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not all pwms controller are pwm not all pwm are 3 stages and not all mppt are mppt

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  • not all pwms controller are pwm not all pwm are 3 stages and not all mppt are mppt

    hi

    we live in the era of exaggeration...i tried last days to study how pwm controllers (commercial units) are build and what logarithm they use to charge the batteiries

    not to mention that many of these units are not even a pwm ...some are just on off controllers ..a mosfet switch on allow panel to be perfectly parallel to battery

    and that is it the panel will act as current source to charge the battery ..when battery is full the controller open the fet


    some are really pwm but they are not 3 stages ...3stage pwm charge is perfect to maintain batteries integrity 3 stage charging first start by "bulk stage "

    allowing panel to be in parralel with the batteries till predefined voltage level ...after that it switch to pwm ...while watching the current draw from panel to batteries

    when it is a predetremind low level the switcher change to float mode ...in this mode the voltage level will be lowered to known

    some level and stay there (pulsing from time to time)


    some pwm out there despite the fact they they are really pwm but they do not apply this charging method


    all they do is to pwm it at 100 duty cylce "that is for bulk" and then pwm at much lesser duty cycle till the battery reach certain level and then it just quits


    that literally not 3 stages charging plan....the change from bulk to pwm ..is ok but pwm should stay till current draw from battery drop down

    and then it should go to float mode not quits??



    not to mention mppt controllers who are sold as mppt yet it dont have the current gain not it have that bulky coil inside the unit

    here is schamtic for the pwm diy type (normal pwm not 3 stages..bacause i cant see current measuremnt...and the man who make this diy confess it so no blame on him since



    he is giving it for free but those who recieve the $ are to be blamed ) ...i really wanted to master the art of recognising and tearing controllers down and scoping them to discover


    whether they are really pwm or not and if they pwm do they have the 3 stages charging mode or not and how they manage to to measure current to switch from pwm mode to


    float mode ??links shcmetics of real pwm commercial controllers and real 3 stages ..pdfs manuals all is welcomed thanks for all
    Attached Files

  • #2
    Current is easily measured as voltage drop across the FET. Other things have been "left out" of your schematic, such as the PWM generating circuit, only the final transistor is shown, not all the sensing and control circuit.
    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
      PWM is nothing more than a MOSFET Switch. 3 stage charging is really a meaningless marketing term meaning 3 voltage set points. Lastly 3-stage charging is not compatible with Solar because there are not enough Sun Hours in a day to complete 3 stages. So i am not really sure what you are driving at.

      Al PWM controllers work the same by modulating the Pulse Width Duty Cycle. At 100% modulation the MOSFET is turned on connecting the panel directly to the battery forcing the controller to act as Constant Current Source. When the battery voltage reaches a Set Point, then the controller switches and behaves as a Constant Voltage source for the last two stages modulating the Pulse Width by turning the MOSFET On/Off duty cycle less than 100%.

      Inn most applications you are better off not using any controller if you want to use PWM controllers. All you need is a diode to prevent the panel from back feeding the panel after sunset. That keeps the panel in CC mode to deliver all the power it can. Only time a Solar really stands a chance of fully charging batteries is in Summer. Problem is 90% of folks do not have enough panel wattage to ever fully charge a battery. In that case one should use a MPPT Controller with all 3 stages set to 16 volts for each 12 volts of battery. That forces the controller to stay in BULK mode or Max Smoke all day to get the battery charged up as much as possible. Then once a week use generators to saturate the battery on a 12 hour run.
      Last edited by Sunking; 01-24-2017, 08:36 PM.
      MSEE, PE

      Comment


      • #4
        Originally posted by Sunking View Post
        PWM is nothing more than a MOSFET Switch. 3 stage charging is really a meaningless marketing term meaning 3 voltage set points. Lastly 3-stage charging is not compatible with Solar because there are not enough Sun Hours in a day to complete 3 stages. So i am not really sure what you are driving at.

        Al PWM controllers work the same by modulating the Pulse Width Duty Cycle. At 100% modulation the MOSFET is turned on connecting the panel directly to the battery forcing the controller to act as Constant Current Source. When the battery voltage reaches a Set Point, then the controller switches and behaves as a Constant Voltage source for the last two stages modulating the Pulse Width by turning the MOSFET On/Off duty cycle less than 100%.

