Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide

Which panel would you prefer?

I finally found a local source for these panels, but I can't decide on which one to get. I only need 1 panel to work with my SunSaver MPPT controller in a simple off-grid setup.

My thoughts on each:

Sharp 170:
$4.20/watt - cheapest of 3 choices
34.8 Vmp - minimizes voltage drop (I have a 85 ft run between panel and controller with 8 AWG)
Maybe made in USA? They have a solar plant in Memphis, TN but I'm not sure that is where these are made.
worst power guarantee -5%/+10%

SolarWorld 175:
$4.66/watt
made in USA
35.8 Vmp
Monocrystalline - is that really an advantage over poly?

Evergreen 190:
$4.73/watt
made in USA
higher wattage - more closely matches my controller maximum
smallest carbon footprint (string ribbon)
best power guarantee -2%/+2.5%
lower Vmp than other 2 choices & 26.7v (more voltage drop)


I'd really like to support US solar manufacturing in this weak economy. I couldn't compare temperature coefficients since I couldn't find any specs for the Sharp panel.. so not sure which panels have the most drop per degree.

For low Irradiance, it looks like Evergreen wins.. from the specs it looks like it looses 0% efficiency for 200w/sq.meter.. The SolarWorld looks like it looses 5%. I can't find anything on the Sharp specs for low irradiance.. so who knows..

Am I over analyzing? Am I missing anything?

Thanks!
James

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,634 admin
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide

    Solar Guppy or one of the other designers here can probably give you more accurate information--but the basics:

    If you are looking at voltage drop as the temperature increases--make sure you divide the drop by the panel voltage--so that all drops are "normallized". The voltage drop is bascially on a per silicon wafer basis. So a 26 volt panel will have more drop per degree C vs a 12 volt panel--when the specifications per cell are actually the same. (the % voltage drop per C is the same).

    Looking at panel Vmp voltage is OK--but also look at string voltage. You may put 4 lower voltage panels or 5 higher voltage panels in series and have the same string voltage and current.

    Mono vs Poly-silicon--pretty much shop on price ($/watt) and surface area... You will get a tiny bit more power from Mono crystalline silicon per square foot vs Poly. But if you have the room to mount--it may not be worth the price difference (be sure to include the costs of the wiring and frame work too). If you have astetic issues--the Mono Crystalline panels don't have that "fractured purpley glass" look--if that is important to you (or your wife).

    For me, a good place for a quick lookup of any solar panel specs. is the Xantrex GT design web site... They have hundreds of solar panels and list the basic specifications when you choose one to model.

    Sharp NE-170U1
    Max Power Voltage - Vmp 34.8 Vdc
    Open Circuit Voltage - Voc 43.2 Vdc
    Voltage Temp Coeff - Vtoc -0.144 V/°C
    STC Rating - Pmp 170 Wstcdc
    Max Power Current - Imp 4.9 Adc
    PTC Rating 149.9 Wptc

    Solar World SW175
    Max Power Voltage - Vmp 35.4 Vdc
    Open Circuit Voltage - Voc 44.6 Vdc
    Voltage Temp Coeff - Vtoc -0.145 V/°C
    STC Rating - Pmp 175 Wstcdc
    Max Power Current - Imp 4.95 Adc
    PTC Rating 162.7 Wptc

    Evergreen ES-190-RL
    Max Power Voltage - Vmp 26.7 Vdc
    Open Circuit Voltage - Voc 32.8 Vdc
    Voltage Temp Coeff - Vtoc -0.1148 V/°C
    STC Rating - Pmp 190 Wstcdc
    Max Power Current - Imp 7.12 Adc
    PTC Rating 167.2 Wptc

    Hmmm... I wonder if there is an error in the Xantrex Data base or not... Look at the PTC rating for all of the panels (probably what you should be basing your $$/Watt calculations on--PTC is the rating from the California Energy Commission and should be the most accurate when comparing across brands/models). The Wptc are not tracking the Manufacturer's STC ratings that closely...

    Evergreen "190" which is supposed to have the tightest power spec. ratings is hardly 6.5 watts more power than the Solarworld "175" should be closer to a 15 watt delta. And the the Sharp "170" is almost 13 watts less than the Solarworld "175" -- which should have only been a 5 watt difference.

    Note that the V/°C for the Evergreen is less than the other two panels--but that is because it is also a lower voltage panel:

    Evergreen:
    -0.1148 V/°C / 26.7v = -0.43%/°C

    Solar World:
    -0.145 V/°C / 35.4v = -0.41 %/°C

    Evergreen's V/°C drop is slightly more than the Solar World when normalized. (5% difference between brands is probably not a significant difference in voltage drop for most installations).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 8,420 ✭✭✭✭✭
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide
    JDR*energy wrote: »

    For low Irradiance, it looks like Evergreen wins.. from the specs it looks like it looses 0% efficiency for 200w/sq.meter.. The SolarWorld looks like it looses 5%. I can't find anything on the Sharp specs for low irradiance.. so who knows..

