Sanity Checking + Advice on SolarEdge

[aleenoor]

This is normally a 2014 NEC requirement, not 2011. Where are you seeing the need for it?

Not sure If I need to comply with 2014. Marc's paperwork points towards 2011. If I don't , the Kaco is a cracking deal.

I see that Kaco comes with a separate add-on for DC disconnect. Can that be installed seperatly ? Within 10 Ft of the array ?

What panels are you using I your system.

[sensij]

Not sure If I need to comply with 2014. Marc's paperwork points towards 2011. If I don't , the Kaco is a cracking deal.

I see that Kaco comes with a separate add-on for DC disconnect. Can that be installed seperatly ? Within 10 Ft of the array ?

What panels are you using I your system.

No, the DC disconnect that comes with it is installed together with the inverter. You can google "Rapid Shutdown Box" for options for remote DC disconnects that are located within 10 ft of the array, but I don't think one will be required for you as long as you get it installed before the end of the year. They typically run close to $500 for 2 strings by the time you add the disconnect, the actuator, and the additional wiring.

I'm using Canadian Solar CS6K-280M's. I had found the Hanwha Q.Plus G4 series at some very good prices too, but those panels are slightly larger than standard 60 cell and I would have run into clearance problems.

[aleenoor]

No, the DC disconnect that comes with it is installed together with the inverter. You can google "Rapid Shutdown Box" for options for remote DC disconnects that are located within 10 ft of the array, but I don't think one will be required for you as long as you get it installed before the end of the year. They typically run close to $500 for 2 strings by the time you add the disconnect, the actuator, and the additional wiring.

I'm using Canadian Solar CS6K-280M's. I had found the Hanwha Q.Plus G4 series at some very good prices too, but those panels are slightly larger than standard 60 cell and I would have run into clearance problems.

Thanks Sensij, where did you find out about the rapid shutdown requirements not applicable in 2017. Isnt this dependant on your city/ county codes ?

I like the qcells, 300 or 290 ? If you don't mind me asking, where did you find them and how much. Thanks.

[sensij]

Thanks Sensij, where did you find out about the rapid shutdown requirements not applicable in 2017. Isnt this dependant on your city/ county codes ?

I like the qcells, 300 or 290 ? If you don't mind me asking, where did you find them and how much. Thanks.

It can be, although the fact that FL as a whole is still on 2011 means that you are probably OK. See the link in this post. It isn't common for cities or counties to run ahead of the state code, but it is always worth double-checking to see if there are local regulations that are applicable.

For the panels, look here:

http://www.solarreviews.com/distributors/acosolar-inc/

They don't always have everything listed in stock, but it is worth asking.

[SunEagle]

It can be, although the fact that FL as a whole is still on 2011 means that you are probably OK. See the link in this post. It isn't common for cities or counties to run ahead of the state code, but it is always worth double-checking to see if there are local regulations that are applicable.

For the panels, look here:

http://www.solarreviews.com/distributors/acosolar-inc/

They don't always have everything listed in stock, but it is worth asking.

For that matter I would expect some dark corners of my state of FL to still be following the 2008 NEC.

[aleenoor]

It can be, although the fact that FL as a whole is still on 2011 means that you are probably OK. See the link in this post. It isn't common for cities or counties to run ahead of the state code, but it is always worth double-checking to see if there are local regulations that are applicable.

For the panels, look here:

http://www.solarreviews.com/distributors/acosolar-inc/

They don't always have everything listed in stock, but it is worth asking.

Thanks Sensji, btw Renvu.com has great prices on SE.

[aleenoor]

I can't for the life of me figure out how to send you a PM, and I can't remember if recommending solar installers in the threads is in line with the forum rules or not, lol. Let me know and I'd be happy to let you know who I used. I highly recommend them.

That said, it's hard to say whether any given installer would be willing to work with you if you provide all the equipment. These guys make most of their money on marking up the equipment, not on a couple days worth of labor, so you might be surprised what kind of installation quote you get if they're even willing to install hardware you provide yourself. Said a different way, with made up numbers, if they can make a 50% profit from some "regular" customer down the street, why would they take your job where they'd make nothing on parts and only 20% profit on labor? Both jobs keep one or more of their limited install crews busy for a couple days, so it's an opportunity cost for them. That said, you'll never know if you don't ask!

Thanks Marc,
Yeah, I couldn't figure out PM on this site. Is there such a thing on PVOutput ?

[aleenoor]

[Deleted accidental duplicate post ... also continued original post which got cut off in the middle due to certain symbols?]


