Solar Edge [from: help me design the most efficient system]

SolarEdgeSolarEdge Registered Users Posts: 9
[note from Moderator]:

This thread has been split off to its own regarding questions about SolarEdge originally posted by:

heynow999 wrote: »
...So the idea is to get the absolute most production out of a 10kw system. We a flat roof with due south orientation and no shade. So what different ways are there to achieve this? What is the best direction and inclination of the panels? (43 deg N) We get a lot of clouds here, are there panels that perform better in cloudy weather? Would we be better to just use Sanyo's (+10,-0)? What about inverters? I have heard about a company called "Solaredge" that claims a 97% efficiency.

I am sure there are many things that I have not touched on

Thanks

Peter

The balance is the discussion about Solar Edge:

-Bill "Moderator" B.

=============================================I am a Marketing Associate at SolarEdge Technologies.
As you accurately heard, we provide a high efficiency power harvesting system. I would like to briefly explain how our system maximizes power production from your PV installation. Our solution is based on the SolarEdge PowerBox which tracks Maximum Power Point (MPP) at the module-level, a highly reliable centralized DC-AC inverter and a module-level and system-level monitoring portal.
These three components combine to allow higher efficiency under the following conditions:
• Unavoidable mismatch of modules due to accumulation of ice, dust, falling leaves, bird droppings, or inherent tolerance, and partial shading of one row of panels on the next row. As MPP tracking is performed for each module individually, performance of one module does not affect all other modules. In addition, module-level monitoring enables real-time identification and repair of poorly-performing modules.
Dynamic changes in irradiance due to fast moving clouds, causing standard inverters to track MPP slower. MPP tracking per one module is much faster than tracking for a whole string.
A wide temperature range in Ontario, causing standard inverters to track out of their sweet-spot due to the wide range of input voltages. Since SolarEdge's inverter is working on a fixed string voltage, it always works at its ideal voltage for maximum efficiency inversion.

Our system allows easy and safe design, installation, maintenance and upgrade of PV systems, at an inverter cost. One of our expert engineers would be happy to assist you in designing the most efficient system you are looking for.
For further information please visit our website http://www.solaredge.com/groups/technology/value-proposition/system-owners or contact me directly.
All the best,
Danya Golan, SolarEdge
«1

Comments

  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    Re: Help me design the most efficient system

    Nice marketing hype ... You can read our threads on the Enphase

    You can't change the way panels work ... temperature changes so does the vmp, same for shading.

    A Xantrex or SMA central inverter with a single string will outperform your system, perfect tracking ( exacty why is single panel tracking any different ? ), better efficiency, lower cost and decade of proven performance.

    With panels sizes today, you can do about 6kw in a single string. So for cost, performance, harvest and free monitoring, the Xantrex or SMA central inverters.
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help me design the most efficient system
    SolarEdge wrote: »
    I am a Marketing Associate at SolarEdge Technologies.
    As you accurately heard, we provide a high efficiency power harvesting system. I would like to briefly explain how our system maximizes power production from your PV installation. Our solution is based on the SolarEdge PowerBox which tracks Maximum Power Point (MPP) at the module-level, a highly reliable centralized DC-AC inverter and a module-level and system-level monitoring portal.
    These three components combine to allow higher efficiency under the following conditions: .....
    Danya Golan, SolarEdge

    Well, so how does your system work, with one panel in a string, shaded, and only producing 50W vs 200w like the others in the string?
    At the very least, the entire string would have to degrade by 150W.

    And "highly reliable" - is your module 20x more reliable than a central inverter ?
    (an average install being 20 or so panels). Got any data to convince
    a EE in the spacecraft industry? I know how MTBF stats are gamed.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Dave AngeliniDave Angelini Solar Expert Posts: 6,148 ✭✭✭✭✭
    Re: Help me design the most efficient system

    Mike,
    It probably is similar to the way National Semiconductor's "smart" box works.
    If the design is done right "no shading" you do not need it.....
    Might be a good fix for real world gridland problems in roof oriented systems!
    More stuff to sell also!
    It looks like your little piece of heaven is coming along! Good Luck!
    OK back to Defense!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Help me design the most efficient system

    Mike, I doubt he will be back, too many sceptics with knowlege here.

    however did you look at the movie? Up to the point where they start 'the pitch' It looks like a good primer on shade losses... comments?:confused:

    Eric
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: Help me design the most efficient system

    Looks like drive-by spam to me. I was wondering when the mods would send it to /dev/null.
  • BB.BB. Super Moderators, Administrators Posts: 32,642 admin
    Re: Help me design the most efficient system

    Generally, we try and let all sides get their information out.

