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Aloha in advance. Solar newbie needs help with system.

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  • Aloha in advance. Solar newbie needs help with system.

    Aloha guys and girls
    I'm a newbie to solar, yet a quick learner. I Could use some help with figuring out my some issues with my off grid setup. Please feel to chime in.

    12v Setup as follow:

    Solar panels: 5 Hyundai @270 watts: 31.4v:8.6A. (1350)

    Charge controller: Tristar ts-60 pwm

    Battery's: 12v 8 140ah eaton battery's

    Wires: BIG (not sure on gage)

    Multimeter: eBay 13$

    Load/usage:

    I run (8) 13 watt led lights for 10 hours a night and I'm looking to add another 8(fingers crossed) 8x13=104wh=104x10hrs=1040wh a night I use according to a formula I got off a website while researching about off grid set up. (Correct me if I'm wrong on the formula)


    Issues:
    While load is on, my multimeter reads 40w being drawn, and at the end of the 10 hours only 400 wh was used not the 1040 the formula suggest. Either my formula is wrong or my meter is worth the entire 13 dollars I spent on it. Chime in please?



    Issue 2:

    On a good day my system hits 100-200ah and on what I call a bad day it averages from 50-100ah. The amps generated from my array average 10-40 throughout the day. My battery's hits Pmw mode but never equalize or float. My question is ideally speaking how long will I have to charge them to enter these charging states? Is my usage to much for my system?


    Issues 3
    Battery's got to its lowest this morning 12.33 (scares the hell out of me) with the load on, after load was shut off the multimeter read 12.42 as the sun came out it got to 13.15 at its peak(no where near 15.0 Pmw)

    12.42-12.90 at the end of the day which hit 210ah from my array, does that sound good? Again I'm reading this all off of my multi meter.

    Any help would be good. I'm just trying to learn and run a efficient solar system.

    Aloha
    Hidope808










  • #2
    I will post pics when I get better connection.

    Comment


    • #3
      Hello HiDope808 and welcome to Solar Panel Talk

      While it would be nice to get some more information on your system I can see a few issues.

      First is that with a PWM CC, you are turning that 1350 watts into less than 600 watts and only getting maybe 42 amps of charging.

      Next with a 12v battery system with 8 x 140Ah units (I presume they are all wired parallel) you have a 1120Ah "battery" that needs over 100Amps of charging. With only 40+ you are not even half way there.

      Finally having more than 2 batteries wired in parallel is a big issue since they will never charge or discharge equally no matter what size wire you have used. There are just too many different paths with different resistance levels to make charging balanced.

      Comment


      • #4
        Here is some pics
        Attached Files

        Comment


        • #5
          Aloha suneagle

          Here I am thinking my charge controller is working full power. Which CC would you suggest for me, I need my lights every night, so getting my system to operate at full power is the only option.


          The Amp hours it's saying that it charged is not where near accurate from what your saying? Im confused.


          What if I was to turn four 12v Amg batt into 2-24v batts would that help with charging my batts to full power?

          Comment


          • #6
            You say your wires are "big (not sure on size)". While you are not clear which wires you are referring to. I would say the wires, (cables?) on your batteries appear to be quite undersized for most applications.
            2.2kw Suntech mono, Classic 200, NEW Trace SW4024

            Comment


            • #7
              Originally posted by HiDope808 View Post
              Aloha suneagle

              Here I am thinking my charge controller is working full power. Which CC would you suggest for me, I need my lights every night, so getting my system to operate at full power is the only option.


              The Amp hours it's saying that it charged is not where near accurate from what your saying? Im confused.


              What if I was to turn four 12v Amg batt into 2-24v batts would that help with charging my batts to full power?
              That PWM type charger will still convert only 67% of your panel wattage to charging amps.

              The best way to get the most out of your panel wattage would be to use an MPPT type CC. But your limitation for a 12volt battery system is about 1000 watts and an 80amp CC.

              If you go to a 24v battery system then you can use more panel wattage but still need a 60amp MPPT for your 1350 watts.

              I also agree with littleharbor. The wires connecting your batteries in that picture seem pretty small to me and won't handle 60 amps of charging. They need to be a minimum of #6 AWG or larger.

              Comment


              • #8
                Originally posted by SunEagle View Post

                That PWM type charger will still convert only 67% of your panel wattage to charging amps.

                The best way to get the most out of your panel wattage would be to use an MPPT type CC. But your limitation for a 12volt battery system is about 1000 watts and an 80amp CC.

                If you go to a 24v battery system then you can use more panel wattage but still need a 60amp MPPT for your 1350 watts.

