Hi, This is my first posting. I just went to check out SMAs new program that will help you calculate how many of any given module you can string together and feed into a Sunny Boy, very handy. http://www.sma-america.com/
I have installed at least a few dozen Sunny Boy's and the only Trace ST I ever touched was a reinstall for someone elses customer and that was his third install of a very flawed product. Trace has always had a policy of denial since the beginning. If any of you remember the old C-30 charge controller, it had a relay that could not survive 30 amps at 24 volts or even 25 amps and the techs would say they had never run across that problem before. Sure!
One of you said " Gotta love the SW" I would not agree with that at all. Every time I accidently bump the DC disconnect and the stupid thing erases all the settings, I curse their engineers. Believe me, the list is long on SW gripes among those that deal with the SW regularly.I do have faith that Xantrex or someone will get it right.
One of my suppliers mentioned that the Sunny Boy makes up 85% of the grid-tie units in California, according to CEC information.
I recently put in an SW with the GTI and in the same 24 module KC-120 many people use, I have not seen anything over 1800 watts and with the SB I would usually see over 2000. I dont know how much that GTI eats up but it cant be good.

Comparing the sunnyboy to the SW series is apples and oranges ...

The SW has no mppt ... My understanding is you set the charge voltage and that's it. You will easily lose 20% this way.

I'm not sticking up for the product , I have never used on personally. I'm just trying to keep the technically facts straight

Two other thing to point out ..

The sunnyboys are documented as to reporting 2-3% over actual power generation levels. The software may report 2000 watts but it's more likely 1950 ...

I know, I have dedicated data-loggers on my system now and have tested 4 different SB2500's ... they ALL report high

SMA basically shrugs there shoulders and says " no one complains that the units read high".

I until recently bacsically aggreed , but in my most recent testing found out that the power-limit on the sunnyboy would kickin at just over 2400 watts , when the XR would work right-up to 2500 watts [img]images/smiles/icon_wink.gif[/img] [img]images/smiles/icon_wink.gif[/img] . The Sunnyboy was reporting 2504 watts but since it reads high (and all safety stuff is based on what it reports) it would limit to early.

Here in florida , this is a real issue since edge of cloud is a very real effect.

The inverts regularly go to power-limit between 12:00-2:00 between the cat and mouse with the clouds , leaving that 100 watts for 2-3 minutes is real watts being lost. (or Gained [img]images/smiles/icon_wink.gif[/img] [img]images/smiles/icon_wink.gif[/img] )

Also the Grid Voltage cut-out on the sunnyboy is set at 262VAC , Not 264VAC , twice , in the last two days the sunnyboy drop off for 5 minutes and the XR [img]images/smiles/icon_wink.gif[/img] [img]images/smiles/icon_wink.gif[/img] didn't since the voltage poped upto 263 volts.

They just put a new 3 phase line out on the street and havent tweaked it yet, I had the Electirc company out and they tried to feed me a line that was normal , I said no way and showed them a graph of the AC voltage and they then quietly disappeared. Today the Voltage is down to 249 (was 259) so the talk of changing the tap on the sub-station transformer has been done

[img]images/smiles/icon_razz.gif[/img]

Just to clarify the 2% comment I made. Our spec on the power measurement is +/- 4%. We normally try to target the center of the production bell curve at 1 to 2% high because the feedack we hear is that people prefer it to read a little high to a little low. I think tthis is a purely psycological issue rather than a technical one.

I think the XR's Henry has are not representative of most of those in the marketplace.

As far as the 262 versus 264 arguement goes I think it does not matter in a real world kWh/yr measurement. Anything above 252 is outside of ANSI range A and the utility is required to come out a reduce teh voltage (this may vary by location but I do not think so)

We chose to be a little conservative on the voltage limits. This way we could insure we did not ever go over 264 and give the utilities more ammunition to oppose PV. Others have been less conservative on anti-islanding and created huge problems with utiltites. Just ask anyone in NY, LA, or..

Hi John !!

The sunnyboy IMHO is still the best of breed of the current crop of grid-tie inverters.

When the updated XR's start-rolling out in Jan 2003 (software and hardware changes designed by me on contract with Xantrex for disclaimer), the differences between the units will be much smaller.

My comments on the power reading aren't really meant as a knock on the sunnyboy but it is to establish what will now be the differences between the Xantrex vs SMA products

The yield differences are now down to the difference of the XR two stage design vs. the sunnyboy single stage design. This means in real world testing a differnance of 1% to 4% depending on the power levels the inverter are run at. (Yokogawa 1030 verifed FYI)

The power cutoff is real ... the SMA boxes as good as they are do limit early and go offline early in high line conditions that real world people are facing.

Your are correct you can get the power company to make adjustments , but the fact remains , the sunnyboy is not meeting the UL1741 highline VAC spec which is 264 volts.

