AC-Coupled Grid Tie System

[ncsolarelectric]

No experience with Solar Edge, but for certain reasons I might use it in my next install.

Sunny Boy has adjustable voltage and frequency parameters. I've widened frequency of some UL-1741 operating behind Sunny Island to the limits of UL-1741-SA. Off-grid they support much wider voltage and frequency, intended to remain on-line if a generator is feeding in.

Your chosen brand may also allow some such adjustment.

"talk to SolarEdge" by a data bus?

SolArk and Skybox (plus its newer replacement) of course are LV HF hybrids that support AC coupling. At least to some extent, as we've been following the tribulations of people trying to use SolArk with 100% of PV AC coupled.

The need for shade mitigation is really only a thing if you have two or more PV strings connected in parallel, and shade will affect a significant percentage of panels in one string but not the other. If you can plan your shade wisely, then just parallel them. If you use an inverter with separate MPPT input per PV string (e.g. Sunny Boy -41), each is independently optimized.

Better read up on the failure rates of Solar Edge and its optimizers. I started one.

Solar Edge - an installer's blog

Came across the following blog. It includes the company's installed system numbers and failure rates for SolarEdge, Fronius, Enphase. Also, information on limitations and best use of optimizers. https://www.mcelectrical.com.au/solaredge-inverter-optimiser-review/

diysolarforum.com

We're reading of installers who stopped using them.


"best efficiency (>99% AC/DC)"?
That's not what matters anymore. Might have when PV was $5/watt.
Looks for best W/$ and reliability.

Since moving to NC, I've had to troubleshoot or replace three SolarEdge inverters.

 

[solar8484]

SolArk units have all kinds of bells and whistles, fancy interfaces, one-box-does-it-all, etc, but they are built cheaply and are High Frequency inverters that do not handle big in-rush currents well. The all time king of robustness and reliability are the SMA Sunny Island units. Seriously, there isn't anything that even comes close to their quality, but while they are strong in the reliability department, the user interface is a 2 line dot matrix display and you need to squint to read it.

Any idea why there is no Will Prowse review videos for SMA Sunny Island? For that matter, Magnasine, Victron, Outback as well. I would like to see how the "all time king of robustness" compares with the other inverters he has reviewed.

 

[Solar Canada]

Since moving to NC, I've had to troubleshoot or replace three SolarEdge inverters.

We have had issues with the Energy Hub version but the HD Wave has been bullet proof for us. I have had to replace 4 EH's this year alone. It is also an absolute nightmare to get the External CT's for Import/Export to read correctly, there are more issues with that than I can mention and their only response is that we have installed it incorrectly which has been disproven over and over. I have dealt with customer complaints all year with this issue which has nothing to do with PV Production, extremely frustrating and still ongoing.

 

[MurphyGuy]

Any idea why there is no Will Prowse review videos for SMA Sunny Island? For that matter, Magnasine, Victron, Outback as well. I would like to see how the "all time king of robustness" compares with the other inverters he has reviewed.

I think Mr. Prowse reviews mostly the cheaper Chinese lower quality units in an attempt to find out if any of them actually represent a decent value for what they cost.

Higher quality units like SMA, Victron, Outback, etc, fall into a different category in both quality and price. Will seems to stick with what I consider the "toys and hobby" stuff, and I think he does an excellent job going through their attributes.

Don't get me wrong, if you want to invest in a lower quality hobby system for camping, an RV, or other non-critical application, I think Will's video reviews are probably the place to go to study what's good and what's junk. But the real off-grid stuff that keeps your family secure and comfortable is on a different level and I don't think that's the purpose of his channel.

For that purpose, I would suggest visiting David Poz's channel as he tends to review some of the stuff aimed at being permanently off-grid.

Well, that's my take on it anyhow.. honestly, I haven't watched either of them for quite some time as I'm already set up.

 

[ncsolarelectric]

We have had issues with the Energy Hub version but the HD Wave has been bullet proof for us. I have had to replace 4 EH's this year alone. It is also an absolute nightmare to get the External CT's for Import/Export to read correctly, there are more issues with that than I can mention and their only response is that we have installed it incorrectly which has been disproven over and over. I have dealt with customer complaints all year with this issue which has nothing to do with PV Production, extremely frustrating and still ongoing.

