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Unified Solar Panels and Controllers Thread (FAQs, DIY Help)

  • 1. It won't work at all if you try to connect it directly to the PSU. You need an inverter to convert it to 220v AC to power the PSU, or replace the PSU with one that runs on DC voltage. I'm going to assume that you'll be using a 12v battery.

    2. How long it will last depends on a lot of factors:
    -- battery capacity (in ampere-hours)

    -- actual current draw of the PC (it will draw much more current when fully loaded compared to idle)

    -- conversion efficiency of the inverter and PSU (if you're using an inverter), or the DC PSU. The second option is generally more efficient as only one stage of power conversion (DC-DC) is done.

    Using an inverter is less efficient because there are power losses on each stage (DC--> AC then AC --> DC) of conversion. Note that this is how an Uninterruptible Power Supply (UPS) works, so it's possible to make a "guesstimate" of battery runtime by comparing your battery capacity to that of what's inside a particular UPS.
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  • before you invest in solar system, bili ka muna ng solar fan sa lazada 12 volts dc yan at may kasamang adapter pang ac outlet, wattage nya pag sinukat 15watts lang, so pag may solar ka na pwede na tumagal ang oras ng gamit mo sa fan bago maubos ang charge ng battery
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  • This is the part that baffles me. Assuming the generator is tapped into the main breaker going into the house but is disconnected from the grid, how is the inverter/limiter able to tell that it is not grid power and prevent throttling down production to prevent backfeeding?
    Won't work for the simple reason that a limiter has a delay before turning off and turning on of the inverter so the problem is if you have an ATS or relay that is faster than the limiter there is always the chance that Solar, grid and generator power will meet sometime and it might not be a very good scenario depending upon the equipments used.
  • @rancor, about "Assuming the generator is tapped into the main breaker going into the house but is disconnected from the grid, how is the inverter/limiter able to tell that it is not grid power and prevent throttling down production to prevent backfeeding?"

    the generator is AC thus direction of voltage sinusoidaly alternating from positive and negative, the inverter knows if its backfeeding if the "amperage" current is more in the direction of the load than the source. the inverter/limiter doesnt know if the AC source is meralco or generator. if you think about water flow, basically the generator is a source of water and the inveter as a the source also. what the limiter monitors is both the water comming from the inveter and the water comming from meralco, the limiter will only allow water from meralco to flow if the load requires more than the inveter is able to give thus will be supplimented by the meralco source.
  • My scenario never involved an ATS or a relay.

    Also:

    the inverter/limiter doesnt know if the AC source is meralco or generator.


    This is what confused me as to why an off-grid generator-coupled grid-tie inverter with limiter would not work.

    But like I said, I later found out that the inverter actually DOES know if the AC source is grid (clean) or generator because of the anti-islanding features that detect minute changes in the frequency and voltage of the source when the rpm of the generator changes due to demand.

    The only possible way to operate an off-grid generator-coupled grid-tie inverter with limiter is to make sure your generator produces "clean" power (one that maintains frequency and voltage despite demand changes). Like I mentioned, this does not mean your regular residential generator.

    -- edited by rancor2023 on Apr 03 2019, 02:34 AM
  • For further clarification, this is the scenario:

    1) May grid-tie with limiter ako.
    2) Hindi nagbabackfeed si inverter kay grid dahil kay limiter.
    3) Nagblackout.
    4) Pinatay ko yung service disconnect para walang papasok na kuryente kung biglang bumalik.
    5) Kinabit ko si generator after ng service disconnect papasok ng bahay.
    6) In essence, may "grid" na. Gagana na dapat si grid-tie.
    7) Dahil kay limiter, walang backfeed kay generator.

    Sa unang tingin, tama.

    Pero hindi pala pwede dahil sa anti-islanding features ni inverter kung saan nadedetect niya yung frequency and voltage change ng "grid" kapag bumabagal o bumibilis yung takbo ng makina ng generator depende sa demand.

    In short, matalino si inverter. Para maloko mo siya na may pekeng "grid" kailangan yung generator mo hindi pipitsugin. Yung tipong ginagamit sa mga sensitive electronic equipment na walang frequency o voltage change bumaba man o tumaas ang demand.
  • sino po dito taga las pinas area malapit sa sm center or vista mall na pwede mag mount ng solar panel ko na 150w sa bubong ko. please see pic. matagal na po yang pic na yan kaya hindi ko na mahanap yung gumagawa nung bubong. kahit diy lang po para lang makabit yung panel




    -- edited by michelle_dyane on Apr 04 2019, 12:38 PM
  • @Michelle Kapit bahay lang tayo mukhang iisang subdiv tayo, PM Sent

    -- edited by cordille on Apr 04 2019, 08:28 PM