Planning your own Solar Power System

johnjm said:
Do your sums dude, it will take 15 years to make back the investment.
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10 x 300W PV Panels: R20K
4 x 200Ah 12V Batteries: R14K
1 x 3.5KW Hybrid Inverter: R19k

The Hybrid inverter allows me to offload pretty much 100% of my day time energy, the batteries are there only to serve as backup during load shedding.

Total cost: 53K. Let's add some butter for fittings, cabling, and all the other small things, and call it R80K...

Avg monthly electricity bill is R5K. I'm looking at about 32 months ROI (2 to 3 years). Let's be conservative, and call it 5 to 10 years.

And price of electricity is still going up, whilst solar is continuously coming down. A few years ago yes, you looked at a ROI of 15+ years. It's definitely not the case today anymore.

EDIT: And with a small additional expense of increasing the battery bank slightly, I'm sure I would be able to run the majority of my night time energy usage from batteries too...
 
R5k per month? That's probably 4400kwh per month? Is it a hotel?
 
Even if it is R5k per month, and even if the small 3.5kw inverter could handle your average loaf which is unlikely at that monthly cost, its an 8 year return.

Pretty useless then.

If load shedding extends to 8 hour periods then yes, its worth it, and will further separate the haves from the have-nots. Then you will be laughing at us.. Although doubtful.

Then again you never know...
 
savage said:
10 x 300W PV Panels: R20K
4 x 200Ah 12V Batteries: R14K
1 x 3.5KW Hybrid Inverter: R19k

The Hybrid inverter allows me to offload pretty much 100% of my day time energy, the batteries are there only to serve as backup during load shedding.

Total cost: 53K. Let's add some butter for fittings, cabling, and all the other small things, and call it R80K...

Avg monthly electricity bill is R5K. I'm looking at about 32 months ROI (2 to 3 years). Let's be conservative, and call it 5 to 10 years.

And price of electricity is still going up, whilst solar is continuously coming down. A few years ago yes, you looked at a ROI of 15+ years. It's definitely not the case today anymore.

EDIT: And with a small additional expense of increasing the battery bank slightly, I'm sure I would be able to run the majority of my night time energy usage from batteries too...
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Where were you able to obtain 300w panels at R2000 a pop? Hell if I can find it at that price??

For some people it merely goes towards future proofing your expenses, i.e. electricity tariffs. Bugger the repayment period which is a highly subjective calculation in principle..
 
edmundp said:
Where were you able to obtain 300w panels at R2000 a pop? Hell if I can find it at that price??

For some people it merely goes towards future proofing your expenses, i.e. electricity tariffs. Bugger the repayment period which is a highly subjective calculation in principle..
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Whoops - sorry, R30K :) It does however depend on where and how you get them. R6.80 / R7.00 per Watt is on the lower side of the scale.

And yes, I do agree with you. Some are also just after the reliability too (i.e. having power).
 
savage said:
Whoops - sorry, R30K :) It does however depend on where and how you get them. R6.80 / R7.00 per Watt is on the lower side of the scale.

And yes, I do agree with you. Some are also just after the reliability too (i.e. having power).
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Indeed. And to avoid the noise of a generator. Drives me nuts. Want to sell mine eventually. Not speaking of the running costs.

Any ideas to where I can get the 'lower side of the scale?' Everything I get below R10/W is just simply chinese junk...
 
edmundp said:
Where were you able to obtain 300w panels at R2000 a pop? Hell if I can find it at that price??

For some people it merely goes towards future proofing your expenses, i.e. electricity tariffs. Bugger the repayment period which is a highly subjective calculation in principle..
Click to expand...
Why is the return on investment a subjective calculation?
 
10 x 300W PV Panels: R20K
4 x 200Ah 12V Batteries: R14K
1 x 3.5KW Hybrid Inverter: R19k

Wiring and other bits R5k
-
R60k odd


60,000 / 12 / 5 (5 years = R1000 a month)
3000W of panels should give you close to 15KWhr a day in summer, 4.5KWhr in winter. I'd probably go with more, but thats me.


15KW day (450KW / month ) is around R2 a KW in most municipalities.
At current rates this is already close to a 5 year "payback". Probably 3 year payback at 15% a year Eskom/Muni increases.

How is this not a no-brainer?

(Yes I've excluded winter charges and other things like financing costs, but its fairly clear that solar has reached grid parity pricing already, especially without storage. With storage is a bit of a toss up, but thats not going to be for much longer at current increases)

At the end of 3-5 years your sunk costs are covered by the money you save on not paying the bill, and the panels / inverter will last at least 10 years. Batteries will be hosed, but Lithium is dropping fast, and will be a much more viable option in 5 years, giving much longer lifespans.

Older calculations on that here - http://goingsolar.co.za/2014/12/05/eskom-municipality-vs-solar-pricing-maths/
 
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johnjm said:
Why is the return on investment a subjective calculation?
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Well we for instance work from home and would have lost several days of production if we had to stop working every time load shedding occurs. Not to mention potential savings on insurance claims due to appliances being fried by surges. So it's quite difficult to calculate the true ROI.
 
InifiniSolar 3KW Plus which is a fully programmable, Hybrid inverter is also sub R20K. Brilliant piece of hardware.

I'm actually thinking of putting a nice load shedding special together... 3KW hybrid solar with battery backup for ~4 hours runtime, sub R60K... Hmmm....
 
Naks said:
out of stock everywhere. ComX says the backorder arriving end of May is already sold out, another shipment due mid/end June.
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BonanzaTech does not mention that they are out of stock, but best to query first.
Anyways, the prices of these inverters differ quite a bit between places.
 
I don't think the Axpert mentioned is hybrid though...? Anybody care to chime in?
 
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