PV design software

five.five-six

Senior Member
Location
california
I have decided to do a PV system, it will be on my home for the first one. I have been looking at PV design software and they range from free to ungodly expensive, neither of which is appealing to me. I’m looking for recommendations. If I decide PV is something I want to offer, it will be for residential and some commercial/industrial mostly servicing existing customers.
 
IMO, one doesnt really need PV software unless you are getting into PV in a big way and/or with big systems. For energy production, PV Watts is supposed to be quite accurate, and the only other thing it would be nice to have software for is optimizing DC/AC ratio, but you are kinda splitting hairs with that unless its a large system.


I played around with PVSyst as they offer a 30 day free trail. You could get the trial version to get a feel for DC/AC ratio vs energy loss in your area for different system types.
 

jaggedben

Senior Member
See what the manufacturer you're using offers. Solaredge and SMA both have tools that are plenty good enough for residential. Otherwise PVwatts.
 

five.five-six

Senior Member
Location
california
See what the manufacturer you're using offers. Solaredge and SMA both have tools that are plenty good enough for residential. Otherwise PVwatts.
I think what I am looking for is something to help me with making the single line diagram, calculating roof layout and production per the azimuth and angle, conductor sizing, that sort of thing. Like I said, this will be my first PV system.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
I think what I am looking for is something to help me with making the single line diagram, calculating roof layout and production per the azimuth and angle, conductor sizing, that sort of thing. Like I said, this will be my first PV system.
Helioscope supposedly does all that, but I found the interface to be clunky to the point of unusability. I use AutoCAD for layout and line drawings, and I do my wire sizing by hand. We use Aurora for general information but to produce good layouts we have found no viable substitute for boots on the roof site assessment measurements and photos. Sometimes Aurora gets things very wrong; I wouldn't totally depend on it.
 

five.five-six

Senior Member
Location
california
Helioscope supposedly does all that, but I found the interface to be clunky to the point of unusability. I use AutoCAD for layout and line drawings, and I do my wire sizing by hand. We use Aurora for general information but to produce good layouts we have found no viable substitute for boots on the roof site assessment measurements and photos. Sometimes Aurora gets things very wrong; I wouldn't totally depend on it.
Yea, I don’t think I would quote or order anything without using a tape measure first


I was looking at one app that prompted me to order a report from roofreports.com I got the report and it seemed accurate but then the first app I looked at says it’s limited to roof under 4000 sq ft. So that’s not something I want to get setup on.
 

Zee

Senior Member
Location
CA
Why not just submit the basic measurements to a PV design professional. For 300 bucks they will make you a beautiful set of drawings to take to the permitting office. SLD, site plan, layout, section, mounting hardware detail, spec sheets, wire calcs.
It will also contain the code references and info needed.
Whereas, Each time the permitting folks find something is missing you gotta go back and re design and re submit....time is money.

Although most will want YOU to know what size wire and production etc.....they will just draw it nicely (which is very valuable in its own right for permitting)

Sounds like you still need to learn the design basics. (e.g. calculations on determining performance, V and A limitations, conductor sizing, etc etc.......)
 

ron

Senior Member
Why not just submit the basic measurements to a PV design professional. For 300 bucks they will make you a beautiful set of drawings to take to the permitting office. SLD, site plan, layout, section, mounting hardware detail, spec sheets, wire calcs.
Wow, Engineering is pretty cheep in your area. Do they sign/seal the drawings too?
 

five.five-six

Senior Member
Location
california
Why not just submit the basic measurements to a PV design professional. For 300 bucks they will make you a beautiful set of drawings to take to the permitting office. SLD, site plan, layout, section, mounting hardware detail, spec sheets, wire calcs.
It will also contain the code references and info needed.
Whereas, Each time the permitting folks find something is missing you gotta go back and re design and re submit....time is money.

Although most will want YOU to know what size wire and production etc.....they will just draw it nicely (which is very valuable in its own right for permitting)

Sounds like you still need to learn the design basics. (e.g. calculations on determining performance, V and A limitations, conductor sizing, etc etc.......)

I have been talking to a few PV design professionals and $300 seems to be right in the ballpark. Some don’t do SLD, others outsource structural... really, I am thinking I need to budget in the area of $700 for engineering for a 3-10KVA residential system. Perhaps I just need to find the right PV designer.

I really don’t want to spend my time drawing things.
 

pv_n00b

Senior Member
Location
CA, USA
There is no software that is going to spit out an SLD that you can use to get a permit that I know of. The best I have seen will give you something that you can use to start from to make your own SLD after you do a little massaging. But for residential you really can get by very well with PVWatts for getting an idea of the energy production. NREL's SAM is a good free program if you need more horsepower.

The plan set companies can be great for getting inexpensive plan sets to get a permit. Do not confuse PV design services with engineering services though. Two completely different animals and while PV design is fairly inexpensive, engineering is not. That's one reason engineers almost never get involved in residential work outside of the occasional structural review. A residential project budget just can't pay for licensed engineering work. I've had contractors come to me with stories about how an AHJ is making them get an electrical PE stamp on their residential plans and there is just no money in the project for an engineer. I feel sorry for those in that situation.
 

BandGap1.1eV

Member
Location
East Coast
How do you select your modules? The variety available is overwhelming.

See whats available from your local supply house that specializes in PV. CED Greentech is a popular option. See whats in stock then do some homework based on those options. SunPower, LG, Qcells, seem to be safe residential options now-a-days.