You can also use the PVWatts site to compare production of identical arrays pointed South vs. West, but from the data I pasted above, you should expect your west-facing panels to be like my friend's east-facing panels, and produce ~81% of the power produced by your south-facing panels. This all assumes zero shading, as neither mine nor my friends installation has any shading.
I hope this is useful info for you, please let me know if I can be of any further assistance.
Thanks,
Marc

Marc, Very helpful indeed. I played around with PV watts . I think it differs from your real-world output loss. Here are the key things I picked up. FYI: this was done for 32835 as Orlando Airport Weather data.

According to this, East Facing is better than West facing by 2.5% @ 6:12 or 1.9% at 4:12.

Slope	Direction	Azimuth	KWh	%
6:12	S	180	15975	100.00%
6:12	E	90	14009	87.69%
6:12	W	270	13599	85.13%
4:12	S	180	15808	98.95%
4:12	E	90	14357	89.87%
4:12	W	270	14055	87.98%

However, with up to 20% drop in performance for a west facing array, I am really considering paying more for a higher efficiency panel and sticking to South. I also expect minimal zero due to all panels being on a 2 story roof. Some trees across the street might cast some shade very early in the morning.

[sensij]

Thanks Sensji, btw Renvu.com has great prices on SE.

Yes, that is who I was shopping against. I ended up buying from Tandem, below is their quote, with Renvu's price in yellow.


Quote.JPG

[J.P.M.]

Marc, Very helpful indeed. I played around with PV watts . I think it differs from your real-world output loss. Here are the key things I picked up. FYI: this was done for 32835 as Orlando Airport Weather data.

According to this, East Facing is better than West facing by 2.5% @ 6:12 or 1.9% at 4:12.

Slope	Direction	Azimuth	KWh	%
6:12	S	180	15975	100.00%
6:12	E	90	14009	87.69%
6:12	W	270	13599	85.13%
4:12	S	180	15808	98.95%
4:12	E	90	14357	89.87%
4:12	W	270	14055	87.98%

However, with up to 20% drop in performance for a west facing array, I am really considering paying more for a higher efficiency panel and sticking to South. I also expect minimal zero due to all panels being on a 2 story roof. Some trees across the street might cast some shade very early in the morning.

For better cost effectiveness, go w/the south orientation, which will almos6t always give a greater annual output per installed Watt, use standard panels, and pick up the 20% area efficiency advantage via conservation measures.

As for "high efficiency", I'd keep in mind that is an area efficiency, not a production efficiency. For the most part, and usually within some few %, all equal (electrical) size arrays that use known, and decent quality components, including Sunpower and most any other quality mfg. product, will, in the same location, orientation and duty, produce about equal annual output for probably as long as you'll own a system. Snoop around PVOutput.org and compare outputs for similar orientations in your area for some corroboration on that.

Suit yourself, but if you have sufficient room, using "high efficiency" panels will increase system price by 20-25% per installed Watt, but probably won't get you much, if any, benefit beyond bragging rights. If saving money and reducing an electric bill are goals, and you're cramped for space, one alternative is to first pick up a 20% or so bill reduction via conservation and then supply the remaining desired bill reduction using fit for purpose standard panels.

Sunpower's good stuff, but so is a Mercedes. Panels are a commodity these days. A Ford and a Mercedes are equally good grocery haulers. Solar's an appliance, not a lifestyle. Pay your money, take your choice.

Take what you want of the above. Scrap the rest.

[Magius]

I played around with PV watts . I think it differs from your real-world output loss.

Yes I encourage you to play around with PVWatts as it's the best predictor. My real world data won't apply directly to you because my azimuths are not due east, west or south, they're all somewhat off. While doing the research and design, I created a spreadsheet to calculate all kinds of things about the system including predicted production and ROI, and I fed in data from PVWatts and other sources. I've attached two pictures, one showing the orientation of my house and where I installed the panels, the other a screenshot from my spreadsheet showing the PVWatts calculations for my six different orientations.

House.PNG


PVWatts.PNG

My "just north of east" panels are supposed to put out ~80% of the power of my "just east of south" panels over the course of the year, and specifically in March they're supposed to put out ~78%. My real life month to data data that I posted earlier showed them putting out 78.5% so far in March, so pretty spot on. My friend with the (allegedly) due east and due south installation, was seeing 81% production month to date from his eastern panels, so I'd really expect it to be in that ballpark.

You might also notice some strange values in my PVWatts numbers, where it predicts my southern panels will actually make less energy than my eastern panels through most of the summer. I don't know if that's related to a predicted temperature delta and subsequent efficiency loss or what, but it sure doesn't make up for the winter months, where the southern panels put out almost double what my eastern panels will do...

