Forum Topic

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.
  • Post deleted #12212110
  • 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
  • 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.

    May required voltage range at ampere rating naman si Inverter at kung nameet niya yun ay gagana siya. Wala naman pagkakaiba ang portable generator sa kuryente na galing sa Meralco. Generator din naman yan malalaki lang. Kaya nga kahit galing sa Meralco kuryente natin ay yung iba gumagamit pa rin ng AVR.
  • Wala naman pagkakaiba ang portable generator sa kuryente na galing sa Meralco.


    My research on the subject says otherwise.

    Are you telling me that you can use a limiter with a regular grid-tie inverter with no grid, only powered by a regular portable generator and:
    A) Backfeeding to the generator will not occur; and
    B) Inverter operation will not be interrupted?

    If so, can you indicate an exisiting installation or any other reputable source that confirms this? Naguguluhan nanaman ako akala ko settled na na hindi pwede.

    -- edited by rancor2023 on Apr 28 2019, 11:36 PM
  • A) Backfeeding to the generator will not occur

    Nangyayari ang back feeding pag may demand, sa case ng generator ay wala dahil parehas na producer, idle na lang siya.
    compare to meralco may backfeeding kasi yung kapitbahay mo or kahit sino na nakakabit sa grid ay gumagamit sila. which is advantage sa power plant kasi mababawasan load niya, iwas stress.
    B) Inverter operation will not be interrupted?
    unless kung unstable ang generator mo.
    If so, can you indicate an exisiting installation or any other reputable source that confirms this? Naguguluhan nanaman ako akala ko settled na na hindi pwede.

    as i said parehas lang ang meralco sa generator sa laki lang ng system magkaiba. sorry wala pa ako nakikita na ganitong system, minsan lang napag usapan namin yung proposed proj sa Palawan. existing kasi nila ay Generator sa isang community at gusto dagdagan ng Solar. May napanood din ako na video noong nangyari yung typhoon Irma na saktong sakto sa binabanggit mo.
  • without solar panel



    with solar panel

  • Nangyayari ang back feeding pag may demand, sa case ng generator ay wala dahil parehas na producer, idle na lang siya.


    So yun na nga, kung may limiter walang backfeed? Even slightly, in terms of millisecond spikes? I understand na pag walang demand idle ang generator and that the excess power generated is turned to heat, but when it comes to grid-tie solar, I have first-hand experience with slight reversal of the meter nung may temporary limiter pa ako. And my limiter was specifically made for my inverter. Yung ganoong spike is what is deadly to regular portable generators as I've understood.

    unless kung unstable ang generator mo


    So tama nga yung research ko na unless mamahaling generator ang gamit (the type which provides stable frequencies and can handle sudden incoming spikes), the scenario I posited in my last few posts is impossible, or at the very least extremely unsafe.

    My point in raising this scenario is to provide info for people who think of Meralco and portable generators as interchangeable in terms of blackouts. Kasi that is one of my problems as a grid-tie user. May araw nga, wala namang Meralco, e di brownout pa rin. Kaysa sa battery ako maginvest, sa generator na lang.

    Like I've said, wala kasi akong nakikita sa common forums that discuss this scenario. Even abroad, some obscure African forum pa ang nagprovide ng info re: the possibility of this setup. So unless there is a documented setup of this kind, I am inclined to believe that unless your generator is tailor-made for this setup, or at least provides stable frequencies and can handle sudden incoming spikes, and/or your inverter is 100% one-way when operating with a limiter, the interchangeability of grid and portable generators is not applicable when used in conjunction with a grid-tie solar setup.
  • So yun na nga, kung may limiter walang backfeed?

    kung sa generator talaga sir naka connect walang back feed, may limiter yan o wala. unless kung may iba na nakakabit sa generator mo doon na mangyayari ang backfeed pag mas malaki ang power galing sa solar mo kumpara sa ginagamit. at yung back feed mo ay pupunta sa isang user.
  • doon na mangyayari ang backfeed pag mas malaki ang power galing sa solar mo kumpara sa ginagamit


    By the nature of solar and inconsistent residential demand, hindi constant ang power requirement and power harvest. May time na mas mataas ang solar. So yes, backfeeding will occur as per your explanation, correct?

    Hindi ata tayo nagkakaintindihan, paki refer na lang dun sa previous scenario ko just to be sure. I'm trying to find out kung pwede akong gumamit ng generator para magamit ang grid-tie ko during blackouts. My research says no, unless the equipment is rated for such operation (specifically the generator).

    at yung back feed mo ay pupunta sa isang user


    Hindi pwede pumunta sa grid yung backfeed during a brownout dahil obviously ididisconnect ko yung grid. I am not an electrical engineer but even I know that plugging a generator into the grid would cause catastrophic failure in the involved equipment when the grid goes up. Not to mention the possibility of killing a lineman somewhere if the grid is down for repairs. Kaya nga may anti-islanding si inverter, e.
  • @all

    I'm not trying to be a know-it-all (and I hope I don't sound condescending) but I am merely trying to share (and confirm with knowledgeable people here) the research I did because wala akong makitang info in common websites so hopefully dun sa mga future na magiisip kung possible tong scenario na ito, makatulong ako.