    In this case, somebody asked about the vendor and they responded.

    You guys are doing a good job of asking the questions and the vendor has the choice of responding.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • SolarEdgeSolarEdge Registered Users Posts: 9
    Solar Edge [from: help me design the most efficient system]
    Nice marketing hype ... You can read our threads on the Enphase

    You can't change the way panels work ... temperature changes so does the vmp, same for shading.

    A Xantrex or SMA central inverter with a single string will outperform your system, perfect tracking ( exacty why is single panel tracking any different ? ), better efficiency, lower cost and decade of proven performance.

    With panels sizes today, you can do about 6kw in a single string. So for cost, performance, harvest and free monitoring, the Xantrex or SMA central inverters.
    mike90045 wrote: »
    Well, so how does your system work, with one panel in a string, shaded, and only producing 50W vs 200w like the others in the string?
    At the very least, the entire string would have to degrade by 150W.

    And "highly reliable" - is your module 20x more reliable than a central inverter ?
    (an average install being 20 or so panels). Got any data to convince
    a EE in the spacecraft industry? I know how MTBF stats are gamed.

    I appreciate the opportunity to answer some of the questions raised in this thread. I would be happy to further try to explain the architecture of our system.

    In a traditional PV system connected to a string inverter, the same current flows through all serially connected panels. In real-life conditions panels are not identical: mismatch caused by inherent nameplate tolerance, dust, mud, bird dropping, leaves, aging or shading means that some panels would require different current (different Impp) to produce their peak power. A standard inverter can only select one common current for all the string’s panels, so some potential power can be lost.

    In a SolarEdge system a PowerBox is connected to each panel and continuously tracks its specific MPP, independently of the other panels. In other words, each panel can get its own different optimal current, so power loss due to mismatch is eliminated.

    In traditional PV systems the string voltage would equal to the sum of all panel output voltages, which vary with string length, temperature and shading.
    In contrast, in a SolarEdge system the sting voltage remains fixed, at the optimal inversion voltage of the inverter, at all times, regardless of these factors.
    How? The PowerBox in itself is a DC-DC converter. On the panel side (PowerBox input) the PowerBox always maintains Impp/Vmpp specific to that panel (which does vary with irradiance and temperature). At the same time the PowerBox will output a different voltage, so that the sum of all PowerBox voltages always adds up to the fixed string voltage.
    For a more technical explanation of how this is done, take a look here: http://www.solaredge.com/files/pdfs/se%20-%20solaredge%20architecture%20overview.pdf

    With regards to the previous reliability question - SolarEdge provides a 20 year warranty for all PowerBoxes, including remuneration for PowerBox replacement and the labor involved. In addition, module-level monitoring allows accurate fault detection and faster resolution including automatically pinpointing the location of underperforming modules on a PV site map.

    Regards,
    Danya Golan, SolarEdge
  • russruss Solar Expert Posts: 593 ✭✭
    Re: Help me design the most efficient system

    Love the sales pitches - especially when it seems the salesman has recently moved up from garden equipment or ladies shoes department!

    İn building houses here İ run into the type all the time that are just selling something and have some small amount of misunderstood literature from some source.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,148 ✭✭✭✭✭
    Re: Help me design the most efficient system

    I would bet the "SOLAR EDGE" is made by National Semiconductor. It sounds exactly the same. The Sanyo bifacials are amazing and I do not doubt that with snow on the ground or a white color under the panels they would do exactly what Sanyo says. Those are the Sanyo's in my Avatar above.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help me design the most efficient system

    > A standard inverter can only select one common current for all the string’s panels, so some potential power can be lost.
    I always figured the panel with the lowest amps, set the max amps for the string, not the inverter. (standard old school MPPT)

    The brochure seems to imply that the Command and Control is via the web ? or is it the Inverter that controls the modules ?

