Flat roof installation in Netherlands - considering glass-glass, bifacial, manufacturer, dimensions

[SeaGal]

Then we're fellow IET members. We should be more respectful of each other.

OK, it seems we're singing from different datasheets.

Then, it looks like there are multiple specs of SE inverter datasheets out there.

Ultimately, I'd only like to get to the point where I know 1) whether to get SolarEdge Home Hub or Enphase microinverters

Personally I'm not a fan of Enphase for the reasons mention in post #2, as well as being tied into their eco-system / data collection.. Also battery storage is more €€€ and less efficient, but YMMV.

Do consider other inverters like Sunsynk and the ones @Hedges mentioned.

 

[NeoX]

You keep referring to SolarEdge. Manufacturers control most of the narrative potential consumers get to see by creating it, and sometimes get heavy-handed trying to control what information is available from other sources (which should be a big red flag.)

I encountered and others reported experiencing or learning of various issues. Read through this thread, make sure you're confident in the quality of what you select.

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

I read the entire topic, the entire blog, and many of the recent comments. And compounded with my existing doubts about SolarEdge (I was aware of failure rates, but assumed they'd be on top of it by now; the negative sentiment around the value of optimisers in this forum; having to think about oversizing), I'm now more in the Enphase camp.

What's concerns me also about SolarEdge is their ropey website (which indicates their approach to software might also be lacking), difficulty to find information, the fact they outsource all manufacturing, and their restrictions on monitoring and alerts. I'm a data junkie, which I rely on for automation and efficiency, and this would upset me if I knew the installer had control of my alerts, and I have no control over their diligence or proactiveness.

I also dislike that they opted out of the SunSpec Alliance. Open interoperability for such a longterm investment is critical for me.

I also note that the recent comments on the blog indicate problems even in the past 12-18 months. This is too recent for me. As a tech person, I know that hardware, firmware, and software maturity takes time, and it won't suddenly go from being diabolical to great in the last 12 months of a 17-year tenure. They clearly need some major investment in their tech. For now, if I were to trade on them, I'd go short!

So, thanks for sharing this. It's what I needed to lean me away from the narrative being peddled by my supplier with his SolarEdge "guy on the inside".

I haven't been offered Fronius by any supplier, but it seems they have a presence in the Netherlands. However, I'd really like per-panel monitoring which means an MLPE system like Enphase is the way to go (I also haven't been offered any other microinverter system besides Enphase).

Personally I'm not a fan of Enphase for the reasons mention in post #2, as well as being tied into their eco-system / data collection.. Also battery storage is more €€€ and less efficient, but YMMV.

I just reread your point (e) in post #2, and I've since learned big panels at not really an option anyway in the Netherlands due to weight and availability for residential roof installations. So, I'm looking at around 440 Wp max. But from a price comparison perspective, as I mentioned in an earlier post, the price difference is about 3.3% more for Enphase in the best case, up to 18% worst case (depending on supplier; keeping things like panel model and number of panels the same). So, it's not really a huge margin if I get a good deal which shopping around seems to have afforded me.

 

[Hedges]

I think Enphase ecosystem could work well, assuming its performance meets your needs (I haven't looked into surge, etc.) But you are locked into their ecosystem (expensive batteries, with inverter bundled with storage capacity).

I'm using all SMA equipment. (lithium) Batteries have to be on the approved list or otherwise have supported communications. At 48V for Sunny Island, REC BMS is a popular way to DIY. For high voltage battery of Sunny Boy Storage and Smart Energy, don't know about DIY solutions. The batteries are available from BYD among others. Price per kWh seems to be about 2x the server racks we see; quality should be premium.

Surge capability of the SMA HV inverters is pretty anemic, hardly anything above continuous rating. Their LV Sunny Island is highly regarded and has about 2x surge. Not a cheap system (except for those of us in the US who got liquidation prices due to a customer bankruptcy.) Some of us use lead-acid with it, no lithium or BMS issues, only the traditional ones.

In the US, 48V HF SolArk seems to meet people's needs well. The related Deye and other brands are likely available to you at a fraction of the cost, but can't say if they have the software quality or steller support.

 

[NeoX]

I think Enphase ecosystem could work well, assuming its performance meets your needs (I haven't looked into surge, etc.) But you are locked into their ecosystem (expensive batteries, with inverter bundled with storage capacity).

