MPPT controller question

icarus
icarus Solar Expert Posts: 5,436 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
I have an MPPT question that I confess I should know the answer to, but as I (over) think it now I am not sure.

Say you have a small array, so say 6 12 vdc panels. If you wire these panels in three sub arrays of two panels each. (Wired to 24 vdc to a MPPT controller) Now let's suggest that one (or two of) of the sub arrays gets shaded, how does the controller handle the drop? I assume that the controller would handle the drop such that the only net loss would be from the sub array that is shaded?

Am I right, in general terms?

Tony

PS This is my system, currently wired for 12 volts in/out, and I am considering wiring the Pv to 24vdc for greater MPPT performance and lower line loss.
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Comments

  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #2
    Re: MPPT controller question

    That's a good question. If the tracking of the MPPT controller is any good, it will just find the best Max Power Point it can and operate there. Your scenario is fairly simple though, compared to how bad it could be if each string contained even more than 2 modules in series.

    Depending on the complexity of the shading situation, the controller might have a few max power points to choose from. This is the fun part of controller design,, I think.

    boB
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  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    #3
    Re: MPPT controller question

    This paper might be of interest.
    GP
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #4
    Re: MPPT controller question
    GreenerPower wrote: »
    This paper might be of interest.
    GP


    Yep... THAT'S what I'm talking about !

    I think I have that paper too somewhere.

    boB
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #5
    Re: MPPT controller question

    BTW, the MX60 did a very good job with this type of issue.

    R.I.P MX60

    boB


    PS... Would love to know the brand names of those 13 inverters in that article, GP.
    Maybe we could find that out ??
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #6
    Re: MPPT controller question

    boB, how will the Classic perform under these type of conditions?

    Eric
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #7
    Re: MPPT controller question
    westbranch wrote: »
    boB, how will the Classic perform under these type of conditions?

    Eric

    I am trying very hard to make certain it will track these conditions very well. I have some tricks up me sleeves. This is very important. Thanks for asking !

    And, It's is coming right along. New latest and greatest PCBs are here and being worked on as we type. Breaks over. Back 2 it !

    boB
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,945 ✭✭✭✭✭✭
    #8
    Re: MPPT controller question

    boB,

    I know harvest is everything but to the small .1%? of the world that is offgrid I would like to plug just having the controller smart enough to pick a voltage that keeps outputting power. At least have it lie to me and tell me that it is.... RIP MX-60
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #9
    Re: MPPT controller question

    Dave I am curious about your comment on the MX60... can you expand on

    "just having the controller smart enough to pick a voltage that keeps outputting power"

    thanks
    Eric
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #10
    Re: MPPT controller question
    westbranch wrote: »
    Dave I am curious about your comment on the MX60... can you expand on

    "just having the controller smart enough to pick a voltage that keeps outputting power"

    thanks
    Eric

    Nevermind... I won't get into it. (i.e. edited)

    boB
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,945 ✭✭✭✭✭✭
    #11
    Re: MPPT controller question

    Ah edits, certainly not trying to offend one of the great ones but rather a plug for refinement of design that never happened out the backdoor.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #12
    Re: MPPT controller question
    Dave Sparks wrote: »
    Ah edits, certainly not trying to offend one of the great ones but rather a plug for refinement of design that never happened out the backdoor.

    Didn't offend me... :D I think I know what controller you were talking about, Dave.

    boB
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,945 ✭✭✭✭✭✭
    #13
    Re: MPPT controller question

    Good! we're cool! I know that MX changed everything for me and for many years it was in my top ten "enablers for good life on your own grid"
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    #14
    Re: MPPT controller question

    and the Classic will be even better then the MX60 so it should be in the top 2 or 3 things to make life better.
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #15
    Re: MPPT controller question
    "...and the Classic will be even better..."
    We keep hopin'... Check this post from July, 2006:

    http://forum.solar-electric.com/showpost.php?p=1305&postcount=10

    Regards,
    Jim / crewzer
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  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    #16
    Re: MPPT controller question

    Well I know we are all waiting patiently but I can say they work I do have 2 here that have been running for almost a year. This controller is not easy to build boB has been working hard and has really outdone himself the features are amazing. I will attempt to list a few.

    *Up to 250 volts dc input, safe to close to 300
    *Switchable between solar, wind or hydro
    *It talks
    *Truly stackable so 1 controller takes charge
    *Boost Mode
    *Snow Melt feature
    *User upgradable software
    *2 aux outputs one can be configured as an input
    *User interface for setup walks the user threw the programming

    There are many more features and I am sure boB will chime in with any I have missed. All in all this will be a revolutionary new piece of equipment and will prove worth the wait.
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  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    #17
    Re: MPPT controller question

    I almost forgot we have a few live beta sights logged as well check them out

    http://data.aprsworld.com/sites/midnite/maine/
    This is my system The wind turbine is an 800 watt other power design we will have the solar live soon as well beside an FM60 and an XW60


    http://data.aprsworld.com/sites/midnite/montana/
    This is Logan's system it is a prototype bergey 48 volt turbine


    http://data.aprsworld.com/sites/midnite/washington/
    This one is real fun it is a high voltage classic that was running in the area of 265 volts dc last winter

    http://data.aprsworld.com/sites/midnite/hawaii/
    Rick in Hawaii


    http://data.aprsworld.com/sites/midnite/oregon/
    Jason's he is running a version of the other power turbine as well
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  • boB
    boB Solar Expert Posts: 1,032 ✭✭✭✭
    #18
    Re: MPPT controller question
    crewzer wrote: »
    We keep hopin'... Check this post from July, 2006:

    http://forum.solar-electric.com/showpost.php?p=1305&postcount=10

    Regards,
    Jim / crewzer

    OK, Jim ! Rub it in real good !! :D
    Actually, I was only able to devote part time to this project for 3 of those years since I had to have that day job, so I don't feel ~too~ bad.
    But, we're gettin' there now, though since I (and others) are full time on this thing.

    It was great seeing you down at sunny SPI in Anaheim, Jim !

    Here's a profile pic of Jim and 2 other industry friends and my Hotel room lab setup. No rest on this stuff.

    boB
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #19
    Re: MPPT controller question

    Just some friendly elbowing and hopefully a dash of motivation! :p Great seeing you as well, boB... thanks for the great pic of me with Tom and Boe Duffy of The Solar Biz!

    Regards,
    Jim / crewzer
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,945 ✭✭✭✭✭✭
    #20
    Re: MPPT controller question

    The boyz at X are working also and we all benefit from competition!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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