    What is the loss in each DC-DC module ? For a 200W panel, I can't see it being any less that 10W converter loss (95% eff)

    What is the efficiency of the main Inverter?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    Re: Help me design the most efficient system

    PV panels have a relatively flat vmp point , note for the the sales guy, this means you can vary the voltage or current to get a similar maximum power point.

    When panels are matched to within the tolerance from the manufactures ( typically 5% and better with panels like Evergreen ) and are in a single string configuration your individual panels will all be at slightly different voltages yet the rated power will be at maximum, due to the flat IV curve. So a slightly "stronger panel can run at a reduced current and compensates by running a a slightly higher voltage

    Want to talk shading, single strings are BETTER than these distributed inverters as when in a string partial shading only takes out the shaded production. In a solar panel there are typically 3 or 4 strings of cells, protected with bypass diodes. When using a micro-inverter dedicated to a single panel, it can't run when ANY of the panel is shaded, you lose 100% of that panels generation where as in a string with the central inverter, the non-shaded cells with the shaded panel continue to produce power.

    So in simple terms on a per panel basis

    Micro inverter = ZERO output per panel when any part is shaded
    Central inverter = Only shaded cell/sting is lost, which means only 25-33% maybe lost on a panel.
  • a0128958a0128958 Solar Expert Posts: 316 ✭✭✭
    Re: Help me design the most efficient system
    SolarEdge wrote: »
    I appreciate the opportunity to answer some of the questions raised in this thread. I would be happy to further try to explain the architecture of our system....
    Danya Golan, SolarEdge

    Dear Mr. Golan, I have some questions, please:

    1. Does your product replace the connection box on the back of each panel, or, does is attach to the wires coming out from a panel's junction box?

    2. Does your product require use of a SolarEdge inverter, or, can any high quality appropriately-sized inverter be used?

    3. For the communication signals from each SolarEdge module, what kind of cable is required?

    4. Is your product field-installable, or, does it require panel manufacturer installation?

    5. What is the price for one SolarEdge module? in quantity?

    Thank you.

    Best regards,

    Bill
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Help me design the most efficient system

    sg,
    i think salespeople are so focused on the sale that they fail to realize who they could be putting that sales pitch to. he specified you to explain things to and he failed to read what it says below your username of solar guppy. you guys in general are handling it well in addressing sales pitches here and my advice is for solar edge to be a bit more careful as technically his pitch is violating the rules as nobody asked you to step in this time with the sales pitch, er info.:roll:
  • SolarEdgeSolarEdge Registered Users Posts: 9
    Re: Help me design the most efficient system

    Hi Mike,

    Answering your four questions:

    Without getting into how different inverters work, my point was that in standard systems the same current flows through all panels serially connected in a string. Panel’s IV curves have only one global maximum point, so every panel with a slight mismatch does not get its Impp and by definition loses some energy. In contrast, in a SolarEdge system each panel’s Impp is tracked independently by the PowerBox connected to it, so mismatched panels in a string will all operate in their different optimal currents to produce maximum power.

    MPPT per panel is done by each PowerBox independently and does not require command and control by the inverter. For the sake of performance-monitoring, each PowerBox measures panel data and transmits it over the PV power lines. The inverter has a built-in Power Line Communication receiver to collect data incoming from all modules. All data is then sent over the internet to enable web monitoring at module level.

    The PowerBox connected to each panel has DC-DC weighted efficiency of 97.7% (a PowerBox is NOT a micro-inverter). An inverter connected to one or multiple strings will then invert DC to AC at weighted efficiency of 97.2% (for our 3.3k, 4k, 5k, and 6k inverters).

