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  • Over Amperage to Charge Controller - MPPT-60

    Was wondering what happens if your PV Array puts out more amps than the charge controller is rated for.....like say your system puts out 80 Amps into a MPPT-60.

  • #2
    MPPT controllers, in general, can handle over sized arrays. They have the capability to throttle back the amps to stay within their heat and rated amp limit. I would not go much more than 150% over the controller rating. If your controller handles 4000w at 48V, it could most likely handle 6000w and still be able to self limit. A lot depends on the array voltage and how the controller "de-tunes" the PV array to stay within limits.
    In all cases, follow the mfgs suggestions.
    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


    • #3
      You will clip some of the amps but more than likely if the CC is not built to handle 80 amps in then you could burn it up.

      Comment


      • #4
        Originally posted by Zardiw View Post
        Was wondering what happens if your PV Array puts out more amps than the charge controller is rated for.....like say your system puts out 80 Amps into a MPPT-60.
        Not really possible unless you really have no clue what you are doing. MPPT Controllers are Buck Converters meaning they convert a higher voltage (lower Current) to lower voltage higher current. In other words an oxymoron or DIY question. Just not something you would ever do. Possible, but you would have to work really hard to be a foolish moron.

        You would really have to way over size the panels considerably to even have the Input Current = Output Current whihc would mean you just changed your MPPT Controller into a PWM Controller, thus throwing or clipping 30 to 35% of your power into the garbage can. Not too mention woul dmean the panels are configured wrong



        MSEE, PE

        Comment


        • #5
          Originally posted by Mike90250 View Post
          MPPT controllers, in general, can handle over sized arrays. They have the capability to throttle back the amps to stay within their heat and rated amp limit. I would not go much more than 150% over the controller rating. If your controller handles 4000w at 48V, it could most likely handle 6000w and still be able to self limit. A lot depends on the array voltage and how the controller "de-tunes" the PV array to stay within limits.
          In all cases, follow the mfgs suggestions.
          Thank you!........It's a Morningstar MPPT-60 .......Good to know I can hook up enough panels to where at times under high sun, it will put out more than the 60 Amps it's rated for.....

          Most of the time it probably won't go over that......but when it does, I imagine I'd be wasting power from the panels........power that is over the 60 Amp rating.

          Fwiw, I've got a DIY 24 volt system, and right now I've got 7 panels hooked up......that have 67 cells each.....

          I'll take current measurements in the summer time when they're putting out max......and if I'm generating way too much, I'll switch some panels to another controller.....

          Thanks again!
          z

          Comment


          • #6
            Originally posted by Zardiw View Post

            Thank you!........It's a Morningstar MPPT-60 .......Good to know I can hook up enough panels to where at times under high sun, it will put out more than the 60 Amps it's rated for.....
            No, it will always limit to 60 amps max. I would be careful about oversizing the array to too high of voltage, no more than 3x your battery voltage. Morningstar may have some info on their web site where they cover the danger limits.



            Most of the time it probably won't go over that......but when it does, I imagine I'd be wasting power from the panels........power that is over the 60 Amp rating.

            Fwiw, I've got a DIY 24 volt system, and right now I've got 7 panels hooked up......that have 67 cells each.....

            I'll take current measurements in the summer time when they're putting out max......and if I'm generating way too much, I'll switch some panels to another controller.....

            Thanks again!
            z
            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


            • #7
              Hello forum. I have been thinking of doing something like this with the roof-top panels on my Ford Transit Van.

              I currently have two(2) x 150W panels spanning the front half of the roof, feeding into a 360W 30A 12V MPPT controller which was only finally connected and set running last Thursday morning, February 28th. Plan A is to save the money to purchase another pair of the same 150W panels to fit to the rear of the van and connect these to a second 360W MPPT controller. I was told by the fellow at the shop that hooking 600W total power into the single 360W MPPT controller will fritz the controller, but it makes me wonder.

