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  • #16
    I'm going to say, that your 2 panels in parallel, will not, at 28V, be enough to properly charge a battery. If they were 35Vvmp, that would be different. If you wired in series and used a MPPT controller, that would work, but you are not.

    But onto the sketch you posted:
    You only need a single 25A breaker, on the + lead to the PV panels. You show 2, 9A panels in parallel, which gives 18A, and your 15A breaker will pop
    The chances of the PV breaker actually tripping are slim, but it makes a very handy switch point, use a switch rated, DC breaker from Midnight:
    http://www.midnitesolar.com/productP...tOrder=6&act=p

    The battery, I like to recommend the Blue Seas dual MRBF fuse
    https://www.bluesea.com/products/215...k_-_30_to_300A
    BUT WAIT. You are series / paralleling 12V batteries to end up with 24V 400ah. That means you need 30-40A to properly charge the batteries, and you don't even have 20A from your PV

    The output of the controller to the battery, would go to a 50A fuse (or Breaker) to the battery

    The battery also needs protection with a series fuse on EACH battery (if you insist on paralleling)

    What are your loads ? Do you need 400ah ? What about using 4, 6V 200ah golf cart batteries in series, that gives you 24V @ 200ah and no parallel battery mess
    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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    • #17
      solar panel image.jpg Hi Mike, Just out of curiosity is it your birthday this week?
      Thanks for all the info and please excuse my ignorance. Just trying to get it right. Cannot go out and buy all this stuff as I already have the things I am talking about.
      Please have a look at the image of the rear of the panel I have purchased. I have 2 of them and in parallel I assume I am getting 24v and 500 watt.

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      • #18
        Hi Aussiemike,

        I assume that someone told you that these panels are 24 volt, but they're not. They are grid tie panels. 24 volt panels have 72 cells and have a VMP of about 36 volts and were originally made to charge a 24 volt battery with a PWM controller. As Mike said, a MPPT controller would be needed to charge your 400AH battery bank with the panel type you currently have. Four panels, 2 in series by 2 in parallel would allow a 7% charge rate, probably not adequate for daily cycling. Six panels, 2 in series by 3 in parallel would work well for charging this battery.
        3.6 kw PV, Classic 150, Radian GS4048A, LFP 195A

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        • #19
          Is this the Controller you are talking about?
          LCD 60A 80A 12V/24V MPPT Solar Panel Charge Controller Battery Regulator &USB
          This is the one I have.

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          • #20
            While this controller info isn't a link I copied and pasted it to eBay and every controller that came up is NOT an MPPT controller. These tricky Chinese manufacturers are so deceptive at labeling their products. I was just reading a thread where the OP had a Wellsee brand controller that, in their description of their controller, go into much detail to explain how MPPT controllers work. Problem is their controller is just a basic, (and pretty cheap), PWM controller. Here are a few examples of the fakes.

            Fake MPPT controller..jpgFake MPPT.jpg
            2.2kw Suntech mono, Classic 200, NEW Trace SW4024

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            • #21
              The one on the right looks familiar.

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              • #22
                You guys are scaring the hell out of me.
                How do I salvage this situation.
                Up till now everything was working.
                My only problem was I had 2 x 150AH batteries rigged in with 2 x 200 AH.
                Was running a freezer as a fridge using an INK BIRD.
                Bought 2 more 200AH to make things better. Seems I have messed up.
                What's my best way out?

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                • #23
                  No birthday anytime soon here.
                  The panels are "29V" panels. 24V batteries need at least 32V to be properly charged (like the 12V battery in a car, is charged at 15V, but never gets deeply discharged)
                  So, that's the first problem.
                  Second, I won't begin to guess what your charge controller is, but if you wired the 2 panels in series, for 58V, I would use either of these 2 controllers:

                  Morningstar solar PS-MPPT-25M (with meter & control panel $330 us https://www.morningstarcorp.com/products/prostar-mppt/
                  or
                  Midnight Kid $440 http://www.midnitesolar.com/productP...tOrder=1&act=p

                  Both are genuine MPPT controllers, work well, and are solid, both with some room for growth (the 25A morningstar is close to it's 25A limit, you could purchase the 45a version)

                  You still need breakers, and 20A of charging limits you to about 200ah of battery at 24V.

