Same Chinese panels and branding?

verdigo
verdigo Solar Expert Posts: 428 ✭✭
in Solar Product Reviews & Opinions #1
I have purchased three grape solar 280 watt panels from Home Depot. I had planned to buy one more. Now I am looking at a Trina 290 watt panel that has exactly the same dimensions as the grape panels and really close on the electrical characteristics for a little more than half the price. Home Depot has free shipping but I am pretty sure it is built into the price. I would like to buy the next 5 panels (Trina) all at once to take advantage of the shipping discount buying more than one at a time. The question is, is it ok to mix these into the same string or array? I suspect they are the same manufacturer.

Dennis
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Same Chinese panels and branding?

    What are the differences in panel specifications? There must be some, either in Vmp or Imp or both, to account for the 10 Watt rating difference. I suspect that it will not be enough to matter, though, especially if the difference is all in Imp and you place the new panels (or strings thereof) in parallel with the old.
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #3
    Re: Same Chinese panels and branding?

    The grape solar VMP is 35.8 volts IMP 7.82 amps. The Trina panel's VMP is 36.4 and IMP 7.97 amps. I would be mixing one Grape and one Trina in one string.
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #4
    Re: Same Chinese panels and branding?

    3 grapes and 5 trina will not work as you describe, it may be better to have 2 array one of each brand and then combine their output.
     
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #5
    Re: Same Chinese panels and branding?
    westbranch wrote: »
    3 grapes and 5 trina will not work as you describe, it may be better to have 2 array one of each brand and then combine their output.
    So It would be better to by another Grape panel and the rest Trina. There shouldn't be any problems with all on one Classic 150 as long as the strings are matched?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: Same Chinese panels and branding?

    In your original proposal you would have three strings of one Grape and one Trina and one string of two Trinas. The Vmp and Imp differences are very small, so it would work at the expense of a bit of power. The mixed strings would be 72.2 Vmp @ 7.82 Imp or 564 Watts and the "all Trina" string would be 72.8 Vmp @ 7.97 Imp or 580 Watts.

    With a string Vmp difference of 0.6 Volts I don't think the loss would be serious. Your MPPT controller is going to pick its own best V and I according to what it thinks is right and may never go for the actual panel rating numbers.
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #7
    Re: Same Chinese panels and branding?
    Cariboocoot wrote: »

    With a string Vmp difference of 0.6 Volts I don't think the loss would be serious. Your MPPT controller is going to pick its own best V and I according to what it thinks is right and may never go for the actual panel rating numbers.

    This would work better for me as the difference in the prices of one panel would be a good chunk of the shipping cost of the five Trina panels.
    Thanks for the good info. This is what I had hoped for.
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