              You see, last Friday when I took the first and only drive out of the shady spot under the trees by the river where my Transit Van and I are parked now, and stopped at the electronics shop where I have been buying all these solar goodies, I took a reading of the incoming current to the MPPT and even at 11am on a clear, sunny day at 33*S on March 1st, the two 150W panels were only managing 14A or less combined, and 300W / 12V = 25A. I figured that the 150W rating applies to high noon in Singapore at the equinox on a cloudless day, (which is unlikely to occur in Singapore at the equinox anyway).

              Suppose I head north to Darwin, which is 12.5*S latitude, and my panels are almost perpendicular to the Sun. I doubt that even thenm these two 150W panels will exceed 20A mainly due to the light gauge cabling and my sloppy connector terminations. So say I was to scrimp in that second MPPT controller and connect the second pair of 150W panels to the single 360W controller, totalling 600W input theoretically, but more likely feeding not more than 40A into a 30A MPPT controller.

              That is what I hope to achieve, not just to save some money and hurry this project on by a couple of weeks, but mainly so that I can achieve more consistency when the Winter comes and the sky is cloudy. Having four panels up top to do the work of two seems like a kind gesture to my solar assemblage. The concern is that on a sunny day, would a current input of 40A wreck a 30A MPPT controller, or would it have the brains to moderate the input and continue to output 30A.

              It is a Powertech MPPT controller sold by JayCar in Australia. 360W, 30A, 12V and looks like a fairly good quality Chinese product. Should I attempt to wire in a third panel with the current two, and take the van for a drive in the sun and see how the current is flowing? Then, if three panels in the sun are making less than 30A, I could perhaps hool in the fourth panel for the drive home and see if it works.

              Can anyone enlighten me with some personal experience on the foolishness of this Plan B?

              Comment


              • #8
                NO. Your batteries are partially charged, and they are not drawing full current. Want to test this ?

                Get a opaque dark tarp, use your batteries all night, cover the panels with the tarp (or switch them off, leaving the controller still powered by the battery) Wait till noon and power the panels up and feed the charge controller, you will see full power for a couple minutes.
                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


                • #9
                  Originally posted by Seano View Post
                  Hello forum. I have been thinking of doing something like this with the roof-top panels on my Ford Transit Van.

                  I currently have two(2) x 150W panels spanning the front half of the roof, feeding into a 360W 30A 12V MPPT controller which was only finally connected and set running last Thursday morning, February 28th. Plan A is to save the money to purchase another pair of the same 150W panels to fit to the rear of the van and connect these to a second 360W MPPT controller. I was told by the fellow at the shop that hooking 600W total power into the single 360W MPPT controller will fritz the controller, but it makes me wonder.

                  You see, last Friday when I took the first and only drive out of the shady spot under the trees by the river where my Transit Van and I are parked now, and stopped at the electronics shop where I have been buying all these solar goodies, I took a reading of the incoming current to the MPPT and even at 11am on a clear, sunny day at 33*S on March 1st, the two 150W panels were only managing 14A or less combined, and 300W / 12V = 25A. I figured that the 150W rating applies to high noon in Singapore at the equinox on a cloudless day, (which is unlikely to occur in Singapore at the equinox anyway).

                  Suppose I head north to Darwin, which is 12.5*S latitude, and my panels are almost perpendicular to the Sun. I doubt that even thenm these two 150W panels will exceed 20A mainly due to the light gauge cabling and my sloppy connector terminations. So say I was to scrimp in that second MPPT controller and connect the second pair of 150W panels to the single 360W controller, totalling 600W input theoretically, but more likely feeding not more than 40A into a 30A MPPT controller.

                  That is what I hope to achieve, not just to save some money and hurry this project on by a couple of weeks, but mainly so that I can achieve more consistency when the Winter comes and the sky is cloudy. Having four panels up top to do the work of two seems like a kind gesture to my solar assemblage. The concern is that on a sunny day, would a current input of 40A wreck a 30A MPPT controller, or would it have the brains to moderate the input and continue to output 30A.