    Am I over analyzing? Am I missing anything?

    Thanks!
    James

    In your installation, will you be at a "good" sun angle, or just "wherever it lays down" ?

    Don't just lay it on the roof, heat trapped under it (that blue/black color really gets hot!) will lower your voltage output.
    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: 1,962 ✭✭✭
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide

    I'd go with the Evergreen, I can't find any data on the Solar World PTC or Sharp PTC numbers on there data sheet

    Solar World:
    http://lib.store.yahoo.net/lib/wind-sun/SW-175-Mono.pdf more recent version

    Sharp:
    http://www.sharpusa.com/files/SESG-170U1.pdf

    Evergreen: Which has some form of PTC on the data sheet
    http://www.evergreensolar.com/upload/195W_Product_Datasheets/S195_US_010408.pdf


    Since the ONLY certified value is STC, use that value for comparision, PTC not spec'ed from the manufacture is worthless and as BB's post showes that
  • JDR*energyJDR*energy Solar Expert Posts: 30
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide

    thanks BB for the "normalized" info on the voltage drop. I didn't realize that before. Also.. thanks for the Xantrex link. That is a nice quick way to compare modules!

    For the PTC issue... that is the correct value for the Evergreen. I just realized it was in their spec sheet (Pptc=168.8 ) http://www.evergreensolar.com/upload/195W_Product_Datasheets/S195_US_010408.pdf

    I think the Xantrex data is the older data. This site below shows that the Evergreen data has been updated in 2/2007. And the new info matches the evergreen specs.
    http://www.gosolarcalifornia.ca.gov/equipment/pvmodule.php

    Here is an interesting PDF on Evergreen. It compares the PTC coefficient vs. some other panels... it seems pretty good (168.8/190 = .888 ) but when you compare it to the SolarWorld it doesn't come close (162.7/175 = .929):
    http://www.planitsolar.com/pdf/evergreen.pdf

    And reading this blurb from www.beyondoilsolar.com, it makes me believe the SolarWorld is slightly more efficient at extracting extra power in non-ideal situations.. which also corresponds to the differences between mono and poly silicon:

    "Rating the output of Photovoltaic Panels using STC and PTC.
    The PTC also accounts for the fact that the sun is only close to perpendicular to the panels for brief period of time at high noon.. At other times the sun hits the panels at various angles. The PTC averages the yearly output while taking this into consideration"

    It seems like if I had a sun tracker, the PTC value would be worthless.. But otherwise it seems fairly useful.

    mike90045,
    if I can find the right mounting rack/rails I am going to attempt a "good" angle. That should help with output as well as temperature. Since this is a 1 panel system, I'm trying to maximize efficiency.

    Solar Guppy,
    That is one complaint I have with SolarWorld and Sharp.. their spec sheets are pretty light. Evergreen seems to be much more thorough with their details.
  • BB.BB. Super Moderators, Administrators Posts: 29,634 admin
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide

    Here is a nice link that shows how to compare solar panels against each other (do a little spec. hunting and spreadsheet analysis)... This site is biased towards the Sanyo HIT hybrid panels--which I would suggest careful scrutiny about before buying...

    I am not sure I would toss the PTC spec. away as being completely useless... It is based on several actual panel parameters--and can be "adjusted" by the manufacturer if they believe the numbers are in their favor:
    So the industry came up with a better testing protocol -- called "Photovoltaics for Utility Scale Applications" (PV-USA) or PVUSA Test Conditions (PTC). PTC were developed at the PV USA test site in Davis, California and represent a more real life condition of 20 degrees C. ambient temperature (68 F.), 10 meters above ground level, and wind speed of 1 meter per second. As PV cells average about 20 degrees C. above ambient temperature in the real world (104 F.) and cell voltage drops as temperature increases, a PV module's power output in real life conditions will always be lower than the power measured at the factory where cell temperature is maintained at a controlled 77 degrees F. (25 C). But since there are differences in technology and manufacturing processes, the ratio of PTC to STC can vary dramatically. So the first lesson in evaluating PV modules is to ignore the nameplate rating and go right for the PTC ratings. But some manufacturers don't publish these data on their spec sheet. (!) Don't worry, you can look up any module sold in California here (The CA Energy Commission's web site), and here are some of the best selling ones.

