Tesla Solar inverters

[brucet999]

It depends on if you hook them up on 2 sides of the AC of your house.,,,or on a single side.

In the case of 240V AC....you had better have a phenomenally balanced system if you plan on running a 240Volt appliance off grid with them. Unbalanced 240 volts can kill appliances.

For instance 100 volts AC on one side and 140 volts AC on the other side is indeed 240 Volts AC, however I wouldn't try and run and air conditioner unit on that. If you happen to have a window air conditioner unit.....it will vibrate your whole house.
The Push-Pull of AC in this situation will be like holding a 30 pound weight in one hand and a 5 pound weight in the other and spinning around as fast as you can.

This answer made no sense to me, so I looked up Enphase technical data sheet and found this:
Nominal (L-L) voltage/range2 240 V / 211-264 V 208 V / 183-229 V

Inputs to main panels in the US are never 120V.
All Enphase micro inverters output single phase nominal 240V or 208V.

 

[Garlan Garner]

This answer made no sense to me, so I looked up Enphase technical data sheet and found this:
Nominal (L-L) voltage/range2 240 V / 211-264 V 208 V / 183-229 V

Inputs to main panels in the US are never 120V.
All Enphase micro inverters output single phase nominal 240V or 208V.

All I know is that I ran off grid with Enphase a lit up a 120V 60W lightbulb 8 years ago.

Check their micro-inverter setup page. I see every one of their microinverters being able to be used in a 120V system. Look at the project voltages.

Microinverters - IQ 7, IQ 7+, IQ 7X, IQ 6, and IQ 6+ | Enphase

 

[Garlan Garner]

BTW....String Inverter fans.

Please don't go to Enphases' homepage and see the comparisons between micro-inverter and string-inverter setups.

String-Inverters vs. Micro-Inverters | Enphase

 

[nwdiver]

One such Luxury is per panel monitoring.

Another Luxury is varying string lengths.

Another Luxury is the ability to use whatever panel you want wherever you want. Mix and match Panels on the same string...

Not for the homeowner... 98% only care about how much it costs and how many kWh they'll get. It's rare that space is super limited AND they're willing to pay 10% more for 1% kWh...

 

[Garlan Garner]

Not for the homeowner... 98% only care about how much it costs and how many kWh they'll get. It's rare that space is super limited AND they're willing to pay 10% more for 1% kWh...

I'm a homeowner. and I use the luxuries EVERY DAY.

As a matter of fact...you can click on such luxury below in my homeowner signature. I've got about 9KW coming off my roof RIGHT NOW....and 2.1.5 is not doing as well as the rest. Why is that?

 

[nwdiver]

BTW....String Inverter fans.

Please don't go to Enphases' homepage and see the comparisons between micro-inverter and string-inverter setups.

String-Inverters vs. Micro-Inverters | Enphase

LOL; 100% false. Why would the other 3 panels be at 50%? If this was true all the panels in the string in the screenshot I posted would have been ~43w instead of ~66w. Shaded panels DO NOT bring down unshaded panels in one string. It's utter nonsense.

FICTION;

REALITY;

I'm a homeowner. and I use the luxuries EVERY DAY.

As a matter of fact...you can click on such luxury below in my homeowner signature. I've got about 9KW coming off my roof RIGHT NOW....and 2.1.5 is not doing as well as the rest. Why is that?

Yes; We're in the 2% interested in how the systems work... (some more concerned with how they ACTUALLY work than others... ) Most people don't care...

 

[Garlan Garner]

LOL; 100% false. Why would the other 3 panels be at 50%? If this was true all the panels in the string in the screenshot I posted would have been ~43w instead of ~66w. Shaded panels DO NOT bring down unshaded panels in one string. It's utter nonsense.

View attachment 316408

Now the argument is going where it should be. Argue your point with Enphase. Tell THEM their website is wrong... I agree with them in a non-bypass array....but don't argue with ME....its not MY website.

Tell them that its utter nonsense - not ME.

Let us know what they say....

 

[nwdiver]

Now the argument is going where it should be. Argue your point with Enphase. Tell THEM their website is wrong...

Tell them that its utter nonsense - not ME.

Let us know what they say....

Lots of fake-news out there... Enphase is the least of it... why are you promoting nonsense? Do you actually believe what Enphase is advertising? If so how do you explain the real-world data?

