Sunny or WIndy Boy ?

[Jens]

With the US dollar approaching par with the Canadian dollar, the issue of a grid tie inverter seems to come back to mind.

The plan would be to take 240VAC, rectifying it, filtering it and feeding it to the inverter which then feeds the grid.
I am pretty much set on SMA because of perceived quality. The thing I am not sure on is how the Windy Boy and the Sunny Boy differ. I am assuming the onboard algorithms are slightly different but would that matter in my particular application ? Has anybody ever looked into that ?

Prices for the SMA SB5000 seem to range from about $4200 down to $3060 for the same product. Gut instinct tells me I am getting exactly the same thing no matter what price - all service or support would go back to SMA anyhow. Is there any reason to pay more ?

Anybody have any particular feelings (either pro or con) towards a particular SMA dealer ?

Jens

[bschwartz]

Jens,

I'm looking to do exactly what you are describing.  I have no input at this time, but will be following closely......  I'm curious to know what type of filtering will be needed.  The 240V rectified will be roughly .707 x 240 = 169v if my math memory serves me.

[BruceM]

Jens, I suggest that you look into large surplus transformers that you can use for a filter inductor.  Your power factor is going to be crap with only capacitive filtering.  I'm using a 1100VA torroid for a 10 amp 150VDC charger filter, which I got on ebay. I found I could use the primary winding without saturation.

Best Wishes,
Bruce

[mike90045]

If only those 2 choices, I'd select Windy, as it is expecting to see rectified wild AC.  SunnyBoy wants pure DC

Another option is the Xantrex XW series of off grid/intertie inverters. the 6048 expects 48VDC on input, a small battery bank will filter your rectified wild AC
Xantrex XW6048-120/240-60 Hybrid Inverter-Charger  http://store.solar-electric.com/xaxwhyin1.html   6KW output @ 240VAC
specs  http://lib.store.yahoo.net/lib/wind-sun/XW-Inv.pdf

[WGB]

What are you wanting to do all this for Jens?
Just to do it for fun, or are you looking to make a buck?
Around here if you could run the inverter at full capacity it wouldn't make 50 cents an hour.

[mike90045]

I think you have to use the windy boy.  Sunny boy is expecting pure DC, Windy is expecting Wild AC, 3 phase rectified.

[Carlb]

FYI  I just installed two sunnyboy 5000's today.   Don't even attempt to lift one of these on to its mounting bracket alone.  The inverter weighs 145 lbs.   I hope to have them up and running buy the end of the year. 

[LowGear]

I noticed they have the same peak efficiency.

http://www.sma.de/en_US/products/grid-tied-inverters/sunny-boy/sunny-boy-5000us-6000us-7000us-8000us.html

http://www.sma.de/en_US/products/wind-power-inverters/windy-boy-5000us-6000us-7000us.html

How do the other specs compare to you more knowledgeable bloggers?  I wonder if you can hook solar panels into the Windy Boy?

Casey

[Ian]

As Jens said. (But adding a little more info.....)

All the SMA inverters have the full suite of firmware installed into EPROM at time of manufacture. When the inverter is shipped from the factory, generic settings are dialled in to select whether it is a "Sunny Boy" or a "Windy Boy" and the national standards for grid connection for the country it is being shipped to.

There are 3 levels of "administration". The lowest level allows the conversion of a Sunny Boy to a Windy Boy or vice versa (as well as selection of constant voltage, constant current, or off grid if used with a Sunny Island).

The second level of administration allows changes to the grid connection parameters but in order to obtain this level of administration, you have to sign a disclaimer and agree to place certain stickers on the unit to show it has been altered from standard approvals.

The third level of administration is only available to SMA and this allows changing just about any parameter (such as serial number, etc) – but crucially, also allows them to interrogate the inverter to see if the base parameters have been exceeded (such as an over voltage condition).

Regards,
Ian

[LowGear]

That sounds so smart (programs included). 

Now if I were to run PV panels during the hours of daylight and then rectified DC for a few hours in the evening would I need to be switching the inverter back and forth or would Windy Boy be "Good Enough For Government Work!"?

See http://www.microcogen.info/index.php?topic=553.0

Casey

[Ian]

Casey, the "in principle" response should be the single Windy Boy settings will work. However, unless the generator voltage and the PV voltages, and power output levels are correctly aligned it is unlikely that the system would be optimised. You would also have to play around with the "turbine curve" settings in order to get a reasonable output – but it is possible. On the other hand, SMA would tell you that the inverter has not been designed and tested to do this and they would not recommend or guarantee it. You would be on your own.....

Jens, yes, I have the "keys" to admin levels 1 and 2 but they cost me a lot of money and it is my business - so I am sorry, I will not be giving them away.

If you did obtain the keys to admin level 1 from SMA (not so difficult), you will need a computer and the free download packages from SMA plus a communications interface into the inverter. There are RS232, RS485, and proprietary interfaces available. Depending upon your outlook, these may be moderately priced or damned expensive.

I hope this helps.

Regards,
Ian

[LowGear]

Well!!! Rhymes with Hell!  SMA will not sell me the "Keys".  I've asked twice what would be the outcome from hooking up solar panels (joined to the correct voltage) to the Windy Boy but have received no feedback as of yet. 

I'm scaling back my solar generation (only so much space up there on the roof) to 4KW so I'm starting to look at Enphase for the panels and the Bill Rogers approach to home power grid tie.

Casey

[LowGear]

SMA just got back to me:

We recomend not doing this, because when the inverter is a sunny boy the inverter is set to mpp mode, which helps the inverter to track the solar array. When the inverter is a windy boy   It is in constant voltage mode.

I'm pretty much ignorant.  How's this sound to you that know what "mpp mode" really means and what impact it would have on output?

Casey

[mike90045]

MPPT is disabled, and it won't track.  It will stay at some pre-set voltage.  If you can set that voltage yourself, great, use Vmax power  x # of panels you have.  Add a volt per panel in cold weather.

[LowGear]

Not another innocent question?  Yup.  What does "track" mean? 

The panels after 8 AM will always be above 70 degrees F.  Hawaii does have downsides – really.

Casey