bewildered by panel choices for DIY system

[nwdiver]

Worth the extra cost and imperfect appearance ?

So what do folks think of these brands, and are there others that might be more attractive to me ?

IMO panel choice is the least important consideration; Even racking is more important. If you want black panels for aesthetics get black panels. If you're space constrained get higher wattage panels; If you're on a budget get the cheapest ones (So long as they're UL) even 'B' grade is fine IMO. I've bought B grade.... it's usually just a cell misalignment that doesn't effect performance and can only be see if you're on the roof inches away from the panel.

If cost is a concern Renvu is selling Talesun panels for $0.36/w.

[RShackleford]

Even racking is more important.

What can be got wrong there ? Are you talking about azimuth & elevation, or more subtle issues ?

[Paul Land]

That's a very good question, to which I don't know the answer. All I know is that it's an input to PVWatts, and it's the number an installer used in PVWatts to estimate the number of kwh I should generate per year (a number which they are guaranteeing). The installer came up with the number by getting up on my roof with some sort of electronic device.


I am planning ground-mount. One reason being that the location would be a bit sunnier, though not dramatically so, than the roof.

Soooooooooo! You have 5 acres and it only gets a total of 70% Sun half the day/night that's an 80% loss? Invest in a really good chain-saw. Problem solved.

[RShackleford]

If cost is a concern Renvu is selling Talesun panels for $0.36/w.

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) and $3500 in add'l costs that are fixed regardless of these other choices (inverter, racking, structure, basically from the OP of this thread). Doing that, a 15 panel system with the Canadian 320watt panels is not much more per watt ($1.54) than the Talesun would be ($1.46), and gives me a good bit more wattage (4800 versus 4050). IOW, those bargain panels don't help me that much because of all the other costs.
Screen Shot 2019-11-07 at 4.04.22 PM.png
The "panels $" column is a little hinky, because the various panels come from different vendors, all of whom compute shipping separately (flat fee, or some value the shopping cart just computes based on weight or something).

[RShackleford]

Soooooooooo! You have 5 acres and it only gets a total of 70% Sun half the day/night that's an 80% loss? Invest in a really good chain-saw. Problem solved.

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.

[Paul Land]

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

[RShackleford]

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.

[nwdiver]

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'.

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.

[scrambler]

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/default/files/documents/ds_rec_alpha_series_ul_rev_b_en_web.pdf

No dates and price yet on the 380Watt version

[RShackleford]

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/default/files/documents/ds_rec_alpha_series_ul_rev_b_en_web.pdf

Wow. What vendor ?

[Mike90250]

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 !

[nwdiver]

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.

[scrambler]

Wow. What vendor ?

Solar Electric Supply

https://www.solarelectricsupply.com/rec355aa-355w-rec-alpha-low-price-solar-panel

[scrambler]

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)

[Mike90250]

....................... 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