Anyone Heard of Sun Panels? Sin Wave?

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System
System Posts: 2,511 admin
in General Solar Power Topics #1
Im looking at setting up a 6kW off grid system, and i found some really good prices. However, when i searched for these panels, there is no data sheets, records, etc., just forums on them. The website i found them on is sunelec.com . Why are these panels so cheap? Am i better off buying a name brand like Suntech, Trina, Evergreen, or Kyocera. I just hate the idea of spending all this money on panels that I have no intention of tying into the grid, yet the people there told me that i was just paying for the UL certificate. Is this true? Has anyone actually bought these panels ever or dealt with this website. Second, Inverters: I am looking at the XW6048, but is there a noticable difference in the pure and modified sine wave?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Anyone Heard of Sun Panels? Sin Wave?

    There are at least two different manufacturers who use the term "sun" in their panel name. If you search this forum I'm sure there's info about Sun Electric panels. Unfortunately I think those are the "positive ground" ones which aren't the easiest things in the world to match up to equipment (it can be done). Bill will know for sure.

    As for inverters, all grid-tie inverters are sine wave; MSW won't synch to grid power.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #3
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    Re: Anyone Heard of Sun Panels? Sin Wave?

    I am typing this on a phone, so it is hard to copy links.

    Enter the following into Google and read the first link or so on this forum:

    sunpower positive ground site:wind-sun.com

    And yes, there is a big difference between msw and tsw inverters. Many smaller wall transformers, electronic power supplies, heavily used/high duty cycle motors, etc. can over heat. Motors may use upwards of 20% more power, some appliances with timers may not time correctly, and some devices may buzz.

    Because tsw inverters are so expensive, some folks get a smaller tsw inverter for small critical loads and a cheaper large msw inverter for power tools.

    Roughly, 80% devices will work ok on msw and 10% may overheat/have a shorter life--The problem is knowing which is which.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • System2
    System2 Posts: 6,290 admin
    #4
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    Re: Anyone Heard of Sun Panels? Sin Wave?

    Bill and Caribou, thanks. Quick question. At the risk of sounding ignorant, what exactly makes these panels positive ground? And more important, what is positive grounding. Its my understanding that you have a positive and negative lead and that you ground the frame on the panel. How is this different and what is positive grounding? Thanks in advance. I got this out of the post i searched for. Is this correct:
    "it just requires running a separate wire to the ground." in a system where earth is not available, is to wire instead to the conducting "frame" of the system
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  • System2
    System2 Posts: 6,290 admin
    #5
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    Re: Anyone Heard of Sun Panels? Sin Wave?

    Apologies but i did read some of the posts but im not really clear. I read your post Bill on "When positive ground is used in PV" and it makes sense, but im still confused on the act of the grounding. It makes sense why you use it, but i just dont get how. Does this post by you mean that you ground the positive battery bus to earth ground, and the rest of the system remains ungrounded?

    A positive ground can be done (just ground the positive battery bus--and nowhere else) and check that all of your equipment (charge controller, wiring, downstream DC equipment, etc.) does not tie negative battery to chassis/safety ground.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #6
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    Re: Anyone Heard of Sun Panels? Sin Wave?

    Yes, you are correct.

    Positive ground actually has some advantages--but because most other off grid DC equipment and users assume negative grounding--it can be a huge pain to build out a positive grounded system and not end up with a plus/minus short somewhere.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Anyone Heard of Sun Panels? Sin Wave?

    Sorry: I didn't read the first post right. I though you said "grid tie" not "off grid"? Maybe I'm answering too many questions from too many directions and getting more confused than usual. :p

    From a practical point of view you only have to know it can be somewhat problematic to connect the positive ground panels to certain controllers. And if you can't get specs on the panels you're thinking of buying ... don't buy them. Not just those ones specifically; there are many "off beat" panels/products available out there which often come with "bargain" price tags and turn out to be more trouble than they're worth. Fine if you're experimenting and/or know exactly what you're doing, but potentially frustrating and expensive nonetheless. Many an inexpensive component has ended up being pricey after it burns up. Sometimes paying for "just UL listing" isn't a bad idea.

    If you need reliable power from this system, don't be penny wise and pound foolish.
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