    Danya, SolarEdge.
  • SolarEdgeSolarEdge Registered Users Posts: 9
    Re: Help me design the most efficient system

    1. Does your product replace the connection box on the back of each module, or, does is attach to the wires coming out from a module's junction box?Our PowerBoxes may either be embedded on the back of the module instead of the junction box (by module manufacturers), or attached as an add-on to the wires of the junction box (by PV installers.)

    2. Does your product require use of a SolarEdge inverter, or, can any high quality appropriately-sized inverter be used?SolarEdge inverter was designed for a PowerBox system: as such it has no MPPT function, works at a fixed string voltage, and includes a built-in power-line communication receiver for incoming module performance data. However, technically speaking, our PowerBoxes can work with some standard inverters as well.

    3. For the communication signals from each module, what kind of cable is required?
    Communication is carried out on the power lines, so no additional cables are required

    4. Is your product field-installable, or, does it require module manufacturer installation?
    The add-on PowerBox is field-installable, and the junction-box solution is embedded by module manufacturers and will be provided to installers pre-integrated.

    5. What is the price for one module? in quantity?Please send me an email for pricing.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Help me design the most efficient system

    I'm stupid. I admit that freely.

    I do not see how it is possible to take "X" Watts from a solar panel, run it through a device that will consume some of that energy to increase the output Voltage and come up with "1.25X" Watts.

    Can someone explain this?
  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    Re: Help me design the most efficient system

    Your losses for having essentially a mppt charge controller for each panel will exceed the improvements in the panel havest.

    This sound like the National Semi Magic Box ... which is they put a DC to DC converter at the end of a string to balance large multi sting installation with the big inverters. This product. looks the same but puts the DC to DC on each panel

    1)
    Your efficiency, just as a charge controller ( DC to DC switcher ) is not 97.7% at all power levels and at lower than the peak efficiency range will rob even more harvest from the panel.

    2) since you have a buck type switcher, when a partial panel is shaded, its below the output value so your converter puts out nothing.

    3) Vmp curves are very flat. While running in a string with a central inverter is a single current value thru all panels, this doesn't mean its the panel with the lowest vmp current is what the string is loaded too. From my work, its less than 1% hit when single strings with a string inverter find the maximum power for the string. You may have a panel or two that are running at lower currents, but they also run at higher voltages and hence the power loss from Pmax is negligible

    I honestly don't see a single condition that this will improve harvest, I welcome you to address the points above
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help me design the most efficient system
    I'm stupid. I admit that freely.

    I do not see how it is possible to take "X" Watts from a solar panel, run it through a device that will consume some of that energy to increase the output Voltage and come up with "1.25X" Watts.

    Can someone explain this?

    Do you want the salesman to explain it, or an Electrical Engineer ?
    As An EE, I can't.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help me design the most efficient system
    SolarEdge wrote: »
    MPPT per panel is done by each PowerBox independently and does not require command and control by the inverter. For the sake of performance-monitoring, each PowerBox measures panel data and transmits it over the PV power lines. The inverter has a built-in Power Line Communication receiver to collect data incoming from all modules. All data is then sent over the internet to enable web monitoring at module level.

    Ok, this one, I don't understand. In an earlier example
    On the panel side (PowerBox input) the PowerBox always maintains Impp/Vmpp specific to that panel (which does vary with irradiance and temperature). At the same time the PowerBox will output a different voltage, so that the sum of all PowerBox voltages always adds up to the fixed string voltage.
    How does each box in a string, know what the desired string voltage is, and adjust accordingly? The link to the PDF did not explain this bit of magic, other than I thought the special inverter talked back to the boxen and told them what to aim for.


    And the other thought, all the control and such, has there been any EMI susceptibility
    or emission testing? Do the parts and the whole pass FCC "B" emissions?

    What happens when your cell phone or wi-fi kicks in, and glitches the system.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • SolarEdgeSolarEdge Registered Users Posts: 9
    Re: Help me design the most efficient system
    Your losses for having essentially a mppt charge controller for each panel will exceed the improvements in the panel havest.