Simple Question: 1 String of 10 300w panels on 1 MPPT. Full Sun. The First cell group of the first panel is shaded. What is the power output of the string? The correct answer is ~2900w. NOT ~1500w.

 

[Garlan Garner]

Lots of fake-news out there... Enphase is the least of it... why are you promoting nonsense?

Nope....your argument isn't with me.

String-Inverters vs. Micro-Inverters | Enphase

Residential Solutions | SolarEdge at the Traditional Inverter section....they say the same thing.

TS4-R

Tigo Look at the bottom of their homepage concerning shading issues.

So..let's tally it up. Enphase is wrong. SolarEdge is wrong.... SMA ( String Inverter Company ) is wrong. Lets see....who else? Oh yeah...TIGO.

ENPH SEDG

You should stop all of these companies from publishing fake news.

 

[nwdiver]

Nope....your argument isn't with me.

My argument is with who ever is spreading nonsense... which on this thread is you. Explain how the Enphase graphic is correct. Explain the real world data.

I've explained how Enphase is incorrect... where am I wrong? Like I said previously... there's a misconception that if one panel in a string is 100w ALL panels in that string must also be 100w. Not true for the reasons I've given and backed by REAL WORLD data. Not some gimmick drummed up by a marketing stooge that probably doesn't know the difference between a volt an amp and a watt...

 

[Garlan Garner]

My argument is with who ever is spreading nonsense... which on this thread is you. Explain how the Enphase graphic is correct. Explain the real world data.

Nope......wrong answer. Contact all of those 4 companies I provided references to because THEY are all saying the same thing ( nonsense to you ) . Whats the common dominator here? Or moreso...the uncommon denominator .

Watch their videos and argue with them. Their videos explain more that what I can do with words.

 

[nwdiver]

Nope......wrong answer. Contact all of those 4 companies I provided references to because THEY are all saying the same thing. Whats the common dominator here? Or moreso...the uncommon denominator .

LOL; So that's your response? I don't know what I'm talking about talk to the marketing department that created the nonsense?

I've explained how Enphase is incorrect... where am I wrong? Like I said previously... there's a misconception that if one panel in a string is 100w ALL panels in that string must also be 100w. Not true for the reasons I've given and backed by REAL WORLD data. Not some gimmick drummed up by a marketing stooge that probably doesn't know the difference between a volt an amp and a watt...

TONS and TONS of nonsense out there... the point here is to have an intelligent discussion about what's right, what's wrong and why. If you're gonna post something have the balls to explain / defend it.

 

[Garlan Garner]

LOL; So that's your response? I don't know what I'm talking about talk to the marketing department that created the nonsense?

 

[nwdiver]

LOL

Simple question. Why would the other panels be at 50%? I'm honestly curious as to why you think this is true....

 

[wwhitney]

I think shading is a bit complicated.

Say you have an unshaded string of panels, and it is operating at I_mp (maximum power), and you start shading one single cell in one substring of one panel. With reduced irradiance, the cell's I_sc (short circuit) will be decreased. As soon as the cell's I_sc drops below the string's previous I_mp, the only way the cell can pass the full (previous) I_mp is for it to become reverse biased. At that point the substring's bypass diode should take the substring out of the string. Since I_mp is often pretty close to I_sc, it doesn't take much shading on a cell to cause this to happen.

The image nwdiver posted shows this, where each panel has 3 substrings. Each of the two reduced power panels has shading on just one substring and therefore produces 2/3 power.

Now to look at Enphase's diagram, the shaded area on the first panel is the bottom half. This area might be half of the substrings of the panel, in which case the panel would produce half power, but all the other panels in the string should produce full power. Or the area might intersect every substring of the panel, in which case the panel would produce no power, but again the other panels in the string should produce full power.

In the case of partial shading, the situation is more complicated. If some panels on the string have light shading, then the string I versus V curve may end up with two (or more) local power maxima. That is, rather than drop out the lightly shaded panels and maintain the previous I_mp, dropping the string current below the shaded panels' I_sc would allow the shaded panels to produce power, and that power may or may not make up for the reduced power generated by the unshaded panels in the string. So the actual details will depend on the MPPT algorithm the string inverter uses.

