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  • #31
    Originally posted by Sunking View Post
    FWIW, for as long as I have been around here, the MODS are not going to pull the plug on you for a passionate spirited debate. If they did, I would have been gone long ago.
    Spirited debate is even a good thing.

    Some fools come along, start posting ignorant trash and arguing - they are the ones that get bumped off.

    Anytime a poster is trying to post opinions that are unsafe or generally misleading for our members they get the little push as well.
    [SIGPIC][/SIGPIC]

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    • #32
      Hi Sunking,
      Thanks for the words of wisdom and i will keep looking for the humor, (i have read hundreds of your post, and it still alludes mee!!) I have shipped three types of panels, solsonica 213w, Eclipse 210w and the bulk being Zenpower 200w, the first two had the vmp listed on the panels not on the Zenpower, i have managed to find a pdf file for one of their 200w and that list's a umpp of 26.24.
      I have another question i hope you can help with, i will post it now.
      P.S I will try not to be to ignorant or foolish Russ.

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      • #33
        Originally posted by Gambia river lodge View Post
        I have shipped three types of panels, solsonica 213w, Eclipse 210w and the bulk being Zenpower 200w, the first two had the vmp listed on the panels not on the Zenpower, i have managed to find a pdf file for one of their 200w and that list's a umpp of 26.24.
        OK not trying to scare you, but this raises RED FLAGS of mixing panels. Can you list the specs of each of the three panels. What we or I need to know is:

        Voc
        Vmp
        Imp
        Isc
        MSEE, PE

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        • #34
          Do not worry SK, no mixing will be involved, i have 18 x Solsonica, 18 x Eclipse and 64 x zenpower along with approx 60 12v panels of varing power outputs, still no quite sure how to configure all of them but, i have the bulk of them on seperate arrays with controllers and batteries, the other will be sorted in time when i am more confident of what exactly happens when running the larger arrays for 12 months.
          thanks for your concern. Mike.

          Comment


          • #35
            Originally posted by Gambia river lodge View Post
            Do not worry SK, no mixing will be involved,
            I do not think you understand. Unless all those panels are matched up closely, you have a problem (puzzle) to solve.
            Let me give you a real life example. Let's say I have two different models of panels. A 100 watt standard 12 volt (36 cell) panel, and a 200 watt standard grid tied panel (54 cells)

            If you were to wire them in parallel you would have a Vmp of 17 volts @ Imp of 13.28 amps. That works out to 225 watts

            If you were to wire them in series you have a Vmp of 44 volts @ Imp of 5.88 amps. That works out to 258 watts.

            There is no possible way to wire the two panels to obtain the 300 watts. Only option is to put them in separate systems on there own charge controller serving a common battery.
            MSEE, PE

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            • #36
              Hi,
              Yes SK i am aware that any variation of more than 10% in volts or current is effectively pointless in series or parallel connection, however you have raised a couple of questions for me in your example.
              How have you come to the VMP figures of 17v and 27v for the two respective panels, if i use the understanding of 0.5v per cell you get 18v and 27v, plus why is there such a big difference in the vmp of the nominal panel voltage, respectively, 5v over for 12v and only 3v for 24v, (i think its resistance, but not sure?)
              Now i am fine with 10% difference of each panel however, how does this affect a mppt controller.
              example;
              4 x 60w @ 12v
              4 x 80w @ 12v
              4 x 100w @12v
              4 x 120w @12v
              can they be wired into one mppt contrller without any great losses ?

              Comment


              • #37
                Originally posted by Gambia river lodge View Post
                How have you come to the VMP figures of 17v and 27v for the two respective panels, if i use the understanding of 0.5v per cell you get 18v and 27v, plus why is there such a big difference in the vmp of the nominal panel voltage, respectively, 5v over for 12v and only 3v for 24v,
                Yes approx .5 volts per cell but current is a unknown factor due to the size of the cells.

                You can easily but 12 volt panels in wattage ranges of 5 watts to 180 watts. They will all have similar Voc and Vmp of 22 volts and 17 volt respectively, but current will range from .3 amps to 10.6 amps which means they can only be configured in parallel operation.

                As for the 27 volt panel was an example of a grid tied panel of 54 cells. Panels made for battery systems are in multiples of 36 cells. A 12 volt panel has 36 cells, a 24 volt panel has 72 cells. Grid tied comes in at a low of 54 cells and up to around 80 cells. Anything larger in cell count becomes structurally unstable.

                So now your problem becomes how are you going to group your panels to get 48 volts without sacrificing a lot of potential power? With battery panels you are kind of stuck with parallel arrangement of like panels. You can series 4 of th e12 volt panels to get 48 volt battery, but if you stick a low wattage panel in the series string you are limited to the lowest current in the series string.