I'm using all SMA equipment. (lithium) Batteries have to be on the approved list or otherwise have supported communications. At 48V for Sunny Island, REC BMS is a popular way to DIY. For high voltage battery of Sunny Boy Storage and Smart Energy, don't know about DIY solutions. The batteries are available from BYD among others. Price per kWh seems to be about 2x the server racks we see; quality should be premium.

Surge capability of the SMA HV inverters is pretty anemic, hardly anything above continuous rating. Their LV Sunny Island is highly regarded and has about 2x surge. Not a cheap system (except for those of us in the US who got liquidation prices due to a customer bankruptcy.) Some of us use lead-acid with it, no lithium or BMS issues, only the traditional ones.

In the US, 48V HF SolArk seems to meet people's needs well. The related Deye and other brands are likely available to you at a fraction of the cost, but can't say if they have the software quality or steller support.

Yes, I looked at SMA after your earlier message (sorry, I forgot to reply specifically as the topic had taken an unusual turn at that point), and I note one of my suppliers (out of 18) did offer the Sunny Tripower 5.0 together with SunPower Maxeon 3 panels which are uber expensive. But it doesn't offer the per-panel monitoring I would like. So, while it might be great and optimal solution at face value, for me I prefer more high-tech data-driven solutions, which is just a personal choice. So, Enphase is probably more suitable for me. My only concern is the 5-year warranty on some of the system components (IQ Gateway, IQ Relay, IQ Combiner), but that's just a risk I'll have to take. The components that sit on the roof have 25-year guarantees, and I can probably replace any of these components myself once they're all installed if it's just a matter of "unplugging the old one, and plugging in a new one."

I also like being within an ecosystem. I find a lot of advantages to this in terms of interoperability, and I'm willing to pay a premium for that. I do the same with insurance (keep insurances with one company), my technology (be it Microsoft, Azure, Google, Android, Samsung, etc.). But Enphase being part of SunSpec Alliance means they may have to maintain some amount of interoperability with other manufacturers (say, of batteries) in years to come. I don't know much about this - it's just my limited perception - but happy to hear more informed opinions on the matter.

 

[Hedges]

Warranty - Tripower 5 year, data sheet says extends to 10 year if registered.
That is same as their LF battery inverter Sunny Island. The HF grid-tie inverters Sunny Boy offered 20 year, of course are only powered half the time.
The single phase Sunny Boy Smart Energy, which is a hybrid both PV and battery, offers optional 20 year.

Panel monitoring - that will tell you if there are shadows on the panel, or if a bypass diode failed. If PV cells are going bad, that should also show up. If there is a few percent variation between panels, you would see that. Quality panels shouldn't fail, do degrade very slowly over time. Some panels have had major problems.

In the US, we are now required to have Rapid Shut Down, dropping entire array to < 80V. For fireman safety, but of course means string inverters don't have as big a cost advantage over microinverters. Companies like Tigo make modules for just shutdown, or for optimizer & shutdown & monitoring. SMA offers some, and many support SunSpec compatible modules. They had some incompatibility with Tigo. But maybe only supported in US, don't see mention on the European inverter data sheets.

Tigo, which makes the MLPE boxes, offers those and inverter systems for Europe.

EI Residential Solution (EU)

The Tigo EI (Energy Intelligence) Residential Solution for Europe includes the EI Inverter, EI Battery, EI Link, and Tigo optimizers, all brought together by the Tigo Energy Intelligence software platform to enable fast, flexible, and dependable installations.

www.tigoenergy.com

Energy Intelligence Solar Monitoring | Tigo Energy

Lower your solar PV O&M costs with Tigo Energy Intelligence platform, a PV monitoring software that enables visibility to PV module performance. Learn more.

www.tigoenergy.com

Monitoring [Rapid Shutdown [Optimization]]


I wouldn't count on Enphase interoperating with other brand equipment, especially batteries, because it is a proprietary implementation.
There is probably standardized communication for grid support, variation of power delivery and maybe reactive power they would do.

MLPE replacement: Unplug old, plug in new, register it in system to get data which may require you to have installer access. A few people here have done that.

I don't have experience with any of these devices except for older model SMA. Next year I will be installing one of their recently obsoleted Sunny Boy -41 and their not yet available Sunny Boy Smart Energy, together with Tigo RSD.

I have no MLPE, but do have multiple identical PV strings. Parallel into one MPPT so no per-string monitoring. I used clamp ammeter to identify an outlier, then had to unplug modules and test individually to find bad ones. One brand (of three), 5 modules after 18 years. But I wouldn't know of others unless it showed up at inverter or string level.