Cheers, Wayne

 

[nwdiver]

Now to look at Enphase's diagram, the shaded area on the first panel is the bottom half. This area might be half of the substrings of the panel, in which case the panel would produce half power, but all the other panels in the string should produce full power. Or the area might intersect every substring of the panel, in which case the panel would produce no power, but again the other panels in the string should produce full power.

In the case of partial shading, the situation is more complicated. If some panels on the string have light shading, then the string I versus V curve may end up with two (or more) local power maxima. That is, rather than drop out the lightly shaded panels and maintain the previous I_mp, dropping the string current below the shaded panels' I_sc would allow the shaded panels to produce power, and that power may or may not make up for the reduced power generated by the unshaded panels in the string. So the actual details will depend on the MPPT algorithm the string inverter uses.

Cheers, Wayne

Yep... it's that top bit that's complete nonsense. And the first panel would be at 0 if the bottom cells are shaded since it's blocking half of each group not one group so really everything about that graphic is wrong... and everyone here is now dumber for having seen it Nothing complicated there. I've seen this misconception repeated over and over and over. Unshaded panels are generally unaffected by shaded panels. The one major exception is parallel strings on a single MPPT. If you have 2 strings in parallel and one cell is shaded suddenly ALL panels are forced off their MPP but this DOES NOT happen if each string is on an independent MPPT which is becoming more common. All new SMA inverters <8kW have 2 or 3 MPPTs.

The complicated part of shading is 'soft' shading. If the bypass diodes are activated a panel under 'soft' shade could be removed from the string even if it could be generating ~50w with a micro or optimizer. Is that ~50w worth the expense of additional equipment to harvest?

More to the point... bypass diodes aren't an add-on. They're a REQUIREMENT. If the other panels were pulled down to 150w from 300w that energy would be going somewhere... probably into the shaded cells which means a fire, fires are bad. Bypass Diodes are a necessary safety feature on ALL UL panels.

 

[winfield100]

Show me the numbers... I'm a numbers guy

I want to believe you... but I gotta see the numbers...

This is why SMA is shifting to optimizers...

Also doesn't help that some people keep perpetuating the myth that string inverters can't handle shade...

Don't get me wrong... SolarEdge makes a fine product... but for 99% of systems the additional expense will NEVER be recovered.

I need to collect data from the 30kW SolarEdge owner and compare that to the 27kW String System I designed. Both systems are ground mounts 180S with no shade. The Data is coming from the actual utility production meter. I'm expecting the 27kW String system to slightly outperform the SolarEdge because the company that installed the SolarEdge system used a 20 degree tilt vs 30 and ran AC lines vs DC. Should be interesting.

.... there is a chance that I'll start using SolarEdge for systems <5kW due to NEC 2017... depends on how much the TS4-Fs cost...

Any update on the data collection of the 27 vs 30kW system with different inverters?

 

[winfield100]

Show me the numbers... I'm a numbers guy

I want to believe you... but I gotta see the numbers...

This is why SMA is shifting to optimizers...

Also doesn't help that some people keep perpetuating the myth that string inverters can't handle shade...

Don't get me wrong... SolarEdge makes a fine product... but for 99% of systems the additional expense will NEVER be recovered.

I need to collect data from the 30kW SolarEdge owner and compare that to the 27kW String System I designed. Both systems are ground mounts 180S with no shade. The Data is coming from the actual utility production meter. I'm expecting the 27kW String system to slightly outperform the SolarEdge because the company that installed the SolarEdge system used a 20 degree tilt vs 30 and ran AC lines vs DC. Should be interesting.

.... there is a chance that I'll start using SolarEdge for systems <5kW due to NEC 2017... depends on how much the TS4-Fs cost...

Any update on the data collection of the 27 vs 30kW system with different inverters?

 

[nwdiver]

Any update on the data collection of the 27 vs 30kW system with different inverters?

No... not yet... I'm out of state and only have remote monitoring of the 27kW...

 

[winfield100]

i have noticed a 9.9kW Kit w/Solaredge seems to run about $1.40/watt for panels, inverter and ?optimizers?
is an additional cost of $1.60 - $2.60/watt reasonable for installation?

Does that inverter work w/powerwalls and integrate into a VPP?

i'm at ~ Lat, 26.61, Lon: -81.94
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