PO vs MI

[Supercharger619]

Which system (microinverter vs power optimizer) would use more wiring/cables, junction boxes, misc. equipment etc. leading to more money and time?

Ease of installment, from a DIY perspective?

[library]

They're pretty similar. Both have a box behind the panel. Cables down near your interconnect (Main Service Panel). You don't need conduit in the attic space for microinverters since it's standard 240V AC.

I wasn't thrilled with microinverters and the combining done on the roof. Additionally breakers are used at the combining box on the roof which seemed like a terrible idea to me (pop a breaker and it's a trip to the roof to reset it). With optimizers, or traditional strings, it's just a DC run down to the Inverter and while you can combine them separate strings are much easier (little more wire, that's all).

I installed my own Solaredge system. It was pretty easy, it's a lot of work no matter which system you do. Most of the work is installing the mounts on your roof, installing the panels and running the conduit. The electrical work is relatively easy on the ground and just hooking up wires. I think Solaredge has the best monitoring as well but freely admit to having done only an hour of research on Enphase and their monitoring portal.

[Supercharger619]

Out of curiosity did you have an online designer create a wiring diagram/plan for you?
You mentioned it was pretty easy (conceptually?) but a lot of work (manual labor)?
Did you have any help, any electrical/solar experience?

[library]

I used solardesigntool.com to build my permit package. It put everything in a professional permit package. I'm sure it made the city feel better. I also used Vector Engineering to certify my roof could handle the additional load. Permits and related fees were 9% of my total cost. More than I would have expected but unless you live in the sticks it always needs a permit.

I have construction experience including residential electrical. I'm also really good at researching online. I had a friend actually help with the panel install and I rented a towable boom lift to get the panels on my roof. I can't think of any possible way you could physically install the panels on a > 5/12 roof pitch by yourself. You'll definitely need a friend for that part.

Designing the system is easy with both optimizers or inverters. You don't have too much to worry about like a string system with string size and voltages. There *are* string limits for Solaredge but they're pretty generous and mostly you just want to be aware of 5000 watts max per string. Enphase has string limits too in that you can't exceed breaker ratings. I used ironridge racking and their site will draw stuff up for you. The Flashfoot2's are really good and I didn't have any trouble with the racking.

I might have used SolarEdge's design tool online just to double check but at that point I had the spec sheets memorized and my design matched theirs. My install was easy because I planned ahead and eliminated electrical issues. I had a 200A main service so I picked a system that fit within a 40 amp breaker (the max allowed on a 200A service). I had space in my main breaker panel for the solar backfeed breaker. If you need those things changed you should contact an electrician.

Just start drawing it all up. If you can't draw a wiring diagram of every component and every wire research it until you can or you give up and hire an electrician. There are online wire size calculators and all sorts of stuff to make this easy. SolarDesignTool has one built in. I particularly like the Soladeck flashed passthrough box, I worry about roof leaks a lot (you have one job roof, one job!)

Most DIY people have issues with the electrical, electrical is conceptually very simple it's just the large set of rules in the NEC that you need to learn. This forum has a wealth of knowledge available for googling. Additionally if you have a standard sort of setup SolarDesignTool did a really good job of drawing up my complete electrical diagram.

[Supercharger619]

Newbie question here but I was looking at a solar edge system and on their commercial 3-phase 66.6 kW inverter it is capped at 15,000 kW per string equally a total of 45,000 kW. I'm sure there's a way of getting it towards the max of 66.6kW do you have to run a string in series? THanks

[ButchDeal]

Newbie question here but I was looking at a solar edge system and on their commercial 3-phase 66.6 kW inverter it is capped at 15,000 kW per string equally a total of 45,000 kW.string. I'm sure there's a way of getting it towards the max of 66.6kW do you have to run a string in parallel? THanks

You run all the strings in parallel.

[library]

The models of inverters have different numbers of strings they can accept. Like an HD Wave SE7600 can take two strings but the SE3800 only takes one. But with a SE7600 you can't exceed 6000W on a string, you need the two strings to hit the inverter capacity. I don't know why you're looking at commercial systems though, this is really all you need to know.

http://www.solaredge.com/guide-designing-with-solaredge

and if you want more details (like say your commercial system) then this has the specs you need as well. https://www.solaredge.com/sites/defa..._sizing_na.pdf

If you want to get more advanced just download their site designer. The thing with residential solar is everyone has tried to make it extremely simple. The panels come with connectors that you simply can't connect wrong. Most companies have design tools that do any calculations for you, it's a golden age for DIY'ers!

[Supercharger619]

I'm looking for a 3 phase inverter to support a 50kW system for a business site solar install. I've looked a their spec sheets, that's where I got the 15,000 kW per string. I'll look at the site designer, thanks, I thought it was odd that it's rated for 66.6 but only 15kw per string so I know there must be a way to make it work. I'll keep digging thanks.

[bcroe]

I'm looking for a 3 phase inverter to support a 50kW system for a business site solar install. I've looked a their spec sheets, that's where I got the 15,000 kW per string. I'll look at the site designer, thanks, I thought it was odd that it's rated for 66.6 but only 15kw per string so I know there must be a way to make it work. I'll keep digging thanks.

The 3 phase configuration is the AC OUTPUT arrangement. It says nothing about DC strings at the input.
Bruce Roe

[Supercharger619]

I'm not following. I was looking for a 3 phase inverter and solaredge has a decent priced 66.6 kW that fits my budget. My understanding is that the three DC input strings are capped at 15,000 each (as seen in attachment) which equals 45kW while it's rated for 66.6kW.

[bcroe]

I'm not following. I was looking for a 3 phase inverter and solaredge has a decent priced 66.6 kW that fits my budget. My understanding is that the three DC input strings are capped at 15,000 each (as seen in attachment) which equals 45kW while it's rated for 66.6kW.

That string limit is in relation to the operation of the DC optimizers. You are not limited to 3 strings,
6 strings might be a good number. Bruce Roe

[Supercharger619]

So those multiple strings go to a combiner box, does the inverter see it as one large string?

[bcroe]

So those multiple strings go to a combiner box, does the inverter see it as one large string?

Strings, of the same operating voltage, get tied in parallel. My inverter can take 6 strings, but because of
distance, a remote combiner box is used. Research your situation to see what is best. Bruce Roe

[ButchDeal]

So those multiple strings go to a combiner box, does the inverter see it as one large string?

They are parallel strings with a combiner or just in the inverter. Download the installation manuals from SolarEdge. The 66.6 is a double 33.3kw inverter pair.
The strings do NOT have to be the same length and you can use the dual optimizers.

[Supercharger619]

Cool, thanks bcroe and Butch.

Just for my own understanding, a crude wiring flow diagram for a solaredge system would be;

Panels->Power Optimizers-> Junction box (if needed)-> +/- Combiner box->DC Disconnect->Inverter(s)->AC Disconnect (is this built in to the inverter?)->Circuit Box

For any of those with any solaredge experience is the energy meter (https://www.solaredge.com/us/product...-grade-meter#/) needed to determine production and usage? I thought that would be standard with the existing system. Any thoughts on whether it's worth adding to the system?

Dumb question but does conduit need to be secured to a flat roof? Trying to get away with no roof penetrations.

Thanks