    Pero it's tiring to have to repeat myself again and again, especially when the responses are taking bits and pieces from my posts and explaining it separately instead of the whole, as if I don't know most of the basic stuff despite having shared a lot of information that would at the very least make me not a solar noob.

    Maybe it's my fault for not wording things correctly. In which case, I feel it best to avoid further confusion on the matter and just end the discussion, leave it as it is, and hopefully some person in the future would find this and understand the point I was trying to put forward about not being able to use your common portable generator as a grid substitute for your grid-tie, even if you have a limiter installed.

    With that, I also bid this thread goodbye and let actual electric/solar experts retake the role of answering questions and sharing their experiences. This thread helped me understand a lot before I even had the funds to take my research into solar seriously. I hope it continues to do the same for those who will stumble upon it in the future.
  • sharing: 1 year after solar installation.
    4.8kw grid tie system.. (60% )maximized lang kasi not netmetered allowed at our old house. and only consuming mostly 2 to 3kw lang during the day. used mostly for a 2kw bitcoin mining rig during the day + 2 1hp aircons + ref/tv..etc

    with power generation based on consumed only: roi is 60k pesos for 1 year

    diy solar investment (150k total for panels + inverter and build cost) , im halfway ROI.

    if i factor earning in btc for 1 year, bawi na.

    today's graph below where fluctuations are mainly aircon during the night and other appliances, the 2kw fix load is due to timer'd 2kw btc asic mining. not very profitable only 6k pesos per month at todays rate, but it started at around 12k pesos per month last year. and i only run it during the day thus half the earninng only.




    -- edited by olhr on May 08 2019, 12:11 PM
  • mga sir goodafternoon..question lng po kung meron kayo alam na gumagawa ng off grid inverter? may battery voltage reading pero wla na output na 220V sa plug ng inverter ang problem. Thanks in advance.
  • ^nacheck mna kung meron syang fuse, baka putol lang? try mo mgpost sa SPP sa FB (Solar Power Philippines).
  • Yes sir dodick fuse una ko na check lahat buo pa walang putol..talagang un sa nag output ng 220 na side ung sira.cge sir checkin ko dyan.

    sa ibang members po dito baka po meron pa kayo iba masasuggest or marerecommend if nagpagawa na kayo ng inverter noon. Tnx po in advance
  • Taga saan ka ba sir? meron ako kakilala pero Cavite
  • So tama nga yung research ko na unless mamahaling generator ang gamit (the type which provides stable frequencies and can handle sudden incoming spikes), the scenario I posited in my last few posts is impossible, or at the very least extremely unsafe.
    I clear ko lang ano yung backfeed na sinasabi mo... iyon ba ay ang pagsalubong ng dalawang source mo at inturn ay sasabog siya?

    Ganito kasi yun

    1. Generator - madami spikes ang power generated niya at di siya identical sa Meralco kaya kukurap ang bulb.

    2. Grid tie inverter - nag si sync siya sa grid voltage

    ang gusto mo mangyari eh pag may brownout eh pagaganahin mo si generator para mag produce ng power si grid tie.

    I offer 1 simple solution without the use of expensive generators and fuel. Instead of buying a generator buy another inverter with a no batt, no grid feature which means it can operate as long as there is sunlight. Unfortunately yung stocks namin with 4x surge ay this coming July pa. Pm me for info.
  • Yes sir dodick fuse una ko na check lahat buo pa walang putol..talagang un sa nag output ng 220 na side ung sira.cge sir checkin ko dyan.

    sa ibang members po dito baka po meron pa kayo iba masasuggest or marerecommend if nagpagawa na kayo ng inverter noon. Tnx po in advance
    Wala pong special sa loob ng inverter kaya any good electronic technician can repair it meaning kahit yung nag rerepair ng TV eh kaya yan ayusin.
  • Wala pong special sa loob ng inverter kaya any good electronic technician can repair it meaning kahit yung nag rerepair ng TV eh kaya yan ayusin.

    yes true madali sya o kaya irepair ng technician, ang problema nga lang like ung TBE lahat ng mosfet nya sinadyang burahin ung code kya hirap mgpalit basta2. pro sa ngayon mdali na lang kc readily available na ung parts sa suking online tindahan hehe....

    mga master, possible po ba gmitin ung off grid then saksakan pa ng gti while off grid sya (no DU)? thanks.