Announcement

Collapse
No announcement yet.

Will this charge controller work?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Will this charge controller work?

    Hi, I'm researching a solar set up and I'm trying to figure out which charge controller to use.
    I plan on using 7 100w panels in series making 84v 8.3a with a mppt charge controller.

    I will be using 2 of these http://www.amazon.com/dp/B00ACNO2AO/...I1TQVZK7V9ZBWH
    which are 12v 125ah batteries which I will be connecting in series.

    The battery manufacturer states a charging current of 8A-35A and a charging voltage of 14.4V-14.9V for the batteries.
    It also says under "charging options": Solar Panel: 175W-450W (120W may be used if Depth of Discharge would not exceed 50%)

    The charge controller I'm looking into is http://www.amazon.com/dp/B00WZFPLE8/...I1QNNN93KACZGL.
    Which states a "rated battery current" of 40a and a "charging limits voltage" of 15.5v

    So my questions are
    1. The batteries state a max current of 35 amps. The solar panel amp output is 8.3. Does "rated battery current" mean the charge controller will output 40 amps into the battery or is that a max rating?
    2. The max charging voltage of the battery is 14.9v. The charge controller states a "charging limits voltage of 15.5v;x2/24" Does that mean the charge controller is too powerful for these batteries?
    3. The battery manufacturer states under "charging options" 175w-450w solar panels. Does that mean a 700w panel system is too powerful for these batteries eve with 2 in series?

    Here are the full specs of the charge controller
    http://ecx.images-amazon.com/images/I/61YLsPaxB%2BL.jpg
    http://ecx.images-amazon.com/images/I/51G12ONNrLL.jpg

  • #2
    To answer you question yes 700 watts in panel would be too much for the battery
    if its max charge current is 35 amps. Charge Controller Output Amps = Panel Wattage / Battery Voltage
    So 700/12=58amps. with a MPPT charge controller.

    I am betting the panel are probably 18-22v voc this will be the voltage
    you have to use when hooking panels in series to an MPPT charge controller.
    You cannot exceed the max input voltage of the charge controller based on the voc.
    So if the max input is 100volts and your panels are 20voc then you can only use 5 in series.

    The 700 watts being to much for the battery still stands regardless.
    400 watts is all you need as that will give you 33amps

    Here is a thread to help you with your designing

    http://www.solarpaneltalk.com/showth...Battery-Design

    Comment


    • #3
      Originally posted by coinmaster View Post
      Hi, I'm researching a solar set up and I'm trying to figure out which charge controller to use.
      I plan on using 7 100w panels in series making 84v 8.3a with a mppt charge controller.
      There are a couple of immediate flaws in your planning:
      1. The panels are clearly "battery" panels designed to be used with at most a PWM CC to charge 12V batteries. The nominal voltage is given as 12V for that reason.
      As pointed out the actual Vmp of each panel is likely to be around 18V and the open circuit voltage will be more like 22 volts. That means you cannot use 7 in series with that CC.
      2. The price per watt of battery panels is typically between two and three times the price per watt of higher voltage panels designed for use with a grid tie inverter or an MPPT CC. Do not plan your system around these panels unless you have a way of getting them free. You can get higher voltage panels for less than $1 per watt if you shop around.

      Also, you mention using two batteries in series, giving you 24V at 125AH. I think that Legacy missed that point in his analysis of your CC operation. But 700W is still about twice the panel power that would be optimal for 24V/125AH. The charging current should be around 10A for that string. 700 watts at 24V with an MPPT CC would be less than 30A.
      SunnyBoy 3000 US, 18 BP Solar 175B panels.

      Comment


      • #4
        Yes I did miss his 24 volts for the batteries , not quite awake when I wrote the reply , thx inetdog
        but he should be able to figure it out if he follows the thread I posted from Sunking
        and the 12 volts I used is an example.

        Comment


        • #5
          Originally posted by coinmaster View Post
          Hi, I'm researching a solar set up and I'm trying to figure out which charge controller to use.
          I plan on using 7 100w panels in series making 84v 8.3a with a mppt charge controller.
          How are you coming up with that? 100 watt battery panels are roughly 21 Voc, Vmp = 18, Imp 5.3 amps. 7 in series Voc = 147 volts what far exceeds any controller input. Additionally what you will discover you cannot use a PRIME number of panels. With 7 panels you only have two options.

          1. All in series which will not work with a controller.
          2. All in parallel which will not work on 24 volt battery.

          Not much point in me saying anything else because what you have just does not work unless you loose a panel to configure 3 x 2.
          MSEE, PE

          Comment


          • #6
            I seem to be a bit out of my league here I think.
            The panels I will be using are http://www.grapesolar.com/specs-100w...star-100w.html

            I noticed you said they are overpriced.

            So I looked around for grid tied panels and found something like this http://webosolar.com/store/en/grid-t...cs6x-310p.html

            What's the catch?

            Sorry I'm about 2 days old to the concept of solar so I'm still learning.