As I see things shaping up the new XR will be a strong candidate in systems that have large arrays and will run above 2KW for a large part of the day. Cooling performance has been dramatically improved , the mppt tracking is now as good as the sunnyboy.

The issue of single string vs multi lower voltage strings is really coming to a head with the new Sharp 165 watt , 24 volt panels

The sunnyboy match’s excellent with 120 watt 12 volt panels but the sharps are not matching well to the 2500. This is one of the few problems with string inverters , that being the number of panels options is not very wide when compared to and XR style inverter.

So from a user stand point , is it worth 2% in yield (sunnyboy advantage) to have the flexibility of 4 to 24 panels configurability of the XR. The market will give us this answer.

And Yes , SMA now has 3 choices of wattages ... but it's still the same issue. Do you want the ability to start small and grow or match the invert to the initial installation but that's it.

You and I both know John that for SMA to resolve both the power limit and VAC high line issue would be minimal. I hammered on the XR for it’s issues it had and it will be a better product as a result. Hopefully SMA will listen to the issues I and others are rasing and make further improvements for all I wish to see is the best possible products for the PV community.
[img]images/smiles/icon_smile.gif[/img]

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by Solar Guppy:
(snip) ... for all I wish to see is the best possible products for the PV community.
<HR></BLOCKQUOTE>

Hear! Hear! Could not have said it better.

-Roger [img]images/smiles/icon_smile.gif[/img]

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by Solar Guppy:

So from a user stand point , is it worth 2% in yield (sunnyboy advantage) to have the flexibility of 4 to 24 panels configurability of the XR. The market will give us this answer.
<HR></BLOCKQUOTE>


As someone who has a small system (4 Sharp 165W panels) this is indeed a factor. I can build up my system (XR) 2 panels at a time as I can afford. While the Sunnyboy may technically be a better inverter, it was never an option for me because of the high initial panel count and limited string configurations. Of course I'm probably in the minority by building up slowly, however there are at least a few of us that this is an issue.

[ November 06, 2002: Message edited by: Mark Lopez ]

Good points Henry. We've enjoyed working out the cobwebs with you and the new product is going to be a joy to field.

Hi boB! I still cannot seem to get my hands on one of your MX60s!

Tobin
Xantrex Tech

>Hi boB! I still cannot seem to get my hands >on one of your MX60s!
>Tobin

That's because they're out in beta test right
now... About 15 or so of them I think. But I bet you guyz will have one real soon.
Just some slight tweaking here and there and,
Voila! (Wouldn't it be nice if it really were that simple?)
Say hi to everyone up at the Lazy X!
boB Gudgel
[img]images/smiles/icon_wink.gif[/img]

[ November 16, 2002: Message edited by: bob gudgel ]

A friend & I had in common a fixed-roof, same-pitch, close-to-same orientation Kyocera 2880w array w/ a SB2500U. His KC120x24 system averaged about 5-7% more generated output than my KC80x36 system, which had to be wired as two KC80x18 arrays in parallel. After postulating about differences in lattitude (he's many degrees south), altitude (he's 3k' higher), wiring (his is simpler) or the effects of paralleling two arrays (versus his single string), I've finally rectified the situation :

My Sunny Boy was always running close to the SB low voltage threshold of about 230-240vdc when things got sunny & warm and my typical sunny output never ever broke through the 2kw barrier (usually 1.7-1.8kw). So I got lucky on eBay and picked up a pair of KC80s for a decent price to increase the inverter input voltage a tad. My initial measurements showed that I was now getting 300-400w (AC) more from only an additional 160w of PV panels !! How could this be, especially at this time of year when the weather is still cool ?

What I didn't realize before was that when the SB was approaching its lower DC input limit, it was clipping the amount of power from the PV array by skewing the MPPT! Now that the SB DC input voltage is up around 250-260vdc, I'm seeing AC power generated easily 10% above the 2kw threshold. So far today I've seen the SB get up to 2450kw - it would never, ever get that high before, even though the efficiency ratings of the SB and standard panel derating said that it should be getting up there.

The string calculator on the SMA website and the specs of the SB appear to be very accurate, and the sizing charts for strings of 18,19,20 KC80 modules tell the story of what I was seeing firsthand - before & after the panel additions.

So, for the effort of adding 160w of panels I'm getting about 300-400 kw (AC) more out of the system during sunny periods - not a bad deal !

-- Larry Hale

P.S. As the insolation increases, the SB will track down the MPPT point to a minimum voltage value. This seems counter-intuitive, since the IV curves for any PV panel doesn't show this story, so it must be a function of SMA's MPPT algorithm. In cloudy conditions you'll see the same drop in voltage, too. So beware about that and hot temperature deratings as well (both of which are taken into consideration on SMAs website string size calculator).