If you check the SMA website (Sunnyboy manufacturer, maker of Sunpower's relabeled 6000m) they have a sizing tool available. It says that the 3 strings of 10 Sunpower 225's work. This seems to contradict some of the advise given in this thread.

There are 2 advantages of the Sunpower monitoring over other monitoring:

1. Indoor remote display that can be placed in a convenient location and give you the ability to check your system performance at a glance.

2. You can check your system performance from any computer using the website.

GT-View gives you a great amount of data regarding you system (My father produces detailed graphs and charts for his 20kW system on it) but it might be a little overwhelming for joe homeowner who just wants to make sure his system is working. But then again the price is right (Free)

The SMA string sizer has errors/bugs in it. I sent the info to SMA , they never responded

Use the Xantrex String sizer select a GT5.0 and the panels you are to use and compare the data.

One error I remember is that the SMA tool doesn't take into consideration running below the units minimum voltage input, is just scales the watts as V*I when in fact is not linear in the drop. Another poster in Mass. has an SMA installed system with to few panels in a string an was only getting 1/2 the nameplate watts. on the SMA string sizer it look OK

Well, here's the scoop from todays visit with the design engineer.

For this area, he says that to figure out the realistic output, you would multiply the maximum output (30 * 225 watts = 6750 watts) by .88. This gives us 5940 watts, under the 6000m inverters limit. He says that if we had perfect conditions, the panels MIGHT produce more watts than the inverter could handle, but he claims that it my happen one or two days a year and moreover does NOT hurt the inverter in any way. (comments on THAT?) He said from his experience in real-life SoCal conditions, that he wouldn't hesitate to install the 6000m with my system.

They are going to give me a price on a 7000m inverter which would alleviate any possible problems AND leave a little room for adding 3 more panels, if I should choose to do so later. If the difference is only a few hundred dollars, I'll go with the larger inverter.

As far as the monitoring system, I want to stick with Sunpower's setup, because it's just what I want. They're still beta-testing the units, so I told my engineer to call Sunpower and beg them for one more unit. I'd rather have them install everything at the same time. We shall see if the guy is any good at sweet-talking Sunpower.

Anyway...that's all for now. As always, comments are appreciated!!

JimmyD

I guess there is an argument both ways, on one hand the 6000m will be working harder and maybe more efficient than a 7000m, particularly at the low end of the curve which will be greater with the 7000m. On the other hand, the 6000m will lose some watts during the times that push your system over the inverter max. For sure that will happen, and more than just one or two times per year. I am in South Orange County, Ca not that far from SD, and my setup has hit max watts probably 20x in the 9 months I have been online. Of course, it has been sitting at 4,100 - 4,300 watts peak during this last couple of months for the most part due to high temps, but even recently we had some clouds blow in that created the right conditions to max the inverter for a bit. Your setup will be more so than mine, since using the .88 factor I am at only 4,878 watts max which gives me more headroom than you will have.

I say, make them throw in the 7000m as part of the deal at your current contract price

Thanks to everyone for the information. After discussing the system with my installer, I'm upgrading to a Sunpower 7000 watt inverter so I don't lose any power AND so I can sneak a few more panels if I should choose to do so later.
We also managed to get in on Sunpowers beta test for their new system monitoring hardware/software that they're working on. It basically consists of a small in-home monitor that shows whatever the LCD display on the inverter itself shows. And then there is a wireless hookup that feeds to the internet so I can access current and historical data on my system using a graphical display. That part is accessible from anywhere, since it's internet based. The company ALSO claims that they'll set up silent monitoring of your system and should the output drop for unknown reasons, they can have the installer go out and check on it. I seriously doubt they'll use the information for THAT reason, but from the companies perspective, getting to monitor your equipment in the field would have to be good for demographics use, etc.

I'm setting up a web site for pics etc. during the installation. When it's ready, I'll post the link here for anyone interested.

Have a good one!!

JimmyD

i think you made a good move even just for the expandibility alone and should you get more power than the other inverter would pass it won't be held back. the monitor sounds good too and i'm looking forward to reading how it does for you.

I'm making a web-page to chronicle the solar system I'm putting up. If you want to check it out, the link is:

http://www.jjhamilton.com/solar.html

I've never designed a site before, so feel free to let me know if there are any bugs/bad links/or general problems viewing it.

More to come!

JimmyD

you better check that those power lines i see won't cast a shadow on any of the pvs, especially in the winter months.

Its a shame to have to take out those palms! ... maybe you can transplant them to the side or back yard. I had to move a queen palm last month as it was growing so fast in a year it would have started shading one of my arrays, I moved it to another place in the yard instead of having it removed

I know! That was the hardest decision to make, since I planted them all and I love the way they look. But we're going to do a complete re-do of the front landscaping, and the palms won't fit with what we want to do, so.....they go.

I tried to find someone to buy them, but around here, Queen Palms are a dime a dozen and the 2 King Palms that are being removed apparently die almost 100% of the time if they're transplanted.

Once they're gone, I'll post a good 'after' pic.

JimmyD