                  It is a Powertech MPPT controller sold by JayCar in Australia. 360W, 30A, 12V and looks like a fairly good quality Chinese product. Should I attempt to wire in a third panel with the current two, and take the van for a drive in the sun and see how the current is flowing? Then, if three panels in the sun are making less than 30A, I could perhaps hool in the fourth panel for the drive home and see if it works.

                  Can anyone enlighten me with some personal experience on the foolishness of this Plan B?
                  A true MPPT charge controller is able to limit the amount of power it takes from the array to control the output current to the batteries. But some manufacturers still specify not to exceed some multiple of the input power required to produce the rated output. That multiple may be as low as 1.5, or go to 2 or more. Other manufacturers simply do not put a limit on allowed array power, but the extra power capability will simply be wasted.

                  A PWM CC, on the other hand, tries to regulate the average output current by switching the panel circuit on and off at a high frequency. During the time the switch is on the current may be limited only by array power and may exceed the maximum instantaneous current of the control elements if the array is too large.

                  There are a large number of suspiciously low priced Chinese-made CCs which are marketed as MPPT but are really PWM that has been modified for poorer performance to give the illusion that it is MPPT. One of those will surely fry with too large an array.

                  In your case the situation is complicated by your panel arrangement. Other than at the equator at noon, a horizontal panel will produce far less than the rated output, even under full clear skies.
                  And the rated power usually assumes that the panel temperature does not exceed 25C, unlikely on top of a vehicle in full sun. So you really need to look at what the array is actually producing, not its nominal power, in figuring out what you can use to drive your CC.
                  SunnyBoy 3000 US, 18 BP Solar 175B panels.

                  Comment


                  • #10
                    Originally posted by inetdog View Post
                    There are a large number of suspiciously low priced Chinese-made CCs which are marketed as MPPT but are really PWM that has been modified for poorer performance to give the illusion that it is MPPT. One of those will surely fry with too large an array.
                    Thank you for your reply to my inaugural post, InetDog. Your expertise is appreciated, because while I don't think that the reputable Australia-wide JayCar company would take such cheap shots at customers, there is that kind of shonky business that you mention above. I would assume that by the look, feel, smell & taste of this new controller, as well as the quality of the box & packaging, and the 99% good grammar of the English in the User Manual, and also the reputation of the retailer, (who sell PWM controllers as well, for around 20% of what this MPPT just cost me), that it most likely is what it claims to be.

                    However, I think I might take it carefully with this next stage of the project anyway, considering your warning on MPPT quality from Shenzhen and such places. I will conclude below.

                    Originally posted by inetdog View Post
                    And the rated power usually assumes that the panel temperature does not exceed 25C, unlikely on top of a vehicle in full sun. So you really need to look at what the array is actually producing, not its nominal power, in figuring out what you can use to drive your CC.
                    Interesting, because there is a temperature sensor which I have plugged into its port under the controller but am yet to hook into a spot near the batteries, and the User Manual tells me that the MPPT controller can adjust the output current to suit the temperature of the battery. How this relates to the temperature of the panels on the roof is another question, but as you mentioned, the little dual (inside/outside) thermometer I have in front of the desk here in the back of the van (behind the seats) told me that it was 43*C up on the roof-rack at one stage yesterday afternoon, when it was only 37*C in here.

                    I have some time to consider carefully, but based on your advice, I am inclined to take the Plan C which just eventuated when I was writing the last post. I will purchase the two additiional panels first, with the MC4 connectors already wired into the middle of the roof-rack and then through into the van to a fuse-block, but there are no blade-fuses plugged in yet.

                    I'll test one extra panel under a tree in the shade first, by plugging its 20A fuse in, then keep a hand on top of the MPPT controller box to sense heat, and keep the nose on guard for brown smells, and watch the LCD screen for E3 error, which indicated 'Module current too high' and give it half an hour. If that doesn't burn my house down, I'll disconnect the fuse, drive out to a place in the sun, and repeat the procedure with the third 150W panel, using the fuse to start the test again.

