SMA Sunny Island Questions

Hi guys,

I'm planning on becoming less dependent on the grid system. The plan is to island my supply between an SMA Sunny Island and a grid-tied inverter from my PV generator. 

The question I have is do I need to buy an SME Grid Tie Inverter or will any Grid Tie Inverter work with my Sunny Island? I have a 6KW ABB Aurora which I would like to use with the Sunny Island although I fear this may not be possible.

I'm planning to fit this myself (qualified sparks) and don't think I need to speak to the DNO as I do not intend to export anything back onto the grid. At both ends I have battery banks and have an excess of solar for my needs (6kw). I'm using E7 to charge up my batteries when there is not enough sunshine (timer/contactor for E7 period). I also have a large-ish (5KW) UPS which supplies electronics during the day time with the energy I have stored from the E7 rate but this would be going when the SB Island is up and running. I have downloaded their material but cannot find any reference to which GTI's are suitable for the Island. 

Thank you in advance

The Sunny Boy Island is an AC coupled system so the PV inverter used shouldn't matter. Though a SMA of some sort would probably be better.

Thanks Barx that's good to know. I'm interested to know your viewpoint on why an SMA inverter is better; in what way? The efficiency of my ABB is pretty good and I don't want to have to buy another inverter unless it makes financial sense.

Just because the SMA gear will be able to talk to each other and will most likely all operate through one gateway. Sunny Portal?

The Sunny Island is designed for the retro fit market

SMA are better made than ABB. Which inverter is better for your system will vary according to the panel array, however, if you have an AB already, then there is little point in buying a different unit. The one thing you are possibly missing the point on though is that unless an inverter is designed to be off-grid, then it needs a mains voltage present to work as part of the G83 / G59 requirements. If you are planning an off-grid array, you need off-grid inverters.

Thanks Binky. I need to better explain my intended layout. I thought I could use the SB island to create a sine wave from a battery bank that would allow the GTI inverter to engage. I thought the purpose of the SB Island was to create an island of AC between the SB island  (which controls the DC side ) and the GTI but as it's an island AC is only flowing between these two devices. The SB Island is connected to the grid only to allow the battery bank to charge in the absence of sufficient light. I hoped that when the SB Island was powered it would provide the sine wave to engage the GTI. I do not intend to export anything to the grid but I can receive if needed to charge my batteries.

If go down the route of purely DC off grid I'm losing the advantages of high string voltages and maximum efficiency gained by AC MPPT's. I need to provide a drawing but I'm on my mobile at present. Thanks for the info so far we're getting there.

Electron Farmer said:

Thanks Binky. I need to better explain my intended layout. I thought I could use the SB island to create a sine wave from a battery bank that would allow the GTI inverter to engage. I thought the purpose of the SB Island was to create an island of AC between the SB island  (which controls the DC side ) and the GTI but as it's an island AC is only flowing between these two devices. The SB Island is connected to the grid only to allow the battery bank to charge in the absence of sufficient light. I hoped that when the SB Island was powered it would provide the sine wave to engage the GTI. I do not intend to export anything to the grid but I can receive if needed to charge my batteries.

If go down the route of purely DC off grid I'm losing the advantages of high string voltages and maximum efficiency gained by AC MPPT's. I need to provide a drawing but I'm on my mobile at present. Thanks for the info so far we're getting there.

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My understanding is that this IS possible with the Sunny Island. Says so in the manual too.

as per bottom of this page.

http://www.sma.de/en/products/battery-inverters/sunny-island-60h-80h.html

wasn't suggesting a DC only off grid, so I'm guessing you are hoping that with the SB outputting AC, the ABB will see that as mains voltage? Not too convinced that will work, as neighbouring PV systems somehow don't interfere with each other, so they must be able to detect inverter AC as against mains? Got to be worth trying before replacing the ABB though

To quote the manual, in case you haven't seen it.

3 Product Description

3.1 Sunny

Island

The Sunny Island is a battery inverter and controls the electrical energy balance in off-grid systems, in battery backup systems, or in systems for increased self-consumption. In a battery backup system, you can also use the Sunny Island for increased self-consumption.

Click to expand...

I could be reading it wrong. I have a tendancy to do that

Obviously this stuff is still very green over here but I have also seen a video of a system in AUS with this exact setup and the guy was running it at recording time with a power outage.

Keep us up to date with it. It won't be long before we are all installing it......

binky said:

as per bottom of this page.

http://www.sma.de/en/products/battery-inverters/sunny-island-60h-80h.html

wasn't suggesting a DC only off grid, so I'm guessing you are hoping that with the SB outputting AC, the ABB will see that as mains voltage? Not too convinced that will work, as neighbouring PV systems somehow don't interfere with each other, so they must be able to detect inverter AC as against mains? Got to be worth trying before replacing the ABB though

Click to expand...

.. and therein lies my original question and the conundrum!

I have a myriad of options.

1) I commit to the Sunny Island and then find it doesn't work with the ABB.

2) I commit to the Sunny Island and have to buy a suitable SB GTI

3) I use cheaper Taiwanese Off grid inverters with a parallel kit and have yet more batteries.

Looks like I need to call SMA and ask tomorrow. 

Here is how I proposed to install.

View attachment Solar System.bmp

Thanks Barx, you replied while I was still trying to upload a picture. In essence, what I am trying to achieve is the following:

1) I would like to be as self sufficient as possible.

2) I do not want to pay a standing charge for metering, only for consumption.

3) Now that the government has ruined the PH industry due to FIT removal, there are a lot of cheap GTI's on the market place. I bought my 6kw ABB new for £250. If I can create an island without exporting anything, then effectively I am keeping my own generation for my use and I do not need to comply with the majority of regulations other than 17th Edition and planning etc. Solar panels are cheap as a lot of companies are liquidating so I think it is a good time to invest.

I will update the thread when I have spoken to SMA, once again, thanks for the input it is a very useful website  :Salute  

I would call the ABB technical helpline and see if you can 'off grid' that unit - it's all in the software which can be reset.

binky said:

I would call the ABB technical helpline and see if you can 'off grid' that unit - it's all in the software which can be reset.

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That's an interesting avenue. It would be a great commercial decision as it would help keep customers and entice future product sales. I will mention that.

Canoeboy said:

As far as i know - And according to my missus thats very little, the AC Inverter (ABB or SMA or whatever) wont care at all 

Take a look at page 10

http://files.sma.de/dl/20472/FSS-UK-IA-en-20W.pdf

Whilst page 10 shows all SMA kit i did speak to technical about using the sunny island with a fronts inverter and they said that the sunny island wouldnt know which inverter was on the pv

Ill be installing one in a few months time so will know more then once designed, that will be a fronts inverter with an SMA sunny island and a bank of 6V traction batteries (trojan)

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Excellent! That is exactly what I was looking for. Much prefer to do it this way (couldn't find that info despite looking) as the alternative was a several Korean units in parallel and a lot of DC heavy cables.

As my log cabin is 150 metres away from the house and will support 24 panels I did not want the losses. This way I am just returning the AC to the main house via a 6mm SWA and the SB Island and a set of batteries will reside in the house (basement).

Guys, thank you very much  Guinness