    This sound like the National Semi Magic Box ... which is they put a DC to DC converter at the end of a string to balance large multi sting installation with the big inverters. This product. looks the same but puts the DC to DC on each panel
    1) Your efficiency, just as a charge controller ( DC to DC switcher ) is not 97.7% at all power levels and at lower than the peak efficiency range will rob even more harvest from the panel.
    2) since you have a buck type switcher, when a partial panel is shaded, its below the output value so your converter puts out nothing.
    3) Vmp curves are very flat. While running in a string with a central inverter is a single current value thru all panels, this doesn't mean its the panel with the lowest vmp current is what the string is loaded too. From my work, its less than 1% hit when single strings with a string inverter find the maximum power for the string. You may have a panel or two that are running at lower currents, but they also run at higher voltages and hence the power loss from Pmax is negligible
    I honestly don't see a single condition that this will improve harvest, I welcome you to address the points above

    Solar Guppy:

    1) 97.7% is the weighted efficiency, not the peak efficiency.
    2) The PowerBox supports buck, boost, and buck-boost modes. It’s compatible with wide panel voltage range: 5v-60v for c-Si, or 10v-95v for TF. Therefore the PowerBox harvests power well from partially shaded panels, even when one or more bypass diodes kicks in.
    3) I agree with you that the degree of power loss varies with the degree of mismatch, and will be lower in sites with a single string per inverter. Nevertheless, our partners have measured added energy in SolarEdge side-by-side installations, which originated from various conditions, including centralized inverter slower tracking of fast moving clouds, uneven panel soiling, growing mismatch as panels age, locking on wrong peaks in multi-string sites, and under voltage on hot days. 3rd party analysis under various test conditions, including single string, was performed by PHOTON labs and reported last September in Germany.

    mike90045 wrote: »
    Ok, this one, I don't understand. In an earlier example
    How does each box in a string, know what the desired string voltage is, and adjust accordingly? The link to the PDF did not explain this bit of magic, other than I thought the special inverter talked back to the boxen and told them what to aim for.

    And the other thought, all the control and such, has there been any EMI susceptibility
    or emission testing? Do the parts and the whole pass FCC "B" emissions?

    What happens when your cell phone or wi-fi kicks in, and glitches the system.

    Mike:
    You can find an explanation of the fixed string voltage concept of operation on pages 6 and 7 of that PDF.

    Power-line communication is used for sending panel performance measurements for sake of high resolution monitoring and maintenance. Therefore EMI does not risk power production. In any case, the system passed FCC class B certification.
    I'm stupid. I admit that freely.
    I do not see how it is possible to take "X" Watts from a solar panel, run it through a device that will consume some of that energy to increase the output Voltage and come up with "1.25X" Watts. Can someone explain this?

    Cariboocoot:
    The catch is that you're not comparing the same "X Watts" anymore...
    Let's take an easy example to simplify the argument. Consider a standard inverter connected to two strings with some partial shading in one string. As explained by BB and Solar Guppy in other threads, you're may lose power from non-shaded panels, because of the unequal VMP between strings and possibly also locking of the inverter on a local maximum of the resulting complex "merged" I/V curve. Adding PowerBoxes to these panels will eliminate power loss from non-shaded panels, and prevent locking on local maximum, because MPPT will be performed individually per panel. So, in total, you get a greater "X Watt" to start with, at the expense of a negligible DC-DC conversion consumption.

    -

    By the way, although this thread dissects primarily energy output, I think there's more to system "efficiency" alone - in some cases a given roof space can be better utilized thanks to connecting to the same inverter strings with unmatched length, orientations, and panels models; and by creating longer strings (8-25 panels) which maintain their fixed string voltage without risk of over voltage. Module-level monitoring means that faults can be detected at higher resolution. Last, automatic shutdown of each panel DC voltage ensures safer installation, maintenance, and firefighting.
  • heynow999heynow999 Solar Expert Posts: 80 ✭✭✭✭
    Re: Help me design the most efficient system

    ummm, pretty cool tracker, eh?
  • carotenecarotene Registered Users Posts: 8
    Re: Help me design the most efficient system
    SolarEdge wrote: »

    The PowerBox connected to each panel has DC-DC weighted efficiency of 97.7% (a PowerBox is NOT a micro-inverter). An inverter connected to one or multiple strings will then invert DC to AC at weighted efficiency of 97.2% (for our 3.3k, 4k, 5k, and 6k inverters).

