Help, which panel to use?
skgolfer Registered Users Posts: 7 ✭
Hi, I am working with two vendors in the NJ area. One is trying to convince me to use Evergreen the other Sunpower. The Evergreens I know are a little larger and I will not be able to put quite as many on my roof but will still be able to install an adequate system 8.1kw system. The Evergreen's installed are coming in at $6/kw and the Sunpower at $6.5/kw. Same warranties. Is one panel better than the other. Will be using the 210s. Thanks.
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My 2 cents USD...
They are probably both good panels (for sure, the Evergreens are).
The one major issue that I am aware of is Sunpower requires Positive Grounding of their solar panels to keep their power output high (at spec.)... If you negative ground the panels, their output falls by some xx% (significant amounts). It is temporary, and connecting as positive ground brings them right back to spec.
For the end user, with proper equipment (inverter configured for positive grounding) -- everything is just fine.
The issue is that Positive Grounded Inverters are special order (if offered) and you may end up with a delay waiting for them to repair yours (instead of sending a refurb'ed unit from stock).
For off-grid systems... Positive Ground Charge Controllers are not common (if any are available)... So, if you run a positive solar panel, then you need to run your battery bank as a positive ground (done normally for telephone systems). A bit of pain to do the install.
In the end, with good quality vendors, purchase on $$$/watt installed.
I'm not sure if any or all of the Sun positive grounding issues have been resolved. That may not be the issue it once was. There have been several white papers on the subject, and I have never seen a definitive answer from Sun.
A bigger issue is that while Sun panels are indeed well built, quality panels, I don't think they carry a UL listing, even though they are made to those specs. Solar Guppy is the resident expert on Sun panel. I suggest you pose the question to him on his site if need be. http://www.solar-guppy.com/forum/index.php
the sunpower panels do have a high efficiency and still do require positive grounding. the positive grounding may or may not pose a problem for you, but most solar accessories do accommodate both grounds now i believe. the higher efficiency does command a higher price too as you noticed. if getting every bit of power per space isn't important i would personally go the cheaper route and not have to worry about using a more commonly used negative ground.
i know you are looking for something to make up your mind and maybe thought we could do that for you, but that decision will be yours to weigh in. it will do well with either.
Hey Tony - I think the OP is referring to the 'Sun Power' (UL listed) modules which are different than the 'Sun' (non-UL) modules Sunelec sells.
The Suns (non-UL) are re-labeled Evergreens BTW.
The current production SunPower panels (at least the 210 watt version pdf spec.) are UL and CSA (probably listed--spec. does not say) for both Canada and US.
My mistake,, but now you have me all confused. I didn't realize that there were two different manufacturers! So is it the Sun (from Sun electric in Fla) or Sun Power that is positive grounded?
sunpower is positive ground.
IMHO, unless there is a significant savings for going with Sunpower, buy the Evergreens. My reasons
At some point, something may fail in your system, I dont know what it will be or if you will be the owner, but if you bring in a third party to work on it, its a heck of a lot easier to work on a standard configuration and currently positive ground is not standard. (I used to have a positive ground car and despite the warning labels, it was real easy to almost accidently hook up battery cables in reverse!)
Evergreens are built in the US and are based in the US, if you have problems in the long run with the panels, its a heck of a lot easier to call Marlborough Mass than somewhere in China.
Thanks All, appreciate the feedback. No decision yet, but I am certainly leaning toward the Evergreens.
Shouldn't that say 6 dollars a watt and not 6 dollars a kilowatt?
Probably 6 kilo-dollars per kilo-watt...
Made the jump. Signed up for an 8.2KW system. 39 Evergreen 210 Panels. Let the paper work begin! Thanks for the help.