As previously stated, producing an appropriate drawing set using virtual means is dicey. I've NEVER seen a respectable set come from the el-cheapo options online that outsouce to a drafter overseas. Find a designer/engineer at a local solar company and ask if he would do some work on the side, or perhaps the supply house could direct you to a local freelancer.
 

five.five-six

Senior Member
Location
california
See whats available from your local supply house that specializes in PV. CED Greentech is a popular option. See whats in stock then do some homework based on those options. SunPower, LG, Qcells, seem to be safe residential options now-a-days.

As previously stated, producing an appropriate drawing set using virtual means is dicey. I've NEVER seen a respectable set come from the el-cheapo options online that outsouce to a drafter overseas. Find a designer/engineer at a local solar company and ask if he would do some work on the side, or perhaps the supply house could direct you to a local freelancer.
I found this outfit, they don't seem el-chepo but they do seem reasonable. Their office is inside my territory.

https://yoursolarplans.com/services/
 

tallgirl

Senior Member
The top-tier modules (SunPower, Panasonic, Canadian Solar — depending on what you consider “top tier”) are all going to have 25-30+ year service lives and warrantees. You should pick based on price, availability, and if they face the street, appearance. I’m trying to get a local installer to do my new-to-me house and they prefer front-contact (“wires where you can see them”) panels because they are cheaper. I hate them and I like my house.

As for design — DO NOT let software, or an idiot, design any layout that can be seen by anyone who can make your life miserable. I worked for a manufacturer who gave us an “employee discount” and the installers they partnered with designed some of the ugliest arrays I’ve ever seen. If you can use microinverters or DC optimizers, do that. But also, don’t be hesitant to add a module or two (if you’re using panel-level electronics) if it balances the appearance of the array. Dittos for moving a stack over a ridge if you’ve got a stack that’s making your array look ugly. Design the layout by hand, then feed it to software.

I know this isn’t “electrical”, but I’m tired of ugly solar and the stuff is as cheap as can be these days — I paid $1,000 for 175 watt modules 12 years ago and 300+ watt modules are less than 1/4th that price today.
 

five.five-six

Senior Member
Location
california
So, I did find a local outfit who produced a submittal package for me for $250

I looks very good and I expect it will sail through plancheck.

The. Only thing is that I had given them drawings with 3 strings of 9 modules for a total of 27

the drawings they returned had 1 string of 14 and another string of 13.

They said that SolarEdge will work wit different sized strings.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
So, I did find a local outfit who produced a submittal package for me for $250

I looks very good and I expect it will sail through plancheck.

The. Only thing is that I had given them drawings with 3 strings of 9 modules for a total of 27

the drawings they returned had 1 string of 14 and another string of 13.

They said that SolarEdge will work wit different sized strings.
They are correct, and most SolarEdge inverters do not have fused inputs. If you have three strings, many AHJ's will insist that you fuse them, even though Solar Edge says it isn't required. They did you a favor.
 

Designer69

Senior Member
So, I did find a local outfit who produced a submittal package for me for $250

I looks very good and I expect it will sail through plancheck.

The. Only thing is that I had given them drawings with 3 strings of 9 modules for a total of 27

the drawings they returned had 1 string of 14 and another string of 13.

They said that SolarEdge will work wit different sized strings.

Were these stamped drawings for $250?

my god if PE's are stamping drawings for 250 bucks I don't want to live in this country anymore
 

pv_n00b

Senior Member
Location
CA, USA
Were these stamped drawings for $250?

my god if PE's are stamping drawings for 250 bucks I don't want to live in this country anymore
Plenty of PEs out there who are running stamp shops. A contractor once told me of a PE up in Napa who was retired who would stamp his plans for a few bottles of good wine. Very hard to find and prosecute stamp shops too.
 

Zee

Senior Member
Location
CA
Wow, Engineering is pretty cheep in your area. Do they sign/seal the drawings too?
Oh, I am not talking about engineering or stamps.

$300 for a DRAWING. By a drafter.....an Autocad jockey or architect is sufficient.

Their job isn't to know what the contractor or engineer needs to calculate or to know much about design and calcs, just to organize it pretty like.

We only need an engineer if tilted rack (wind loads), sub standard roof framing or custom racking.
 
KISS solution

KISS solution

Single line diagram: A single line diagram is not a complex thing. I made some objects in MS Powerpoint PPT (panel, array, conductors, combiner) and I just copy and paste for the systems that I have designed.

Drawing panel layout: I capture an image from Google Earth (GE) and use the measurement tool in that app to get the roof dimensions. I create a panel of the appropriate size (you need a little trig here because the roof rake) and copy and paste. I scale it to 1/100 (e.g., a 40" panel in landscape is 0.4"; the other dimension on a 6 and 12 roof is 60" in plan view (0.6" in PPT) for a 67" panel, in Excel the calc is: Plan Dimension =Panel Length*cos(atan2(12,6)); for a 3 and 12 roof, Plan Dimension =Panel Length*cos(atan2(12,3)) ). Use the Align and Distribute tools in PPT to neaten up the drawing after the approximate layout is complete. Panel gets pasted on top of GE image.

Designing panel layout: National Renewable Energy Lab (NREL) has tools that allow you to compute power at various latitudes and array orientation. Then you have to consider the potential for shade and the use of string versus microinverters. For example, I have one string where a few panels have reduced output at times due to shading from a chimney, and another string with late afternoon shading, on a few panels, from a tree. I went with microinverters to eliminate and overall 10 - 20% reduction on those strings that would have resulted if I went with string inverters. I also like the microinverters because of the safety factor, ease of design and panel level monitoring.
 
Top