    Danya, SolarEdge.

    So if my math is correct, the overall weighted conversion eff is 94.96% from panel to grid AC?

    solaredge has an interesting approach - very creative. It's really going to boil down to cost. I've read some of their case studies on savings in wiring. The examples, of course, lean in their favor in terms of layout challenges.

    Most business/commercial installations probably won't use them. Why? Flat roof, no obstructions, no shading. Why use 10,20, or more dc-dc converters (and increase the system's electronic component count substantially) when just 1 converter in a centralized inverter will do just fine?

    I understand that sometimes shading is unavoidable and many new homes have multi-pitch and fancy hipped roofs, but good site planning can usually avoid shading during the charging hours that count. Many centralized inverters are now featuring multi-string input. If they can at least track string by string, that will solve 90% of the problems out there IMO.

    It's interesting times with this product, enphase, and the rest. We seem to be grappling with what resolution of tracking is necessary. If costs of PV continue to decline, cost pressures will continue to shift towards the conversion electronics. It will be tough for solaredge, enphase, and others to compete with central inverters on cost.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,987 ✭✭✭
    Re: Help me design the most efficient system
    carotene wrote: »
    It's interesting times with this product, enphase, and the rest. We seem to be grappling with what resolution of tracking is necessary. If costs of PV continue to decline, cost pressures will continue to shift towards the conversion electronics. It will be tough for solaredge, enphase, and others to compete with central inverters on cost.

    Very true ... Solar PV panels looks to be 2 bucks for UL Si soon ... to have a distributed inverter typology would likely be dollar a watt ( figure 200 bucks for one of those panel converters minimum ) and you asking for a 50% cost increase to use this or the enphase.

    Looks to me like some big company's getting into the Gridtie market and instead of improving the central inverter are going after red-herring solutions. I'm not saying it won't sell, but for a properly designed GT system, it adds a significant cost on a per watt basis.

    Cost WILL be paramount, and if PV continue to decline in price everything else will be sticking out big time for similar cost improvements. Using 30 of something instead of one ( inverters, converters whatever ) can't be a winning solution in a declining price market
  • BB.BB. Super Moderators, Administrators Posts: 32,642 admin
    Re: Solar Edge [from: help me design the most efficient system]

    Have moved to own thread. Original thread is here:

    Help me design the most efficient system

    -Bill "Moderator" B.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Edge [from: help me design the most efficient system]

    I'm glad Bill split this out; an interesting discussion that was getting far, far away from the OP.

    So if I understand this right, the basis is that an inverter has an optimum input Voltage and the idea is to keep the array Voltage at this point so that DC to AC conversion remains at 97% efficiency (roughly)? This would be as opposed to allowing the Voltage and thus the conversion efficiency to drop. In that case, the benefit would be dependent on a gain differential of Optimum Voltage @ Less Current converting to AC @ 97% vs. Non Optimum Voltage @ Greater Current (equivalent Watts) converting to AC @ <97% and taking into account the power consumption of the DC-DC converters.

    I could have that totally wrong; so far no one has explained how this works in real world terms.

    But if that is the case I have to wonder about its viability. Normally grid-tie inverters are designed to run on a fairly wide range of Voltage, with a minimum threshold and a maximum limit. Within that range they average better than 90% efficiency across varying conditions. It sounds like this product would be squeezing out one or two percent efficiency under a fairly narrow set of circumstances compared to a well-designed array. And at what expense? Chances are the cost of the units (one per panel?) collectively would exceed the cost of additional PV's which would more than make up the difference and probably prove more reliable in the long term.

    Again, maybe I'm completely wrong in my analysis. And if I don't understand it, does anyone?
  • BB.BB. Super Moderators, Administrators Posts: 32,642 admin
    Re: Solar Edge [from: help me design the most efficient system]

    Thank Solar Guppy and Niel for getting on my case to split the thread. :D

    I was getting a bit lazy there. :blush:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • a0128958a0128958 Solar Expert Posts: 316 ✭✭✭
    Re: Solar Edge [from: help me design the most efficient system]

    I think I understand what the SolarEdge product is supposed to do - here's an example (without comment on its cost effectiveness, or its features not related to power generation (i.e., 'switch' to turn off each panel for maintenance, individual panel performance monitor, etc.)).