 

[NeoX]

Update. I pulled the trigger on this, and went for Enphase with 22 Hyundai HiT-H440MF-FB panels (HJT technology).

The supplier has suggested the Enphase IQ8AC. I questioned why not the IQ8HC given that the Enphase microinverters are generally underpowered for most high-Wp panels, but the response was that the IQ8AC is sufficient because my panels will be in an east-west configuration, not directly facing south. Otherwise, he'd choose the IQ8HC. Is this a fair assessment?

The chosen panel is not listed on the Enphase compatibility calculator, but if I choose a panel with similar Wp such as the Jinko JKM440N-54HL4R-B, it recommends all models of Enphase IQ8 microinverters - see attached.

So, this doesn't really seem definitive. How does one choose the best microinverter power for the panel?

 

[SeaGal]

The supplier has suggested the Enphase IQ8AC. I questioned why not the IQ8HC given that the Enphase microinverters are generally underpowered for most high-Wp panels, but the response was that the IQ8AC is sufficient because my panels will be in an east-west configuration, not directly facing south. Otherwise, he'd choose the IQ8HC. Is this a fair assessment?

Me again.... IMHO ( if you want it ), I'd go for the HC. That provides 380W vs 360W for only a price increase of a few € more per inverter.

I also have E-W facing panel and obviously overall, you get less peak power than a S facing array (but you get it over a longer time period).

BUT, the key point is that at mid AM and mid PM the sun is _directly_ perpendicular (*) to the E or W facing panels (i.e. half your panels are the same as S facing ones at that particular time), so I'd want to get the max from those panels at that time. In other words, IMHO, the supplier's logic is flawed.

You're already limiting each panel's output by using the micro-inverter, so I'd want to get the max you can from them

(*) edited to add, not sure "directly" adds any detail to the word 'perpendicular', but you know what I mean!

 

[NeoX]

Thanks, @SeaGal, and this was my thought also regarding the sun's position at different times. In my case, I will have southeast-facing panels and northwest-facing panels. Therefore, the southeast ones will definitely get direct sun in the morning. I've just emailed the supplier about this.

That said, given that the Enphase compatibility calculator seems to nearly always recommend all its IQ8 models for all modern panels, given that nearly all people will have some panels in their layout getting direct sun at some point in the day, why would anyone go for anything less than IQ8HC?

In fact, thinking about it, in my situation, would it perhaps be efficient to get the IQ8HC microinverters for the southeast-facing panels and the IQ8AC (or less) for the northwest-facing panels?

 

[SeaGal]

Thanks, @SeaGal, and this was my thought also regarding the sun's position at different times. In my case, I will have southeast-facing panels and northwest-facing panels. Therefore, the southeast ones will definitely get direct sun in the morning. I've just emailed the supplier about this.

That said, given that the Enphase compatibility calculator seems to nearly always recommend all its IQ8 models for all modern panels, given that nearly all people will have some panels in their layout getting direct sun at some point in the day, why would anyone go for anything less than IQ8HC?

Save a few € maybe? Or they have panels < 360W output. Why buy cheap cheese when nice tasting cheese doesn't cost much more?

In fact, thinking about it, in my situation, would it perhaps be efficient to get the IQ8HC microinverters for the southeast-facing panels and the IQ8AC (or less) for the northwest-facing panels?

How much does it save? I'd go for all the same myself. I suspect that your NW panels will still generate 85-90% of their output in summer afternoons, if only 20 degrees off optimum. So, if they're 440W panels, that's about 375W = still better to use HC.

YMMV, so guess you need to plug the numbers in, but are they much cheaper? Prices I saw were only 4% less expensive.

 

[NeoX]

I had a reply. It will be €10 more per microinverter for IQ8HC. So, €220 extra on a total cost of €12,535. But here's what he said (paraphrased). He said that the peak power of solar panels is not achieved at all in an east-west orientation, and it will reach a maximum of 70%. So, 440W x 70% = 308W. So, the IQ8AC with 366W is more than enough.

However, as soon as my panel performs above 83%, the IQ8AC would be underpowered. So, how accurate is his statement given that I will have southeast-facing panels at 13° tilt?

That said, I just tried the official Enphase system builder, and it recommends IQ8AC, and it doesn't even ask for the orientation. See attached bill of materials it generated for 22 440 Wp panels on a 3-phase grid.