    Given that, at least in California, PTC=$$$ (cash rebates), manufacturers of current products have every reason to "tweak" their specs. to the California Solar Program's rebate program's requirements.

    As I understand Solar Guppy, and looking at a few sites yesterday and today--for example Xantrex uses a different Vmppt range when listing the CEC ratings vs the their "real ratings" to get a 1% better number. Another Mfg. was pointed out yesterday (SMA?) appeared to be doing the same thing too.
    GT4.0N:
    MPPT voltage range (CEC & CSA): 240 - 480 Vdc
    MPPT operating range: 235 Vdc - 550 Vdc

    Not that this is really wrong (and who is going to really be able to accurately measure 0.5-1.0% differences with a home installed inverter).

    Perhaps, as SG says, PTC numbers are not worth using when comparing panels--but the generically available PTC numbers are usually much closer to predicting actual array output vs the STC numbers in my sample size of 1.

    :confused:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • newenergynewenergy Solar Expert Posts: 291 ✭✭✭✭✭✭
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide

    They all make modules in the US as well as outside.

    Sharp has manufacturing somewhere in southern California.

    Evergreen's SL and VL modules are made in the US and the RL and TLs are made in Germany.

    Solarworld has manufacturing in Camarillo and is just opening a huge plant in Oregon. I've met with some people who work there in Camarillo and they say they make more modules in the US than anyone else.

    The CEC-PTC ratings are:

    ES190 = 168.8W
    Sharp170 = 149.9W
    SolarWorld 175 = 156.6W

    I get the ES195s for the same price I can get SW175s. Maybe you should shop a little more. You might look at sunelec.com for really cheap prices on Evergreens. I've never bought from them, but others around here have.

    From an environmental point of view I think the Evergreens are the winner. At least they should beat the SolarWorlds because I think in general monocrystaline modules have considerably longer energy payback.
  • JDR*energyJDR*energy Solar Expert Posts: 30
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide
    newenergy wrote: »
    I get the ES195s for the same price I can get SW175s. Maybe you should shop a little more. You might look at sunelec.com for really cheap prices on Evergreens. I've never bought from them, but others around here have.

    From an environmental point of view I think the Evergreens are the winner. At least they should beat the SolarWorlds because I think in general monocrystaline modules have considerably longer energy payback.

    Where do you get your ES195s from?

    I live near the NJ-PA border, and I have searched everywhere and called/contacted upwards of 20 installers in the area. I can't find anything cheaper.

    I have called sunelec.com (and many other online stores), and unfortunately the price to ship 1 panel adds on average $175 to the cost. Since I only need 1 panel (maybe 2 if I can find a good price), anything that involves shipping doesn't seem to be a valid option for me.

    The price for the SW175 in my first post was from mrsolar.com, and that was me driving to Baltimore, MD to pick it up from their warehouse.

    Yes the Evergreens are the best in environmental terms.. they use less chemicals, less silicon, and less energy to make each panel. Energy payback is like 15 months according to http://www.evergreensolar.com/
  • stimpy17stimpy17 Registered Users Posts: 8
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide
    JDR*energy wrote: »
    Where do you get your ES195s from?

    I live near the NJ-PA border, and I have searched everywhere and called/contacted upwards of 20 installers in the area. I can't find anything cheaper.

    I have called sunelec.com (and many other online stores), and unfortunately the price to ship 1 panel adds on average $175 to the cost. Since I only need 1 panel (maybe 2 if I can find a good price), anything that involves shipping doesn't seem to be a valid option for me.

    The price for the SW175 in my first post was from mrsolar.com, and that was me driving to Baltimore, MD to pick it up from their warehouse.

    Yes the Evergreens are the best in environmental terms.. they use less chemicals, less silicon, and less energy to make each panel. Energy payback is like 15 months according to http://www.planitsolar.com/pdf/evergreen.pdf

    Hello,
    Although I have NO practical experience (as in bolt to my roof and reap the rewards) with the Evergreen panels(why you might ask? Because in the act of doing research and collecting panels they dis-continued my 115-GL's. I just needed 1 more!!!!) Now I'm not a solar MR. Wizard but IMHO don't wait to round-out your system. Bad things happen.
  • JDR*energyJDR*energy Solar Expert Posts: 30
    Re: Sharp 170, SolarWorld 175 or Evergreen 190 -can't decide
    stimpy17 wrote: »
    Now I'm not a solar MR. Wizard but IMHO don't wait to round-out your system. Bad things happen.


    that is probably good advice since technology changes so fast, who knows what products will still be available when you need them in the future.

    Lucky for me I'm just starting my system, and another plus is mine won't be grid tied. So I have a lot of flexibility. I'm just looking for a good (large) panel at a great price.
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