happen - we'd deal with the consequences and we did. :shock: and :oops:
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Re: The price of learning by experience

Postby Greystoke on Wed Jun 03, 2009 6:03 am

You certainly know how to make a point and tell a story. :D :D :D
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Re: The price of learning by experience

Postby aero energy on Thu Jun 04, 2009 2:08 pm

Hello all,
For the ones who are interested I’m going to share my experiences with you. My solar geyser is unconventional but does the job.
The roof is used to heat the water which is transported by rubber hose. The roof temperature goes up to about 60C in the summer and about 50C in winter.
Roof.jpg

The water is being pumped into a normal geyser
Geyser.jpg

To pump the water around a automotive fuel pump is being used
Fuel pump.jpg
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Re: The price of learning by experience

Postby aero energy on Thu Jun 04, 2009 2:11 pm

To drive the fuel pump a standard battery is used which is charged by an old solar panel. But its probably a lot easier and more cost effective to use a small 12V charger.
battery + solar panel.jpg

To switch the pump on and off a standard geyser thermostat is used in combination with a relay. When the roof is hot enough the pump switches itself on in the morning. And off in the evening.
Thermostat.jpg

The whole system does not yet provide all the hot water needed to shower. So currently every morning a timer is still needed to switch on eskom power for 1.5 hour to bring the water up to a decent shower temperature. So there is some room for improvement.

So far my contribution to a better world. Any comment is welcome.
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Re: The price of learning by experience

Postby windgat on Thu Jun 04, 2009 2:44 pm

Looks great! :clap:

Do you know the geyser element wattage? Could then esitmate the power used/saved.

An hour an a half seems like a long time. are you sure that long is needed? Would be great if you could monitor and record the actual water temperature!
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