 

[Hedges]

I think SOUTHeast could make a huge difference; you're near the frozen North.
Just pay the 220 bucks (or whatever you call them.) It could support larger replacement panels in the future. Or maybe my favorite, parallel strings (panels in your case) of different orientation.

Any data on differences in reliability? (not that we have access to the info we want.)

Then keep your eye out for deals on Enphase battery systems.

We in the US (California in particular) today have been snapping up pallets of NE Solar-370W Mono PERC Half-Cell modules, for $0.17/W (delivery included.) Buy when the price is right, not when you need it.

​

 

[SeaGal]

I had a reply. It will be €10 more per microinverter for IQ8HC. So, €220 extra on a total cost of €12,535. But here's what he said (paraphrased). He said that the peak power of solar panels is not achieved at all in an east-west orientation, and it will reach a maximum of 70%. So, 440W x 70% = 308W. So, the IQ8AC with 366W is more than enough.

However, as soon as my panel performs above 83%, the IQ8AC would be underpowered. So, how accurate is his statement given that I will have southeast-facing panels at 13° tilt?

He is 100% incorrect. I actually find it quite shocking he is claiming that.

And I am saying all this from real-life experience of 2 UK summers, with monitoring of power every 5s

As I said before..

I also have E-W facing panel and obviously overall, you get less peak power than a S facing array (but you get it over a longer time period).

BUT, the key point is that at mid AM and mid PM the sun is _directly_ perpendicular (*) to the E or W facing panels (i.e. half your panels are the same as S facing ones at that particular time), so I'd want to get the max from those panels at that time. In other words, IMHO, the supplier's logic is flawed.

I have 6.6kWp of E-W panels at just 15 degree tilt. Peak output hit 6kW (so just 10% less), though 5 to 5kW was more common (so a total reduction of around 15%-20%) - but that is middle of the day when the panels are 90 degrees out of alignment laterally.

The key point is that any production output (whether my 10-20% measure or his claimed 30%) reduction is of all the panels together, not individual ones that a micro-inverter is controlling. Mid am and mid pm, the panels facing the sun are operating close to their max kWp output. With micro-inverters it is the power for those individual panels you will want to maximise. I can guarantee that in summer, am and pm, you will be maxing out at 380W with the HC if you have 440W panels.

To me it is a no-brainer. What is €220 extra on €12,000+ ?

On a completely separate note...
I have no experience with 3 phase systems, especially micro-inverter based ones. But, with my electronic engineering hat on, would it not be best to have roughly equal power generated down all 3 phases, so that neutral current is minimised If so, then rather than 11 panels E and 11 panels W-facing, shouldn't you have 9 or 12 panels in each direction and the phases equally split between them? Might be worth doing some research on that - though I wouldn't take the salesman's word for anything technical!

 

[NeoX]

Any data on differences in reliability?

No, but this is an interesting point. Higher-rated electronics is going to last a lot longer than lower-rated electronics operating at the same power level. That's just common sense!

He is 100% incorrect. I actually find it quite shocking he is claiming that.

And I am saying all this from real-life experience of 2 UK summers, with monitoring of power every 5s

As I said before..

I have 6.6kWp of E-W panels at just 15 degree tilt. Peak output hit 6kW (so just 10% less), though 5 to 5kW was more common (so a total reduction of around 15%-20%) - but that is middle of the day when the panels are 90 degrees out of alignment laterally.

The key point is that any production output (whether my 10-20% measure or his claimed 30%) reduction is of all the panels together, not individual ones that a micro-inverter is controlling. Mid am and mid pm, the panels facing the sun are operating close to their max kWp output. With micro-inverters it is the power for those individual panels you will want to maximise. I can guarantee that in summer, am and pm, you will be maxing out at 380W with the HC if you have 440W panels.

To me it is a no-brainer. What is €220 extra on €12,000+ ?

I agree. But this still doesn't answer why Enphase themselves think IQ8AC is appropriate, and that was without specifying the east-west layout or tilt. Enphase recommends IQ8AC for 22 panels (I guess) assuming optimal conditions.

I have no experience with 3 phase systems, especially micro-inverter based ones. But, with my electronic engineering hat on, would it not be best to have roughly equal power generated down all 3 phases, so that neutral current is minimised If so, then rather than 11 panels E and 11 panels W-facing, shouldn't you have 9 or 12 panels in each direction and the phases equally split between them? Might be worth doing some research on that - though I wouldn't take the salesman's word for anything technical!