                  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


                  • #24
                    Can I do anything with the equipment I already have?
                    I already have 3 x 200 Watt 12v panels.
                    I have now bought these 2 x 24v 250 watt.
                    Is there any combination of these that might form a circle for me?

                    Comment


                    • #25
                      If your 200 ah. batteries are in good shape you can parallel the 3 200 watt panels into your PWM charge controller and charge them. while not ideal you can parallel wire two 12 volt batteries as long as you use opposite diagonal terminals for your connections. Don't just make your connections on the nearest battery.

                      Your 250 watt panels are most likely 60 cell panels, which need a MPPT controller to step down the voltage of. You can buy a small real MPPT controller, series wire the 2 250 watt panels and charge your 150 ah batteries wired for 24 volts or 12 volts.

                      You cant mix different batteries, period. You cant easily mix different solar panels unless they have very similar specs.

                      Here's the diagonal opposite battery connections. So you have a cable from positive to positive and a cable from negative to negative. This creates the parallel connections. All your load and charging connections will go to the opposite corners. Yes, all load and charging connections go to ONE positive terminal, likewise for negative connections.

                      the-correct-way-to-connect-two-batteries-in-parallel.jpg
                      Last edited by littleharbor; 02-08-2018, 07:46 AM.
                      2.2kw Suntech mono, Classic 200, NEW Trace SW4024

                      Comment


                      • #26
                        Originally posted by solarix View Post
                        two 250w panels in parallel is like 20amps max which could be done with as little as 12ga wire. 10ga is recommended - your 6ga is overkill..
                        I am new to solar panels. I am living in a camper and have roughly a 330Amp-Hour battery bank (setup for 12v), (3) 100watt solar panels, and a 20amp charge controller. I have all 3 panels connected to each other at the panels and then one run of 12AWG solar panel cable (included in my kit) back to the charge controller (about a 25ft run one-way). Based on the link that was posted for the wire sizing table, I should be using 4-6AWG cable, shouldn't I? That is if I want to keep my voltage drop to less than 3%.

                        If this is the case, a single 100watt panel shouldn't have a circuit length of more than about 30ft on a single 12AWG cable in order to keep the voltage drop less than 3%. Why are all the solar panel kits that have more than one panel supplying about 40ft of 12AWG or 10AWG cable with cable connectors to connect the panels to each other right at the panel? Are these kits not designed to have a voltage drop less than 3% and designed more around the 10% voltage drop range, or am I just missing something all together?

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                        • #27
                          Panels. Can I add an array of 2x12v 200A in series to an array of 2x24v 250A in parallel to the same controller?

                          Comment


                          • #28
                            First, get your terms correct . 200 amps?, no, watts.
                            Second 250 watt panels, without more details on these panels we don't know the voltages. 250 WATT panels sounds like 60 cell panels. If that's the case then the answer to your question is mostly no. You can mix any panels you want but results are going to be less than optimum. Voltages need to be within 10% to parallel panels without substantial losses.
                            Last edited by littleharbor; 03-04-2018, 07:11 AM.
                            2.2kw Suntech mono, Classic 200, NEW Trace SW4024

                            Comment


                            • #29
                              Apologies been a hard day.

                              I have array number one
                              2x12 volt panels of 200 watts each in series. Therefore 24v and 200 watts.

                              Then I have array number two.
                              2x24 volt panels of 250 watts each in parallel. Therefore 24v and 500 watts.

                              My question is can I connect both these arrays to a single (FAKE?) LCD 60A 80A 12V/24V MPPT Solar Panel Charge Controller Battery Regulator ???

                              Will I just loose serious performance or will I do damage?

                              Sorry for the previous post.
                              Cheers
                              MIke

                              Comment


                              • #30
                                That's right, you're on the other side of the world. I'm in California and just started my day.
                                You haven't answered if the 250 watt panels are 60 cell., which aren't considered 24 volt. they are considered 20 nominal in a battery charging scenario. A 24 volt (nominal) panel will have a Vmp. of about 35.5 to 37 and a Voc. of 44.5 to 47. 60 cell panels are usually around 30 Vmp. and 36 Voc.
                                Last edited by littleharbor; 03-04-2018, 07:40 AM.
                                2.2kw Suntech mono, Classic 200, NEW Trace SW4024

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