Micro inverter to grid

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suPerb0b

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Hi guys
I was told that a micro inverter can easily plug into any plug outlet in your house and supplement Eskom power from the solar panel to your home.
I've done some googling and it appears that it may just work this way, although I haven't seen anyone state it as a fact.

Does anyone here have a solar setup where the micro inverter(s) plug into a wall socket? If this is not the case, how the hell do you connect it to your house?
 
Its not legal per se, even though there are a couple of guys on here who are feeding back into the grid. There's LOTS of red tape around it. Its also extremely dangerous so please don't try this.
 
suPerb0b said:
Hi guys
I was told that a micro inverter can easily plug into any plug outlet in your house and supplement Eskom power from the solar panel to your home.
I've done some googling and it appears that it may just work this way, although I haven't seen anyone state it as a fact.

Does anyone here have a solar setup where the micro inverter(s) plug into a wall socket? If this is not the case, how the hell do you connect it to your house?
Click to expand...

That is a Grid-Tie inverter and yes, you can just plug it into a wall socket. Electrical sockets are rated at 20A, at 230V that gives you 4600W. A small inverter will not harm your wiring. If you are talking about 2KW or up rather wire it directly to your distribution board.

As for legality, you need to have a smart meter that supports feeding back into the grid, otherwise the power you produce will also be counted against you!

Good luck finding a pilot program in your area, I heard there is one going in Cape Town.
 
Ok so, I tested this thing.
You can just plug in a micro-inverter straight into a wall socket.
Must say, I'm quite impressed.
 
suPerb0b said:
Ok so, I tested this thing.
You can just plug in a micro-inverter straight into a wall socket.
Must say, I'm quite impressed.
Click to expand...

And where is the micro inverter getting its power, a solar panel? And how is it helping you with Eskom? Does it help when being loadshed? Does it somehow make you electricity use (and thus power bill) less?
 
I hope you arent on pre-paid because those meters cant differentiate between current direction.
So if you generate and have a pre-paid meter then your credit will go down faster!
 
supersunbird said:
And where is the micro inverter getting its power, a solar panel? And how is it helping you with Eskom? Does it help when being loadshed? Does it somehow make you electricity use (and thus power bill) less?
Click to expand...
It is plugged into my 300W solar panel.
It does not stay on during load shedding (I thought it would), it actually switches off as part as a safety feature.
So for now, it will reduce my power bill.

biometrics said:
Link to the product?
Click to expand...
http://www.sustainable.co.za/omniksolar-m248-300w-micro-solar-inverter.html

Just a word of caution about Sustainable.co.za. Their customer service is terrible. I made the order online and paid with credit card. After two days there was still no change on my order. I phoned in to ask what is happening and only received cocky attitude. Right after my call my order was released for delivery.
I also sent them two emails asking about another product. That was almost two weeks ago and I still have no response.
 
suPerb0b said:
Ok so, I tested this thing.
You can just plug in a micro-inverter straight into a wall socket.
Must say, I'm quite impressed.
Click to expand...
Doing this for a while and, but using a ups plus 2 batteries.

Remember doing this at own risk:D

Enjoy it, since it's plug and play
 
Good thing I did a search before posting this.
Just found this one on BidorBuy - R8 500
DIY Solar Power System

How does it work? The system consists of a 300W PV-panel, which is connected to a 300W micro inverter, which is plugged into a wall socket. While the sun shines on the panel, it produces electricity, the micro inverter converts the direct current (DC) to alternating current (AC) at a slightly higher voltage than ‪#‎ESKOM‬, which means that the electricity from the micro inverter is used.

This system is designed to save you money by generating your own electricity for free. It is designed to shut down during ‪#‎loadshedding‬ , by law, by means of its anti-islanding function. This system can form the basis of a much larger solar system that will be able to carry you through #loadshedding.
Click to expand...

My first reaction was - 'You want me to do what?' But some quick research showed this to be a valid product - http://www.evolt.co.za/ using a Microinverter by Renesola.
 
So awesome to hear people embracing the idea of making their own electricity with micro-inverters, saving money every day! Yes, our system above, mentioned by suPerb0b, works perfectly and we invite anyone who is interested to a demo to show how it works. In Cape Town, that is! ;) If you are interested, you can email me on [email protected]
 
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eVolt, That bid or buy advert claims R200 savings per month from a 300W system, how do you figure that? My calculations (being excessively generous) show that you would need an Eskom tariff of R3.58/kWh for this to be true. I'm not saying this is a bad product, in fact renesola is a well referenced supplier of modules and inverters (although they've had hiccups like the rest of the tier 1 manufacturers). just let's not get carried away with energy savings figures.
 
Hi ElecEng, let me explain how the figure of R200 was reached.

Firstly we take the NASA average solar radiation for the year in kWh/m2/day [1],
(Using Cape Town, this takes into account hours of sun/day and geoposition)