I did some research - ChatGPT. This was its response:

Given the equal number of panels facing northwest and southeast (11 each), a more balanced distribution of phases in a 3-phase system would be to stagger the connection of panels to each phase. Here's one possible approach:

1. Even Staggering: Connect panels alternately to the three phases. For example, connect the first panel facing northwest to phase 1, the second panel facing southeast to phase 2, the third panel facing northwest to phase 3, and so on. Continue this pattern until all panels are connected.

This even staggering helps distribute the load more evenly across the three phases, minimizing the potential for phase imbalances and reducing neutral current.

It's important to note that this is just one suggestion, and the optimal distribution may depend on the specifics of your system, including the capacity of your solar inverters and other electrical characteristics. If possible, consult with a qualified electrician or solar system designer who can analyze your specific situation and provide precise recommendations based on your system's specifications and local regulations.

In my situation, 9 panels each way would result in 18 panels instead of 22 panels which means I would generate less power. 12 panels each way would result in 24 panels which would not fit on my roof. 11 panels each way (22 total) make the best use of my roof space.

 

[SeaGal]

But this still doesn't answer why Enphase themselves think IQ8AC is appropriate

Puzzling. Let us know if you find out a valid technical reason for that with your intended 440W panels.

 

[SeaGal]

Hi... any progress? Just stumbled on this vaguely-related thread - thought it may be of interest to you...

Am I being bamboozled?

Good afternoon! So I recently had solar installed on my roof, but my performance thus far has been below advertised. My specs are below (please let me know if I should post something else). Also realize this is a DIY forum, so if I should go find somewhere else on the internet, fair enough...

diysolarforum.com

 

[NeoX]

Just by way of an update, I contacted Enphase to ask questions around their compatibility calculator, and they responded.

This is what I asked them:

I am about to purchase a solar system with 22x 440 Wp panels and Enphase microinverters. I have some questions:

1. Your system builder suggests the IQ8AC model which has a peak power of 366 VA. This assumes the panels will operate at max 83%. Why would it not suggest the IQ8HC which has a peak power of 384 VA? This would then support my panels operating at up to 87% which could be possible on sunny days.
2. Is there an advantage in getting a higher power microinverter in terms of strain on the unit? In other words, is it better for a microinverter to operate further below its maximum than closer to its maximum in terms of heat and reliability, as might be the case if I have an IQ8HC instead of an IQ8AC?
3. Is there such thing as a microinverter being too overpowered for the panels? In other words, would there be a technical problem if I get a microinverter with a peak power that is too high for the panel its connected to?

This was their reply:

1. We request you to please check if the panel module is compatible with IQ8HC microinverter at https://enphase.com/nl-nl/installers/microinverters/calculator
2. If the IQ8C microinverter is compatible per above link, there will be no issues regarding strain on the unit.
3. There will be no technical problem if the panel is compatible with the IQ8HC microinverter. If it's not compatible then it will stop producing when the input DC values go beyond the microinverter range.

I checked the compatibility, and the panel I'm getting is compatible with all IQ8 models (see attached).

I've already requested the supplier to provide IQ8HC microinverters instead of IQ8AC, so I guess everything's primed and ready to go now!

 

[frasere2]

Why limit your 440w panels to 380w (max continuous output of the microinverter)? You limit your system to 8.3kw. Optimizers plus a string inverter will max out your power at 9.68kw, plus be much cheaper. I think the IQ8HC is around $240, so $5324. You can get 22 optimizers for about $1000, and a 10kw inverter for about $1300, total $2300. So, you lose 14% power using the microinverters and it costs you an extra $3000.

 

[Hedges]

I favor string inverters, and they were very cost effective before RSD.
But I don't think a 10kW inverter for $1300 can be compared to Enphase microinverters, likely a difference in quality and longevity.
Compare SMA, Fronius, etc. to Enphase.

 

[OffGridForGood]

and they were very cost effective before RSD.

Can RSD be "DIY-able" using two-pole DC relays (one within a foot of the array perimeter on the string output, and another right beside the Inverter PV input) power the two relays on a single circuit to a big red button marked "RSD" and avoid all the high priced RSD micro-inverter stuff? No? Why not?

 

[Hedges]

It was for the previous incarnation, just something like < 30V outside the array. Simply a mechanical switch with extension handle worked. or mount inverter at array.

The new one also says < 80V between all wires including within array, so need to disconnect ever panel (or every other panel) from the rest.