                I also agree with littleharbor. The wires connecting your batteries in that picture seem pretty small to me and won't handle 60 amps of charging. They need to be a minimum of #6 AWG or larger.
                I think OP is using only about 40% of his panels energy. I mean PWM CC would make panel work at 12V battery voltage so even directly connected it can produce only 12V x 9A = 108W which is 40% of his panel rated power. Tristar ts-60 charge controller allows charging 24V batteries so he could simply connect 2x 12V batteries in series and this would double energy going from panels into the batteries. MPPT controller would be even better of course.

                OP- what is that multimeter showing? Was it the moment when the system was charging during a day or was it current consumed by LEDs at night?

                Comment


                • #9
                  Originally posted by max2k View Post

                  I think OP is using only about 40% of his panels energy. I mean PWM CC would make panel work at 12V battery voltage so even directly connected it can produce only 12V x 9A = 108W which is 40% of his panel rated power. Tristar ts-60 charge controller allows charging 24V batteries so he could simply connect 2x 12V batteries in series and this would double energy going from panels into the batteries. MPPT controller would be even better of course.

                  OP- what is that multimeter showing? Was it the moment when the system was charging during a day or was it current consumed by LEDs at night?
                  I agree that as you increase the panel wattage you end up using a smaller percentage if you have a PWM CC. The best a PWM can do is get you about 67% once you exceed 200 watts. Anything above that figure will be like beer foam and a waste of money.

                  Comment


                  • #10
                    Originally posted by max2k View Post

                    I think OP is using only about 40% of his panels energy. I mean PWM CC would make panel work at 12V battery voltage so even directly connected it can produce only 12V x 9A = 108W which is 40% of his panel rated power. Tristar ts-60 charge controller allows charging 24V batteries so he could simply connect 2x 12V batteries in series and this would double energy going from panels into the batteries. MPPT controller would be even better of course.

                    OP- what is that multimeter showing? Was it the moment when the system was charging during a day or was it current consumed by LEDs at night?



                    That was current being drawn from the led at that moment in time. According to the formula watts x hours of usage= I should being drawing 104 watts x10= 1040 watts a night , instead my meter reads after a 10 hour night that I consume roughly 450 wh a night. I'm not sure.


                    today I tried hooking it up as a 24 v system. And realized that my inverter could not be used. Buying a 24 v inverter before tonight was not an option. Wired my batt bank with bigger wires.

                    Comment


                    • #11
                      Originally posted by HiDope808 View Post




                      That was current being drawn from the led at that moment in time. According to the formula watts x hours of usage= I should being drawing 104 watts x10= 1040 watts a night , instead my meter reads after a 10 hour night that I consume roughly 450 wh a night. I'm not sure.


                      today I tried hooking it up as a 24 v system. And realized that my inverter could not be used. Buying a 24 v inverter before tonight was not an option. Wired my batt bank with bigger wires.
                      and what is your inverter model # and how it is hooked to your LEDs? This is the first time you mentioned it, I thought you were feeding your LEDs DC directly from batteries. AC is of course more versatile and would let you use standard loads/standard wiring/switches/etc but it requires extra installation efforts.

                      Since inverter is involved I think the problem with your multimeter could be related to the current waveform shape- while voltage is more or less constant the current can have significant AC component throwing off your multimeter readings. Since it multiplies them to get power and then energy all those values will be off as well. It would help if you can get good (better than 1% accuracy) true RMS DMM and compare its reading of the current with your multimiter. Hooking up scope to the current shunt would also allow confirming this idea but it sounds you don't have access to such equipment.


                      In any case with 12V setup your panels are severely under- utilized (40% max) due to voltage mismatch: panels would produce their max rated power around their Vmp = 31.4V but your PWM controller would drag them down to battery charge voltage, something around 13V tops. If you either find MPPT controller or at least manage to hook up batteries to 24V your 5x 270W panels can be better used.

                      270W x 13V / 31.4V = 111W each to the total of 550W / 2.5kWh / day. While it seems enough from energy point of view the charging current to your batteries will be 550W / 13V = 42A as SunEagle said above.

                      switching to 24V would change this to:
                      270W x 26V / 31.4 = 223 W, total 1115 W / 5.5 kWh / day, Charging current to 24V batteries would remain the same: 1115W / 26V = 42.8A but since you'd be charging 2 batteries in series you will be extracting twice the energy from the same panels as you do now.

                      using MPPT charge controller would make this calculations match to what you had in mind at the beginning:
                      270W would produce 270W without any reduction, 5 panels would have 1350W max power to the total of 6750 kW/day producing 1350W / 13V = 103A charging current at 12V (if controller / batteries / wiring could handle that) or more sanely: 1350W / 26V = 52A for 24V system.

                      Please note all the numbers above are for the same 5 panels you have, it makes big difference what equipment you have and how you use it.

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