[aleenoor]

For better cost effectiveness, go w/the south orientation, which will almos6t always give a greater annual output per installed Watt, use standard panels, and pick up the 20% area efficiency advantage via conservation measures.

As for "high efficiency", I'd keep in mind that is an area efficiency, not a production efficiency. For the most part, and usually within some few %, all equal (electrical) size arrays that use known, and decent quality components, including Sunpower and most any other quality mfg. product, will, in the same location, orientation and duty, produce about equal annual output for probably as long as you'll own a system. Snoop around PVOutput.org and compare outputs for similar orientations in your area for some corroboration on that.

Suit yourself, but if you have sufficient room, using "high efficiency" panels will increase system price by 20-25% per installed Watt, but probably won't get you much, if any, benefit beyond bragging rights. If saving money and reducing an electric bill are goals, and you're cramped for space, one alternative is to first pick up a 20% or so bill reduction via conservation and then supply the remaining desired bill reduction using fit for purpose standard panels.

Sunpower's good stuff, but so is a Mercedes. Panels are a commodity these days. A Ford and a Mercedes are equally good grocery haulers. Solar's an appliance, not a lifestyle. Pay your money, take your choice.

Take what you want of the above. Scrap the rest.

Hi JPM,
I will take it all. I agree with everything. I have done the interior efficiencies where possible i.e. Hybrid water heater, high efficiency AC/HP 18.5 SEER, upgrading my pool-pump etc. Its a big house and I have an EV. Looking to get another for wife soon. So I will very much use what I produce. Per my goals, 11.7kW (utility limit) with net-metering should account for 95 to 100% of my annual consumption. FYI, I do not have natural gas at home. This PV systems will represent essentially ALL of my household's energy/fuel demands. (except inter city travel).

That said, I am limited to South facing roof space. Limited to about 31 72c panels or 40 60c panels. I want to be able to produce as much as possible without crossing the 11,764W DC limit that my utility has. Beyond that I have to get $1M insurance because I am considered a Generation Plant. So essentially, I am optimizing against cost of equipment and maximum AC power I can generate within the 11.7KW DC ceiling.

Now If I am looking at about 60c/W for 300W 60 cell panels which mean I will be able to fit all panels facing south.
However, I can also get 325W 72 cell panels at 45c / W. But that will mean of the 4 strings, 1 will get pushed to West and produce only 85%.

==> Marc - I hope you don't mind me starting this tangent on your thread! Btw I called superior today and expecting a call back. Lets see.

[aleenoor]

Yes, that is who I was shopping against. I ended up buying from Tandem, below is their quote, with Renvu's price in yellow.


Quote.JPG

Congrats, those are good prices. Renvu has really good prices on Ironridge. Did you decide on the panels. How about Canadian 300 Mono. They should match the size of your current panels. I thought they are about 56c /W. Are you adding to your current setup ?

[ButchDeal]

That said, I am limited to South facing roof space. Limited to about 31 72c panels or 40 60c panels. I want to be able to produce as much as possible without crossing the 11,764W DC limit that my utility has. Beyond that I have to get $1M insurance because I am considered a Generation Plant. So essentially, I am optimizing against cost of equipment and maximum AC power I can generate within the 11.7KW DC ceiling.

Now If I am looking at about 60c/W for 300W 60 cell panels which mean I will be able to fit all panels facing south.
However, I can also get 325W 72 cell panels at 45c / W. But that will mean of the 4 strings, 1 will get pushed to West and produce only 85%.

so you can fit 168 more cells on the south roof by using 60cell modules. I would go with 295w canadian or pretty much anything over 280 watt 60 cell south facing.
at 295 X 40 = 11.8kw which is just over your limit or 290 X 40 - 11.6kw just under.
Have you looked into how much the liability insurance will cost above what is already on your homeowners policy? Mine already had it.


BTW: 325W 72 cell modules are just under 17% efficient which is equivalent to a 275W 60cell module.

[Magius]

I hope you don't mind me starting this tangent on your thread!

Heck my thread was all wrapped up a couple pages back. I got the information I needed from the very helpful folks here and was able to move forward on my install. If you want to use this space to ask more questions feel free.

P.S. - I was going to suggest the same as Bruce, find out what it would cost to up your liability coverage on your homeowners. I only have $300k on mine, and thankfully since I'm under OUC I'm exempt from the Tier II, $1M requirement. But it's possible you might find out it's only an extra $25-$50/year, in which case it's just a small setback in your ROI. Of course, if the 11.7kW system is going to cover 95-100% of your usage, there's really no sense in pushing for more...