            Comment


            • #7
              Originally posted by coinmaster View Post
              I seem to be a bit out of my league here I think.
              The panels I will be using are http://www.grapesolar.com/specs-100w...star-100w.html

              I noticed you said they are overpriced.

              So I looked around for grid tied panels and found something like this http://webosolar.com/store/en/grid-t...cs6x-310p.html

              What's the catch?

              Sorry I'm about 2 days old to the concept of solar so I'm still learning.
              The Canadian Solar panels are going for a little less than $1/watt. That is reasonable. No catch. It is less expensive per watt to make a panel with a larger number of cells in series (higher voltage/Grid Tie) than smaller panels. And they are produced in larger quantity since there are far more GTI installations than battery installations. End result is lower cost per watt. Also easier to wire, as long as you are going into a true MPPT CC.
              The Grape Solar link did not specify prices. What have you been quoted on those?
              SunnyBoy 3000 US, 18 BP Solar 175B panels.

              Comment


              • #8
                Grape solar is about 1.5$/w
                after looking around more I found http://www.eco-distributing.com/prod...lsKhoC9A_w_wcB
                which I can buy 3 of for 750w which can be used with http://www.amazon.com/dp/B007PHTQMY/...I2YM5ZC6P4Y3NI charge controller.

                I checked out the specs to the detail and it seems that charge controller would work perfectly with the panels and the batteries. I know that 750w is overkill for 125ah 24v batteries but I'd rather have more power than more storage since I live in a cloudy area.
                The main reason I'm stuck on 700+ watts is that while using a solar calculator the jump from 600w to 700w in charge times is 1.3 days to 2 hours in december sun, therefore I should be able to remain at full charge.
                The only problem I have is that the tutorials for the midnite charge controllers are filled with complex connections in pv combiner boxes and epanels.

                I don't completely understand the purpose of combiner boxes and epanels but I will be using my solar set up with http://www.amazon.com/dp/B00AYH6CBU/...I3KTDCKE62OODI totally off grid by a lake which I will feed into a tent camp. Not any kind of on-grid or house set-up.
                Is there a need for all those panels and boxes and whatever?

                Comment


                • #9
                  Originally posted by coinmaster View Post
                  I don't completely understand the purpose of combiner boxes and epanels but I will be using my solar set up with http://www.amazon.com/dp/B00AYH6CBU/...I3KTDCKE62OODI totally off grid by a lake which I will feed into a tent camp. Not any kind of on-grid or house set-up.
                  Is there a need for all those panels and boxes and whatever?
                  When you have two or more parallel strings of panels requires combiners and fuses. With just a single string of 3 panels, no combiner or fuses are required or needed.
                  MSEE, PE

                  Comment


                  • #10
                    Originally posted by coinmaster View Post
                    Hi, I'm researching a solar set up and I'm trying to figure out which charge controller to use.
                    I plan on using 7 100w panels in series making 84v 8.3a with a mppt charge controller.


                    The charge controller I'm looking into is http://www.amazon.com/dp/B00WZFPLE8/...I1QNNN93KACZGL.
                    Which states a "rated battery current" of 40a and a "charging limits voltage" of 15.5v


                    Here are the full specs of the charge controller
                    http://ecx.images-amazon.com/images/I/61YLsPaxB%2BL.jpg
                    http://ecx.images-amazon.com/images/I/51G12ONNrLL.jpg
                    I Hope you didn't buy the controller in your post yet, because it is the same controller like this one which sell for half price.

                    http://www.amazon.com/s/ref=nb_sb_no...rge+controller

                    Comment


                    • #11
                      Yeah I figured that out
                      It seems in the end I'm going to go with http://www.ecodirect.com/ProductDeta...SRsxoCDbHw_wcB

                      It's weatherproof and will handle up to 162v.

                      Comment


                      • #12
                        That is a 30 amps controller, you definitely need to go 24 volt battery bank to take all your panels. Also the 168 volt maximum input volt is hyper volt with 48 volt battery bank. it only work blow 120 volt, it can take 168 volt with 48 volt battery bank won't damage the controller but it won't put out any power until the voc drop back below 120 volts.

                        Comment


                        • #13
                          The midnite charge controller calculator gave my set up the "ok".

                          My panels should have a combined 112v output. The calculator says it would hit 120 at -24 degrees.

                          Comment


                          • #14
                            to save another $60, if you don't need the marine version:
                            http://www.ecodirect.com/Midnite-Sol...-solar-kid.htm

                            I know the full size classic can be programmed to limit the battery amps, so you could overpanel and let the controller limit the amps, and still have extra panel for the less optimal months.
                            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


                            • #15
                              I'll be living in this http://www.cabelas.com/product/Cabel...tabsCollection on a lake so I definitely need the marine version. The entire solar set-up will be outside other than the inverter.

                              750 watts at 24 volts is 31 amps so it's just barely within the amp range of my battery.

                              Comment

                              Working...
                              X