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bewildered by panel choices for DIY system

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  • nwdiver
    replied
    Originally posted by RShackleford View Post
    Despite the impressive price for the density of the REC panel, I'm not sure it's worth it for me over something like the Talesun 270 watt panel at $0.36/watt. Also wondering if its low price is a reflection of quality, or simply typical for such a low power density.

    Agreed; If you're not space constrained and want the most cost-effective system I certainly would not pay >$0.40/w for panels.

    ~All panels and cells are manufactured to roughly the same standard. I've never seen a significant difference in quality. I would never hesitate to buy panels from a company with a large scale manufacturing plant.

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  • RShackleford
    replied
    Originally posted by J.P.M. View Post

    If their spec sheet claims hold up, they might be a reasonable and less expensive (and available for DIY) alternative to Sunpower with respect to an identified need for a high power density for an application.
    Despite the impressive price for the density of the REC panel, I'm not sure it's worth it for me over something like the Talesun 270 watt panel at $0.36/watt. Also wondering if its low price is a reflection of quality, or simply typical for such a low power density.


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  • scrambler
    replied
    Originally posted by RShackleford View Post
    Places that make me "call for a quote" make me nervous though. Especially when it says stuff about wholesale rates for installers etc. Wonder if I can really see that $266 price on a paltry 15-16 panels to a DIY'er.
    I do not know if they sell to DIYer, they may only sell to installers and quote based on quantity, but it does not hurt to ask

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  • J.P.M.
    replied
    Originally posted by Mike90250 View Post

    If the half cells are twice as efficient, that might be true, but I know of no breakthrough allowing 355w panels to be smaller than 250W panels.

    355w is still going to take up some real-estate, be heavy and act like a sail.


    43 lbs, 68" x 40" , 20.3% eff
    If their spec sheet claims hold up, they might be a reasonable and less expensive (and available for DIY) alternative to Sunpower with respect to an identified need for a high power density for an application.

    S.P. still can have a higher power density at their top end panel (221 W/m^2), but for the same STC array size, the older, still avail. and still viable workhorse S.P. 327's at 200.1/m^2 will require more roof real estate than the REC 355's at 204 W/m^2 by just a bit. And they are not avail. for DIY.

    The REC is a bit bigger, 1.74 m^2 vs. 1.63 m^2 for the S.P., but a bit lighter, at 19.5 kg, vs, 20.6 kg. for the S.P.

    Still, the ~ 7% greater surface area for the REC panel is indeed an assembly consideration, especially on a windy day.

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  • RShackleford
    replied
    Originally posted by Mike90250 View Post
    355w is still going to take up some real-estate, be heavy and act like a sail.

    43 lbs, 68" x 40" , 20.3% eff
    Looks pretty comparable to the other panels I'm considering. Look at the snapshot of my spreadsheet I posted above.

    Places that make me "call for a quote" make me nervous though. Especially when it says stuff about wholesale rates for installers etc. Wonder if I can really see that $266 price on a paltry 15-16 panels to a DIY'er.


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  • Mike90250
    replied
    Originally posted by nwdiver View Post
    ....................... And those are half-cells so it's not much bigger than a standard 60 cell and much smaller than a 72 cell.
    If the half cells are twice as efficient, that might be true, but I know of no breakthrough allowing 355w panels to be smaller than 250W panels.

    355w is still going to take up some real-estate, be heavy and act like a sail.


    43 lbs, 68" x 40" , 20.3% eff

    Leave a comment:


  • scrambler
    replied
    Originally posted by Mike90250 View Post

    That's gonna be an armload up on a roof !
    They are almost the same size as LG 325 or Qcell 325 (67.75 x 40)

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  • scrambler
    replied
    Originally posted by RShackleford View Post
    Wow. What vendor ?
    Solar Electric Supply
    https://www.solarelectricsupply.com/...ce-solar-panel

    Leave a comment:


  • nwdiver
    replied
    Originally posted by Mike90250 View Post

    That's gonna be an armload up on a roof !

    I think the OP is doing a ground mount. And those are half-cells so it's not much bigger than a standard 60 cell and much smaller than a 72 cell.

    Leave a comment:


  • Mike90250
    replied
    Originally posted by scrambler View Post
    I just found out that the new REC alpha will be available in 355W panels in a couple of weeks........
    That's gonna be an armload up on a roof !

    Leave a comment:


  • RShackleford
    replied
    Originally posted by scrambler View Post

    I just found out that the new REC alpha will be available in 355W panels in a couple of weeks for $0.75/W ($266 for 355 watts) which is quite nice for a panel of that quality
    -0.26 temp coef
    Cut Cell panel (6 strings of 20 cells)
    92% production warranty at 25 years
    20 years product warranty
    https://www.recgroup.com/sites/defau...v_b_en_web.pdf
    Wow. What vendor ?

    Leave a comment:


  • scrambler
    replied
    Originally posted by RShackleford View Post
    I've made a spreadsheet to compare a variety of specific panels, configuration (number of panels and landscape/portrait), etc.
    I just found out that the new REC alpha will be available in 355W panels in a couple of weeks for $0.75/W ($266 for 355 watts) which is quite nice for a panel of that quality
    -0.26 temp coef
    Cut Cell panel (6 strings of 20 cells)
    92% production warranty at 25 years
    20 years product warranty
    https://www.recgroup.com/sites/defau...v_b_en_web.pdf

    No dates and price yet on the 380Watt version

    Leave a comment:


  • nwdiver
    replied
    Originally posted by RShackleford View Post
    What can be got wrong there ? Are you talking about azimuth & elevation, or more subtle issues ?

    Well.... your panels can blow away; We used new racking from unirac that had poor lateral support for the end panels and one of the panels broke loss in a storm. We're lucky the entire top row didn't 'unzipper'.

    Originally posted by RShackleford View Post

    Yeah, I saw those. Doing ground-mount, I'm not so space-constrained. Nor do I have a rigid idea of how many watts I need.

    I've made a spreadsheet to compare a variety of specific panels, configuration (number of panels and landscape/portrait), etc. I assume a $50 optimizer on every panel (Tigo TS4-R-O)
    If you're doing a ground mount and you're trying to keep your costs low I wouldn't use optimizers. Rapid Shutdown is only required for roof mount. There's no ROI especially if you can buy panels for $0.36/w and you're not space constrained. I guarantee that every $1 spent on optimizers will be >5x more productive if you just buy more panels.
    Last edited by nwdiver; 11-07-2019, 05:44 PM.

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  • RShackleford
    replied
    Originally posted by Paul Land View Post

    1/2 (50%) of the day is Night and it's dark
    Don't think a chainsaw will help too much with that. And really, the vast majority of your production comes from about a 6hr period centered around local noon.

    Leave a comment:


  • Paul Land
    replied
    Originally posted by RShackleford View Post
    Not sure where "half the day/night" comes from, but yeah, only 70% if I believe the 30% shading.

    I have a good chainsaw. But I have a LOT of trees.

    1/2 (50%) of the day is Night and it's dark

    Leave a comment:

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