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MrWizard's avatar
MrWizard
Moderator
Jun 07, 2015

Adding More Solar Panels

i'm looking at Amazon at the Windy Nation 100w
and the Eco Worthy 100w panel

both are 100w, specs are close 17.4 working volts 5.75 max working amps
versus 17.9 working volts and 5.56 working amps

the price difference is $18 per panel, so it is NOT the deciding factor, quality and performance are my concern
either should be compatible with the uni-solar but the windy nation 17.4v is the closest

i want to purchase (3) panels
replace (3) of my 40w uni-solar with (3) 100w poly panels
i will gain 180w bring my system to 685w total

the Xantrex C-40 can handle it, specs call for a peak of 85 amps and then it goes into current limiting and/or disconnect to prevent damage to controller

started the day with good overnight shore charged batteries
i'm running a solar charge test today and so far peak is 18+ peak amps with an avg of 16.28amps at 13.57v output at controller, with loads running, PC, fans, and fridge cycling
looking to see what max total accumulation is for the day from the existing panels
one panel drivers side far front, has a damaged cell
i have not disconnected it for a diagnostic yet, i'm sure it is a contributing factor, but i'm not sure how much of a factor
i will replace it with one of the good panels that i swap out with the new ones

i'm looking at this partial replacement, because of size & placement and i need too keep some room on the roof for repair access, vents A/C etc..

any experience or comments on the two panels choices , appreciated

37 Replies

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  • BFL13's avatar
    BFL13
    Explorer II
    Jun 08, 2015
    Yes that is a Solar30 which is a good controller. Not sure Mr Wiz ever gets to where the float voltage matters with all his mix of gen time and solar and the 120v fridge.
  • grizzzman's avatar
    grizzzman
    Explorer
    Jun 08, 2015
    MrWizard wrote:
    unisolar voc 23.8 , working volts is 16.5v
    a bit lower than i remembered it
    lots of diodes in the unisolar panels, it should be safe to connect them to the windy nation 17.4 working volts
    but i might connect them to a separate controller, and parallel the outputs to the batteries, just set the controllers for the same bulk and float voltages

    i'm looking at this controller
    windy nation 30amp user adjustable



    That unit is a solar30 controller it only has one setting. You would need to set it to your bulk then when when you wanted to float change the setting. Kinda a pain realy.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Jun 07, 2015
    Hi,

    Use the panel that is closest to what you already have. Or use a 2nd controller.
  • MrWizard's avatar
    MrWizard
    Moderator
    Jun 07, 2015
    unisolar voc 23.8 , working volts is 16.5v
    a bit lower than i remembered it
    lots of diodes in the unisolar panels, it should be safe to connect them to the windy nation 17.4 working volts
    but i might connect them to a separate controller, and parallel the outputs to the batteries, just set the controllers for the same bulk and float voltages

    i'm looking at this controller
    windy nation 30amp user adjustable

  • BFL13's avatar
    BFL13
    Explorer II
    Jun 07, 2015
    With PWM all you care about is amps. Power is MPPT stuff.

    So the comparison is Voc 22.41, Isc 6.2 with the EW vs 21.6 and 6.32 with the WN.

    IMO the WN wins by itself with the 6.32a, BUT the job is to be in parallel with the existing panels so the voltage match could matter somewhat, where 22.41 and 21.6 are the numbers to compare with the Voc of the remaining existing array.

    I suppose depending on the wiring involved in the new arrangement, line losses will vary and make any fine-tuning panel voltage matching hard to realize?

    Sounds like the idea would be to remove the old panels first, then get the Voc of the existing remaining array and then do the match? After it is all together, the new array Voc could be compared with the old to see how close you got. (Assuming that will even matter to the big picture)
  • grizzzman's avatar
    grizzzman
    Explorer
    Jun 07, 2015
    MrWizard wrote:
    i'm looking at Amazon at the Windy Nation 100w
    and the Eco Worthy 100w panel

    both are 100w, specs are close 17.4 working volts 5.75 max working amps
    versus 17.9 working volts and 5.56 working amps

    the price difference is $18 per panel, so it is NOT the deciding factor, quality and performance are my concern
    either should be compatible with the uni-solar but the windy nation 17.4v is the closest

    i want to purchase (3) panels
    replace (3) of my 40w uni-solar with (3) 100w poly panels
    i will gain 180w bring my system to 685w total

    the Xantrex C-40 can handle it, specs call for a peak of 85 amps and then it goes into current limiting and/or disconnect to prevent damage to controller

    started the day with good overnight shore charged batteries
    i'm running a solar charge test today and so far peak is 18+ peak amps with an avg of 16.28amps at 13.57v output at controller, with loads running, PC, fans, and fridge cycling
    looking to see what max total accumulation is for the day from the existing panels
    one panel drivers side far front, has a damaged cell
    i have not disconnected it for a diagnostic yet, i'm sure it is a contributing factor, but i'm not sure how much of a factor
    i will replace it with one of the good panels that i swap out with the new ones

    i'm looking at this partial replacement, because of size & placement and i need too keep some room on the roof for repair access, vents A/C etc..

    any experience or comments on the two panels choices , appreciated



    Im running the poly windy nation panels. It will produce a bit more amps for the money. Well as long as your wiring is sized correctly. Check windy nations ebay store likely for the best price. PWM amps is what counts.

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