                Again I warn you to determine how many watt hours you need in a day and design around that. Otherwise you might very likely have some very nasty unpleasant expensive lessons ahead of you. Batteries are very unforgiving, and if you abuse them, they will punish you severely. No questions asked or warnings. Just darkness and cursing the battery Gods.
                Last edited by Mike90250; 01-30-2012, 05:48 PM. Reason: added emphais
                MSEE, PE

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                • #38
                  Originally posted by Gambia river lodge View Post
                  4 x 60w @ 12v
                  4 x 80w @ 12v
                  4 x 100w @12v
                  4 x 120w @12v
                  can they be wired into one mppt contrller without any great losses ?

                  Yes but that is a far cry from the original 3200 watts you started with?

                  You would take 4 of the same panels and wire them in series for a 48 volt system, and repeat for the remaining 3 like panels and make them all parallel. That would yield you around 68 volts Vmp @ 21 amps Imp or 1440 watts. On the output will get you around 30 amps on a MPPT controller.
                  MSEE, PE

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                  • #39
                    Ok SK,
                    I am beging to know you now, i am not sure if you do this! or if it helps you, But it would certainly help me !! make notes (mental if poss) about some of the people on the forum, especially the dumb and stupid "newbies" as i am one of them.
                    However, if you really need me to list all that i am doing or the equipment i have every time i post, OR REPLY i can do so, OR i can write everything twice so the bits you miss the first time you may get (no gaurantees now!) the second time.

                    I Have approx 160 panels (would you like to know how i got them?) the bulk of which i will be building three array's with over the next two months in Gambia, they are;
                    18 x solsonica 213w 18 x Eclipse 210w and 64 Zenpower 200w, i also have 10x mitsibushi 180w (i think they are, in my store out there) and approx 60-80 12v panels of different sizes. 6 x pcm5048 mppt 40a charge and 4 x pcm6048 50a charge controllers.
                    Now, after you fine EDUCATION, i have redesinged my 3 main arrays in as follows;
                    Solsonica S3P4 to pcm5048 and S2P3 to pcm 6048 to 24 x 2v 440ah batts;
                    the same for the Eclipse and muliples for the Zenpower.
                    Ok before you jump!! i know i am loosing 100w on the S2P3 set up, however i have factured in that 213w are somewhat labratory conditions and in real life they have a 20-25% reduced capacity, max current ok, max volts ok, i can live with loosing 100w but i think i loose that anyway yes!!
                    Again hold on!! I know the AH of the batts is two low however, if you wouls like to read my other 'post' (i did say i was a newbie, i only have two) i have explained some of the reason for that, and it will be adjusted as an when i can be sure of what is happening and the maintence is in place.
                    Now for your last post and the one before, you forgot to highlight ( i don't know how highlight yet) EXAMPLE; and by the way, many thanks for the answer, i will get to these later in the year, but more seriously, you said about working out my watthours, believe me i wish i could but in a place like africa that just simply is not possible, and there are hundreds like me there who are in the same boat, just a quick example, ten years ago i built a solar oven and cooked ten chickens, they would not eat them until they had 1 min over a flame (devil work), that is my name there now Devilman, if an engine starts (or lights as they say), no oil or water !! its good.
                    Ok MY CHOICE, no arguements there, but if you read some of my replies (you do need glasses right!!) you will see i "bang on" about variables and making things simpler, not for those in the western world who can pay people to design and build systems for them, but for the underground world of those who have to live OFFGRID.

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                    • #40
                      Gambia you are throwing out all kinds of numbers and variables with many questions tide to them. Honestly I do not have time to sort everything out and guess at what I am not certain about. That is what got us on the wrong track to start with, You are dealing with a technology, and all technologies require fairly precise measurements and calculations, then careful design applied and matching components to do the job.

                      So for now I will drop out of the conversation and leave it to the others to guess what you want and need. I am a pro, I don't like guessing. In my profession people can be killed or go broke if I am wrong.

                      Sorry and good luck.

                      SK
                      MSEE, PE

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                      • #41
                        @ Gambia river lodge

                        If you desire assistance, please post a listing of your gear :

                        example follows:

                        16 ea 46w PV panels, with the following specs:
                        32 VMP
                        39 VOC
                        1 A ISC
                        .8A IMP

                        4ea 225w PV panels, with the following specs:
                        72 VMP
                        89 VOC
                        3 A ISC
                        2.5A IMP

                        Brand XYC charge controller, model 1256 (and include a link to the MFG's data page)

                        Brand QRS Inverter, model 7260 (and include a link to the MFG's data page)


                        As Sunking said, getting all this data piecemeal, just makes it very hard for anyone to assist you.
                        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

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                        • #42
                          No worries SK, you have been great and very patient, i did not mean to come across as having a dig at you, it was supposed to be a bit of my humor (us English AHH!!). As for what i want and need, i am ok for now but will have many more facts and figures in two months. Looking back i made a mistake buy chucking everything i hope to do into the pot, that wont happen again.
                          Once again Thanks to you and everyone for all the help. Mike

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                          • #43
                            Mike it would help if you ask 1 question at a time with as much specific information as you can provide. If you do that I will help OK?

                            FWIW I understand and like British humor. Huge fan of Monty Python, an dI also know the terms are different like; Can I have a drag off your fag?

                            That has a completely different meaning on this side of the pond.
                            MSEE, PE

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