All the failures I've seen were the HD wave 7.6kW model. There were three in 2 years. For grid-tied battery time-shifting, I'm using Hoymiles Microinverters and a battery current limiter board I designed to allow the battery to behave like a solar panel. I use this and a timer on my grid-tied battery charger to charge during the day and use the energy at night.

 

[Hedges]

Interesting.
Either HD wave has had good and bad batches, or site conditions sometimes kill it?
Has anyone ever determined what sort of failures?

 

[ncsolarelectric]

Interesting.
Either HD wave has had good and bad batches, or site conditions sometimes kill it?
Has anyone ever determined what sort of failures?

In two of the cases, the installation was not very clean. One had water inside the inverter box because the conduits were brought in the side and were loose. Another had ground fault issues at the array and a burnt DC home run. IMO, installing optimizers AND an inverter is double the labor and complexity of simply installing microinverters. If microinverters had been used, neither of these issues would've been possible.

 

[Solar Canada]

Faulty installations are definitely not good, extreme care needs to be taken with any of this equipment to ensure there are no failures or your starting out without a chance. Over the years we have seem some terrible work by company's that are now out of business thankfully, we have lasted and grown in large part to our reputation of clean and robust install work. Our team has installed MW's of PV including a 600kW Project for a large Utility Company in Ontario recently using SE Commercial Equipment and things have worked out great.

We are definitely bringing this gentlemen's discussion into a tangent here, signing out. Good luck in the future folks.

 

[solar8484]

I think Mr. Prowse reviews mostly the cheaper Chinese lower quality units in an attempt to find out if any of them actually represent a decent value for what they cost.

Higher quality units like SMA, Victron, Outback, etc, fall into a different category in both quality and price. Will seems to stick with what I consider the "toys and hobby" stuff, and I think he does an excellent job going through their attributes.

Don't get me wrong, if you want to invest in a lower quality hobby system for camping, an RV, or other non-critical application, I think Will's video reviews are probably the place to go to study what's good and what's junk. But the real off-grid stuff that keeps your family secure and comfortable is on a different level and I don't think that's the purpose of his channel.

For that purpose, I would suggest visiting David Poz's channel as he tends to review some of the stuff aimed at being permanently off-grid.

Well, that's my take on it anyhow.. honestly, I haven't watched either of them for quite some time as I'm already set up.

Lol, maybe Will is reading these posts ...

BTW, is SolArk really significantly cheaper than equivalent capacity higher quality brands? They seem pretty expensive.

 

[ncsolarelectric]

Does Will even evaluate grid-tied inverters, or only off-grid? I was surprised in one of his recent videos with the new EG4/Megarevo Inverter, and was wondering if he was going to operate it in export mode. Maybe he does read the forum.

 

[Hedges]

BTW, is SolArk will significantly cheaper than equivalent capacity higher quality brands? They seem pretty expensive.

Top brands aren't cheap.
SolArk is about all you need in one box, saves on parts as well as labor.

SolArk seems expensive (given familial relationship to cheaper brands)
May still be less expensive than systems from SMA, once you connect enough units of each brand to have comparable performance. And SolArk saves on bits and pieces to assemble them.

2x Sunny Island + 2x Sunny Boy is about 12kW PV to grid or load or battery, 12kW battery to loads. But 24kW PV + battery to loads. $15k?
Compare to 1x SolArk might be around 12kW or so in any direction. $8k?

Off grid, 2x Sunny Island + 4x Sunny Boy is 24kW PV to loads + battery, 36kW PV + battery to loads. $20k?
Compare to 2x SolArk for a bit less money. $16k?

SMA European models are a better fit for reasonable sized smaller systems, because one Sunny Island and one Sunny Boy is all it takes. Two Sunny Boy can also be supported, even on grid (double the voltage, double the watts can pass through relay.

I have a bunch of SMA because I picked up liquidation bargains. Balance of system has added up.