[table="width: 500"]
[tr]
[td]J[/td]
[td]F[/td]
[td]M[/td]
[td]A[/td]
[td]M[/td]
[td]J[/td]
[td]J[/td]
[td]A[/td]
[td]S[/td]
[td]O[/td]
[td]N[/td]
[td]D[/td]
[/tr]
[tr]
[td]8.17[/td]
[td]7.3[/td]
[td]5.91[/td]
[td]4.3[/td]
[td]3.09[/td]
[td]2.64[/td]
[td]2.85[/td]
[td]3.67[/td]
[td]4.92[/td]
[td]6.46[/td]
[td]7.68[/td]
[td]8.18[/td]
[/tr]
[/table]
We then use the size and efficiency of the Renesola 305W to calculate the energy produced per month.
(Renesola 305W = 2m2 @ 15.7%)
[table="width: 500"]
[tr]
[td]J[/td]
[td]F[/td]
[td]M[/td]
[td]A[/td]
[td]M[/td]
[td]J[/td]
[td]J[/td]
[td]A[/td]
[td]S[/td]
[td]O[/td]
[td]N[/td]
[td]D[/td]
[/tr]
[tr]
[td]79.53[/td]
[td]64.18[/td]
[td]57.53[/td]
[td]40.51[/td]
[td]30.08[/td]
[td]24.87[/td]
[td]27.74[/td]
[td]35.72[/td]
[td]46.35[/td]
[td]62.88[/td]
[td]72.35[/td]
[td]79.62[/td]
[/tr]
[/table]
Using the Cape Town Electricity tariff of pre-paid, beyond 350KWh of 287.42 c/kWh [2].
(We use this rate, if you don't use more than 350KWh/month, this system is not for you, as it would take too long to amortize.)
[table="width: 500"]
[tr]
[td]J[/td]
[td]F[/td]
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[td]A[/td]
[td]S[/td]
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[td]N[/td]
[td]D[/td]
[/tr]
[tr]
[td]228.58[/td]
[td]184.47[/td]
[td]165.35[/td]
[td]116.42[/td]
[td]86.45[/td]
[td]71.48[/td]
[td]79.74[/td]
[td]102.68[/td]
[td]133.21[/td]
[td]180.73[/td]
[td]207.94[/td]
[td]228.86[/td]
[/tr]
[/table]
So you see, that during Summer (Nov/Dec/Jan) you are saving R200/month, the rest of the year you do not save as much.
On average, over the whole year, you save R150/month giving an amortization rate of just under 5 years (assuming no electricity increase) and an amortization rate of 4.5 years if electricity goes up at the current rate of 12.69% a year.

I have uploaded my spreadsheet to : http://www.evoltenergy.co.za/downloads/2015-10-28-amortization.xls
Please have a look, and if you see anything that I have wrong, please let me know and I will correct it.

Here is a link to the NASA site and City of Cape Town Electricity Rates

[1] https://eosweb.larc.nasa.gov/cgi-bi...a.gov&p=grid_id&p=swvdwncook&step=2&lon=18.22
[2] https://www.capetown.gov.za/en/elec...ntial Electricity Tariff Explanation 2015.pdf

Kind Regards
Peter
Evolt Energy - Technical.
Save money everyday, make your own electricity.
 
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Evolt-Technical said:
Hi ElecEng, let me explain how the figure of R200 was reached.

So you see, that during Summer (Nov/Dec/Jan) you are saving R200/month, the rest of the year you do not save as much.
On average, over the whole year, you save R150/month .
Click to expand...

How do you sleep at night with misleading advertising like this. The add clearly states save R200 + every month

Not R200 some months using the highest possible tariffs to do the calcs with.


For R8500 money can be invested way better ......
 
781882564f37b01fbd4e97bf4758c53b.jpg
 
Hi Jaws677,

Could you please tell me where you found this add, my sales assistant was incorrect in making the statement and we will make sure all occurrences are corrected to state an average of R140/month.

Thank you for pointing it out, and I sincerely apologize.

Kind Regards
Peter
Evolt Energy.
 
Last edited:
Hi Isheed_cn,

Thank you for your comment, could you please tell me why you think it's illegal?
We have consulted with certified electricians and they have all assured us that there are no electrical regulations that are being violated.
The only legal requirement, that we are aware of, is that the device have an "anti-islanding" mechanism and that the house wiring is protected.

1. The Renesola Micro Inverter does have anti-islanding, and will immediately power off in the event of a power failure.
This is to protect Eskom engineers from being electrocuted by home owners with their own power generators.
[That is why this is not a load shedding solution]

2. The standard house wiring (220V), on a single loop, is normally protected by a 20A breaker, this is to protect the wiring of the house.
If you place a generator into a plug you need to make sure that you do not exceed the 20A rating.
Circuit breakers are designed to operate in a specific direction and are less effective if you drive current in reverse.
If you drive too much current (Amps,A) through your house wiring, the wires will heat up, like a toaster, and burn.
The Renesola Micro Inverter generates 300W, which is (220V x 1.36A) which is way below the 20A current limit.
To be absolutely safe, we recommend that a 5A breaker be connected to the output of the Renesola Micro Inverter,
wired the correct way around, to protect the house wiring.

At 300W (220V x 1.36A) the Renesola Micro Inverter will not be able to supply power (voltage x current), that is in any way, able to put your house wiring at risk.

It will be able to reduce your daily consumption, by producing electricity, while the sun shines, every day.
With no complicated wiring, and no expensive roof mounting requirements, all it needs is a place in the sun and a nearby wall socket.

Thank you
Peter
Evolt Energy.
 
I'm not talking about anti-islanding. It is illegal, as you are not allowed to connect any equipment that can feed back into the grid (i.e. generation) unless you have explicit permission - ie have signed up and passed SSEG requirements.

This includes electrical diagrams submitted to council.
Council investigating the install.
Electrical engineer signing off on said install etc etc.
Its an onerous process, and not one thats viable for a single micro inverter + panel, or even a bunch of them.


There are 2 options for SSEG:

Sans feedback -
You would need a device to prevent any feed of generated energy in excess of usage at the meter, plus fulfil the SSEG requirements.

With feedback -
Sign up for the SSEG + daily rate charge (R14 a day + bill), and fulfil the SSEG requirements.

Other municipalities have different rules, and may possibly be used.

In Cape Town though, its likely a non-starter.

Again, this is illegal to use in Cape Town, unless under very specific circumstances.
 
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