        Inn most applications you are better off not using any controller if you want to use PWM controllers. All you need is a diode to prevent the panel from back feeding the panel after sunset. That keeps the panel in CC mode to deliver all the power it can. Only time a Solar really stands a chance of fully charging batteries is in Summer. Problem is 90% of folks do not have enough panel wattage to ever fully charge a battery. In that case one should use a MPPT Controller with all 3 stages set to 16 volts for each 12 volts of battery. That forces the controller to stay in BULK mode or Max Smoke all day to get the battery charged up as much as possible. Then once a week use generators to saturate the battery on a 12 hour run.
        thanks sir for the answer ...

        but diode is not enough..constant current is not good for battery charging ...only in the first stage where if put voltage source and the battery have so low resistance it will swallow

        up the current in great amounts and will self-destory it self


        that is why current source guarantee that battery can never EAT current more than it should at that stage ...the fact that current is flowing fast at that stage can produce gasing and many other bad things in battery

        at the end going with current source will easily exceed the battery "full state " voltage ...and we need some sort of stopping the fast charging process

        voltage mode comes in ...the battery at that state have high resistance offering it a voltage wont damage it , it will only draw small amounts of current

        at end of this cycle battery will only draw very very small amount at that point pwm controller

        will go to float mode "it is now convicned" that battery have taken all it can flaot is 13.5 and it will stay there almost forever



        my main question was replied by you indirectly .......hanging scope in the gate of mosfet will reveal is controller in hand is pwm or on-off

        one have to be patient with it because pwm takes palce in final stages



        it remains to be seen if i can know what controller can make real battery current measurements at pwm voltage mode charging and stop charging when battery draw none

        from the ones that actually not sensing the current but enter the pwm stage and stay there for 1 hour and then quit charging ...yes some charging logarithms are using this plan


        here is pdf for solar controller where the manual says that charging logarythem do not test current just HOPS to float after one hour of pwm



        i find it critically important that we understand what are those chinese guys are making to us ...and whether thier charging logarthem is 100% accurate or not


        thier 10usd controllers are controlling the life of hour 250usd worth of agm deeep cycle batteries!!!!!!!!!!!!!!!!











        Attached Files

        Comment


        • #5
          All I can say is you do not know much about solar. 90% of all solar battery systems cannot replace what is used in a day. Thus you never get out of constant current mode. In that case a controller is a waste of money unless it is a MPPT controller which is a Power Converter not voltage. All PWM controllers are voltage converters. When at 100% duty cycle are pure constant current sources.

          There is no such thing as three stages. It is two stages or more correctly two voltage set points of Absorb roughly 14.6 volts, and Float of roughly 13.6 volts. Absorb is not a timed event, it is a current event and ends when current taper to 3% of C, There are not enough hours in a day to get to that point. So they cheat and make it a timed event.

          There are two bad things you can do to a battery, and one is worse then the other.

          1. The worse thing you can do is undercharge a battery which is 90% of all solar system failures, and it happens quickly in less than 2 or 3 years
          2. Is over charging and only happens moistly in car batteries in vehicles using a CV 14.2 volts the industry standard and gets you 3 to 5 years of use. The others are from AC chargers set to high using the so called 3-Stage charging.

          The best charging method used by all utilities is Float Charging at a fixed voltage of roughly 2.2 to 2.5 volts per cell which can yield 10 years of service.

          If you look at the top tier battery manufactures for Solar systems like Trojan has completely changed there charging recommendations. For Solar users they recommend what they call Daily Charge or Bulk charge of a simple CC/CV of 14.82 volts on a 12 volt battery. Bottom line is you want to error on the over charge side of the razor blade for maximum battery life with respect to Pb batteries.
          MSEE, PE

          Comment


          • #6
            Originally posted by Sunking View Post
            All I can say is you do not know much about solar. 90% of all solar battery systems cannot replace what is used in a day. Thus you never get out of constant current mode. In that case a controller is a waste of money unless it is a MPPT controller which is a Power Converter not voltage. All PWM controllers are voltage converters. When at 100% duty cycle are pure constant current sources.

