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  • SolarTDI
    Junior Member
    • Apr 2011
    • 3

    #1

    NEW HERE, How much batteries do i need for 2000w consumption.

    Hello, i think someone could help me here,

    So, i want to get 2kw or 2.5kw for few hours (2 or 3) using solar panles and wind combined,

    So if i use 12V 150Ah, how much batteries will it take, and lets say if i have 4 pcs x 12v 150ah if that will be enough or no?

    And how much time will i get if i use 4 x 12v 150ah if the consumption is 2kw?

    I hope someone will helo me,

    Thank you,
  • Sunking
    Solar Fanatic
    • Feb 2010
    • 23301

    #2
    Originally posted by SolarTDI
    So, i want to get 2kw or 2.5kw for few hours (2 or 3) using solar panles and wind combined,
    You need to nail down the usage better than that as the range you have given is 4 Kwh to 7.5 Kwh. That is almost a 100% difference

    Originally posted by SolarTDI
    So if i use 12V 150Ah, how much batteries will it take, and lets say if i have 4 pcs x 12v 150ah if that will be enough or no?
    This is where the news gets really bad for you.

    At 2000 watt load 4-12 volt @ 150 AH batteries to 50% DOD will last about 30 minutes at best. With a 2500 watt load about 15 to 20 minutes if you are lucky.
    MSEE, PE

    Comment

    • SolarTDI
      Junior Member
      • Apr 2011
      • 3

      #3
      Originally posted by Sunking
      You need to nail down the usage better than that as the range you have given is 4 Kwh to 7.5 Kwh. That is almost a 100% difference

      This is where the news gets really bad for you.

      At 2000 watt load 4-12 volt @ 150 AH batteries to 50% DOD will last about 30 minutes at best. With a 2500 watt load about 15 to 20 minutes if you are lucky.

      Tnx a lot for your fast answer, nail down the usage 2h and 30 min., i need 2kw of power, i have some proces for which i need power for that time.

      So i was planing to put 4x 150ah batteries, but like you sad thats very little, so what do you think how many batteries of 150ah i should put so i will get my plan working?

      And could you tell me a formula or something, for example 1000w how many Ah or something like that.


      Really thank you a lot

      Comment

      • Mike90250
        Moderator
        • May 2009
        • 16020

        #4
        Watts = Volt x Amp
        Watt Hours = Watts x (time in hours, 1.5, 6, 18)

        so 30 watts for 2 hours would be 60Wh

        7.5KW for 3 hours = 22,500 Wh or 22.5 KWh


        But we really need a firm estimate of your load in watts, and time, to properly size a battery bank and inverter for it. I do know it will NOT be a 12V system, but either 24 or 48V.

        Also, knowing how often this backup comes into action is useful. 1 x a week, we can allow for deeper discharge, but daily, we have to limit to shallow discharge to prevent early battery death.
        Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
        || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
        || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

        solar: http://tinyurl.com/LMR-Solar
        gen: http://tinyurl.com/LMR-Lister

        Comment

        • Naptown
          Solar Fanatic
          • Feb 2011
          • 6880

          #5
          Sounds like you are looking at 24-28 batteries perhaps more.
          Can't you just plug it in to the grid?
          NABCEP certified Technical Sales Professional

          [URL="http://www.solarpaneltalk.com/showthread.php?5334-Solar-Off-Grid-Battery-Design"]http://www.solarpaneltalk.com/showth...Battery-Design[/URL]

          [URL]http://www.calculator.net/voltage-drop-calculator.html[/URL] (Voltage drop Calculator among others)

          [URL="http://www.gaisma.com"]www.gaisma.com[/URL]

          Comment

          • Sunking
            Solar Fanatic
            • Feb 2010
            • 23301

            #6
            Originally posted by SolarTDI
            i need 2kw of power,
            Completely meaningless statement. How long do you need 2 Kw? For 1 second, or 5 hours per day?

            Watt Hours = Watts x Hours.

            1 second = .000277 hours

            2000 watts x 1 second = 2000 watts x .000277 hours = .000,000,139 watt hours.

            2000 watts x 5 hours = 10,000 watt hours.

            So your answer is somewhere between 0 and 10,000. What I can tell you from the info you have provided, you have not even made a down payment to spark my interest.

            Have a nice day
            MSEE, PE

            Comment

            • SolarTDI
              Junior Member
              • Apr 2011
              • 3

              #7
              Originally posted by Sunking
              Completely meaningless statement. How long do you need 2 Kw? For 1 second, or 5 hours per day?

              Watt Hours = Watts x Hours.

              1 second = .000277 hours

              2000 watts x 1 second = 2000 watts x .000277 hours = .000,000,139 watt hours.

              2000 watts x 5 hours = 10,000 watt hours.

              So your answer is somewhere between 0 and 10,000. What I can tell you from the info you have provided, you have not even made a down payment to spark my interest.

              Have a nice day


              Hahaha you are right tottaly, but, you should know that i am beginer )) So dont judge me I`m gona get more and more info and then im gona ask a new more professional question Thank you all for your answers

              Comment

              • Sunking
                Solar Fanatic
                • Feb 2010
                • 23301

                #8
                Originally posted by SolarTDI
                Hahaha you are right tottaly, but, you should know that i am beginer )) So dont judge me
                I am not judging you, poking fun at you.
                MSEE, PE

                Comment

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