                    I reckon that such a methodology would probably allow me to monitor any unhealthy symptons in the MPPT controller, would you agree?

                    There seems like quite a good education to be gained here at this forum, so I will keep monitoring this thread and also read some more of the information. Thank you once again, sir.

                    Comment


                    • #11
                      You are very welcome. Keep coming back!
                      SunnyBoy 3000 US, 18 BP Solar 175B panels.

                      Comment


                      • #12
                        After looking up your controller I think you may have a bogus MPPT controller. I don't give Youtube videos much value but I did look at the side by side test video for this controller and a known true MPPT controller and it seems to verify my suspicions.
                        2.2kw Suntech mono, Classic 200, NEW Trace SW4024

                        Comment


                        • #13
                          Originally posted by littleharbor View Post
                          After looking up your controller I think you may have a bogus MPPT controller. I don't give Youtube videos much value but I did look at the side by side test video for this controller and a known true MPPT controller and it seems to verify my suspicions.
                          Could you post the link to the video please? I am still uncertain whether you're referring to my controller ot the MPPT-60 that the OP inquires about.

                          Comment


                          • #14
                            Originally posted by Seano View Post

                            Could you post the link to the video please? I am still uncertain whether you're referring to my controller ot the MPPT-60 that the OP inquires about.
                            https://www.youtube.com/watch?v=-VP1LCp_qfI
                            2.2kw Suntech mono, Classic 200, NEW Trace SW4024

                            Comment


                            • #15
                              Originally posted by littleharbor View Post
                              Thanks Littleharbor. It was mine you referred to as I suspected.

                              I'm sad to see that the company I've trusted for the past ten months with the vital electrics of my life here have been labelled as crooks like that by Adam. How much cred' to give to that youtube video and its sequel is an important question. Whether Adam is motivated by a good reason to share honest information with the public or whether he is motivated by spite against JayCar is another related question. One would have to know Adam a lot better to know Adam's motives a little better.

                              I don't understand why he has adjusted his float voltage up from 13.7 default to 14.1 and can only assume that he's lucky to have the money for LiFePO4 batteries, while us peasants are floundering around with our plain old SLAs and we don't mind 13.7 float voltage. That might explain why the MP-3735 is stuck on Float at the time of the video. If the settings on the Victron controller were explained, and if there was some illustration of the panel arrrangement and lighting at the time of the voltage reading ... it's a hard one to judge either way, but I'm very sad and unhappy now anyway. I am so sad I am sitting here with my diesel running on a cloudy day, puffing dirty black smoke up into the sky and hoping that the wind will blow it all over JayCar which is SSW of here around 20km, and I don't really give a damn if everyone between here and there gets smogged out by my diesel as collateral damage.

                              I just spent all my money on dud solar equipment and so what reason could there possibly be for me not to adopt the F.T.W attitude?.

                              PS: Okay, Deep Breath. Hissy-fit Complete.

                              Seriously, I'm getting 14A out of twin 150W panels in clear, sunny skies at 33*S latitude before 11am a couple of weeks before the equinox and that's enough to keep me running with amps to spare.

                              Currently, right at this very moment in time, I've got the portable 120W (60W x 2) foldup panel out front on a dull, cloudy day in the rain with no shadow definition to be seen beneath the trees and my little (overpriced underpowered) MPPT MP-3735 is still dragging in 1.9A which is about half enough to keep the food cooler and the laptop alive (without movies of course). When I get the other two panels installed at the back of the van, I'll have 300W fixed roof-top solar plus the 120W portable, and the controller I've got does seem to be able to operate in various conditions, rain or shine.

                              It could be worse, could be worse indeed, and Adam can't work out how to calculate his own watts when he is given the amps and volts, I'll stop being so sad and make the best of whatever I've got.
                              Last edited by Seano; 03-06-2019, 08:17 PM.

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