            There is no such thing as three stages. It is two stages or more correctly two voltage set points of Absorb roughly 14.6 volts, and Float of roughly 13.6 volts. Absorb is not a timed event, it is a current event and ends when current taper to 3% of C, There are not enough hours in a day to get to that point. So they cheat and make it a timed event.

            There are two bad things you can do to a battery, and one is worse then the other.

            1. The worse thing you can do is undercharge a battery which is 90% of all solar system failures, and it happens quickly in less than 2 or 3 years
            2. Is over charging and only happens moistly in car batteries in vehicles using a CV 14.2 volts the industry standard and gets you 3 to 5 years of use. The others are from AC chargers set to high using the so called 3-Stage charging.

            The best charging method used by all utilities is Float Charging at a fixed voltage of roughly 2.2 to 2.5 volts per cell which can yield 10 years of service.

            If you look at the top tier battery manufactures for Solar systems like Trojan has completely changed there charging recommendations. For Solar users they recommend what they call Daily Charge or Bulk charge of a simple CC/CV of 14.82 volts on a 12 volt battery. Bottom line is you want to error on the over charge side of the razor blade for maximum battery life with respect to Pb batteries.


            it is really confusing is 3 stages charging have no meaning then why hundereds of websites is making alot of advs about it claiming that thier chargers are utilizing

            this technology ......current charging is bad BY EXPERIENCE i have chinese charger from suoer company

            they claim it is 3 stage ....and i do have a bettery ..deep cycle one

            this battery was hooked to pwm 3 stage charger the battery is fine and once charger i can test it it gaves 13.4 solid


            after this battery was removed ....though i have not used it just kept cahrging it from time to time ...the battery now with that chinese "current mode"

            charger have lost its capacity now can not raise more than 13 volt


            so sad in 6 months the batttery lost all this due to a lying chinese factory that was promising us a 3 stage chagger


            but found to be just a crappy current mode


            i have discover that it is current mode ....because voltage was rasing gradually till 14.2 then the charger shutdown immediately as soon as battery voltage is 14.2


            the battery ofcourse will get discharger in seconds to 13 volt solid ....if it was 3 stage it would have stayed at 14.2 volt for some time (the is transition from current mode to pwm )

            and then after a it should have changed to 13.5 vdc .....however it never done so

            so basically it is piece of "shiiii-----"


            i really tend to trust experience rather than "guess"


            i will attach pictures during tests of prove of how those chinese are selling us bad products

            Attached Files

            Comment


            • #7
              Gendi the problem is you bought Chi-Com counterfeit junk. You got what you paid for. I hate seeing that happen to people. You should have known something was wrong from the price you paid. 3-Stage charging is just a Marketing term used to describe what it does. In the end it is just a CC/CV charger that has 2 voltage set points under some means of automated control.
              Last edited by Sunking; 01-28-2017, 12:58 PM.
              MSEE, PE

              Comment


              • #8
                true ...i just hate the part where manufactures use marketing terms ....while giving us the "salt"....they should have said "charger"
                not .3 satge ...any way it is not about "you get what you pay for"....as we have always to look for best bargins and expensive does not guarantee quality

                when we fail in finding good quality cheap item my duty is to warn the others ....now i am sure to youtube it

                those suoer company are just making alot of advs about their products ...to be honest i have pwm solar from them that is just 5 star cheap and working "3 stage100% confirmed"

                but there 3 stages ac dapater is lousy ......just wonder it is not rocket-scince to make one

                current source and at the end make it a voltage charging source ....yet they have failed ....what really perplex me is why they make good in their CHEAP solar controller AND confuse it

                in thier AC charger



                after i make too many reviews and tear down to those units i will you tube it and give you link for this thanks

                Comment


                • #9
                  Would you like to buy a 4 stage charger ? I can look and find one. Just open your wallet.
                  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


                  • #10
                    Originally posted by gendil View Post
                    true ...i just hate the part where manufactures use marketing terms ....while giving us the "salt"....they should have said "charger"
                    not .3 satge ...any way it is not about "you get what you pay for"....as we have always to look for best bargins and expensive does not guarantee quality
                    The Devil is in the specs. If you know how to read them and interpret them will tell the tale.

                    MSEE, PE

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