Solar PV Design - Oldtimer

Hi,

I am a retired professional electrician who now lives in Denmark. The Danish government has just started a Solar PV grant and I want to install an Grid-tied array. The problem is I do not have any experience installing a Solar system although it seems pretty straight forward. I just need some advice on the design of the optimal solar PV system.

I have been researching the various possibilities and I am currently leaning towards a solar PV system using SMA Sunny Boy 240 Micro Inverters. It appears that there are some big advantages to using Micro Inverters compared to a dedicated single inverter. The main one being that you can monitor each individual panel in the array rather than monitoring the entire array as a whole. (Give you the opportunity to see faulty panels and use various wattage panels in the array should it be required.)

The Danish government requires that the maximum Inverter effect is 6kWh

I would also like add a battery backup for off grid usage, especially has Denmark isn't the sunniest country in the world.

I have based my calculations on the following:

Annual Electricity Consumption (kWh): 4000

Solar Production / Year (kWh): 5300

Expected Personal Consumption: 43%

Electricity Price / kWH (First Year): £ 0.225

Electricity Annual Price Increase: 5%

Electricity Sales Price (1-10 Years): £ 0.09

Electricity Sales Price (11-20 Years): 0

Solar Panel Annual Degradation: 0,50%

Roof Direction: South

Roof Angle: 25˚

I am interested in hearing any design suggestions that you young sparks might have???

Current Considered Design (based on research):

18 x SMA Sunny Boy 240

18 x PanasonicVBHN330SJ47

1 x SMA Multigate 

1 x SMA Energy Meter

Can the SMA Multigate read the SMA Energy Meter ( Do they speak to each other?)

What would you recommend as a battery inverter for a 4-6KW battery bank for the above design?

Any improvements or recommendations to this setup?

I can see there is a certain amount of waste converting from the AC provided by the Micro Inverters to DC and back to AC for off grid consumption.

Options 2:

1 x SMA TriPower 6000TL (Any other suggestions?)

18 x PanasonicVBHN330SJ47

1 x SMA Energy Meter

What LioN battery solutions would you recommend? Some are seriously expensive but would be interested in hearing your opinions?

I hope you can help an old timer out!

Cheers!

some big holes in your numbers.

I love Panasonic, but they are pricey. Unless you have a restriceted roof space look at Solarworld 285W psnels for a good blend of quality and price.

Micro inverters are pants unless you have significant shading issues.

Batteries, expensive lettuced unless you re off gird and have a real need for them, even then look at traditional wet-cell batteries preferably located in an outside shed

Cheers Guys,

I can get a really good deal on the Panasonic panels at trade pricing but will definately look at the Solarworld panels, but yes I am limited in roof space. If I use 285w panels and with the solar insulation in Denmark I would need 22 panels to reach the 6kW mark.

The reason for the battery bank is because we can then use the solar energy on cloudy days which there are plenty of in Denmark and the reduced lighting hours. So to be able to reduce our usage of the grid a battery bank makes sence!

Canoeboy said:

Any reason your going for 18 sunny 240s mini inverters behind the panels ? Is the array of vast different orientations and angles ? It looks like you have 18x330watt panels ?

Click to expand...

Yes, If I use 18 Sunny Boy 240 micro inverters then I can monitor each panel individually via MPPT, but I can see now you say it they have a lower power output than the Panasonic panels provide.

I am going to try and find a PC I can borrow so I can install the SMA Design software, shame they don't do a Mac version!

Any reason for choosing the SMA 5000TL over the SUNNY TRIPOWER 6000TL?

Thanks for the help boys!

You can also monitor individual panels with the solar edge system- you're not incurring the D.C-A.C-D.C conversions. 

Dont know if it's cost effective- I do recall the solar edge inverter being vaunted as one of the most efficient available. 

solaredge is up the top end, but not as good as SMA, what they claim is enhanced performance from individual panels / shading. Can't say I'm convinced as the school systems I monitor are 1/3 Solaredge, and they aren't outperforming Fronius or SMA

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