    The example is 2 strings in parallel with shading on 1 panel in just 1 of the 2 strings. Each string is 13 panels. Each panel is 225 W (Pm): 28.66 Vmp and 7.68 Imp

    Assume first all 26 panels are in full sun:

    Each string's Pm = 2928 W = 7.86 A * 28.66 V * 13 panels. Total array power is 2928 W * 2 strings = 5856 W. Imp = 7.86 A * 2 = 15.7 A and Vmp = 28.66 V * 13 panels = 373 V.

    Now assume one panel in String 2 goes fully unshaded, making the string in essence a 12, not 13 panel string (assume panels have diodes).

    String 1 is still operating at Pm=2928 W (7.86 A and 373 V)

    Each panel in String 2 is forced to operate at a higher voltage now such that the aggregate is still 373 V to match String 1; i.e., 373 V / 12 = 31.1 V.

    From the panel's I-V curve, at 1.0 Sun, the remaining 12 panels' current is reduced to 7.5 A.

    String 2 now operates at P = 373 V * 7.5 A = 2798 W.

    Array power is reduced from 5856 W to 2928 + 2798 = 5726 W, a 2% reduction.

    Now assume the SolarEdge product is installed, where the MPPT function is moved from the inverter to being distributed to each panel's SolarEdge product's intelligence.

    My guess is the product will find a different different array I-V operating point, such that there's, say, a 1% loss instead of the 2% loss without the SolarEdge product.

    This example obviously doesn't illustrate cost effectiveness. But, my guess is the worse the shading problem is the better the SolarEdge product can find find a higher power I-V point, at least according to the marketing pitch.

    Best regards,

    Bill
  • BB.BB. Super Moderators, Administrators Posts: 32,642 admin
    Re: Help me design the most efficient system
    SolarEdge wrote: »
    2) The PowerBox supports buck, boost, and buck-boost modes. It’s compatible with wide panel voltage range: 5v-60v for c-Si, or 10v-95v for TF. Therefore the PowerBox harvests power well from partially shaded panels, even when one or more bypass diodes kicks in.

    For anyone interested in types of switching digital power supplies, here are a few links:

    Switch Mode Power Supply

    Major types of Non-Isolated switch mode power supplies (from above link):

    boost converters
    buck converters
    buck-boost converters

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Solar Edge [from: help me design the most efficient system]

    some of you may be wondering where i fit into this and if i'm doing my duty as i could've split the thread too. for the record i was opposed to the utterings of solaredge from the beginning as my take on this was it was spammish. if it were my decision it wouldn't have gone this far that bb would've needed to rescue the thread for the op. it was invited though and i left the responsibility of the thread up to bill in advance if any deemed it flaky or if it got further out of bounds. when sg complained that it took away the thread from the op i rightly complained to bb on it.:-)

    edit to add:
    i would not have mentioned this if i was not mentioned as complaining to bill on this.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar Edge [from: help me design the most efficient system]

    Every now and then it's probably a good idea to go this route; take the claims of a manufacturer/salesman and openly discuss them to see how well they stand up to scrutiny. Remember that the average consumer can't do this sort of analysis on his/her own.

    Despite being foggy this week, I think I've come to the conclusion that this product tries to get a partially shaded panel to behave like a lower Wattage panel but at the same Vmp as the rest of the string by boosting the output Voltage from the 'shaded Vmp' point to match that of 'unshaded Vmp'. I'm not convinced it would work, much less that it would be practical. And I don't think SolarEdge did a very good job of explaining how his product supposedly functions.

    Enough criticism!

    Wishing everyone Merry Christmas, Happy Chanukkah, Joyous Whatever-Holiday-You-Like-To-Celebrate!
    And thank heavens the Solstice is past and all our panels will be gaining output (except down under, of course).:D
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