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Thread: Solar Charge Controllers - Multiples

  1. #21
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    Quote Originally Posted by billvon View Post
    No. In engineering terms, all MPPT controllers are "buck" converters - they reduce output voltage while increasing current. They do not boost voltage.
    That is mostly true but there are a few high end manufactures like Mid Night Solar that have buck/boost built into 1 controller. The Boost range is very limited, and when operated in Boost are very inefficient. So i would never recommend anyone operate in a boost range. For a 48 volt battery your minimum panel Vmp should be 62 volts. This will be the point where most quality MPPT controllers are most efficient on a 48 volt battery system.
    MSEE, PE

  2. #22
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    Quote Originally Posted by Sunking View Post
    That is mostly true but there are a few high end manufactures like Mid Night Solar that have buck/boost built into 1 controller. The Boost range is very limited, and when operated in Boost are very inefficient. So i would never recommend anyone operate in a boost range. For a 48 volt battery your minimum panel Vmp should be 62 volts. This will be the point where most quality MPPT controllers are most efficient on a 48 volt battery system.
    That would be great; a boost mode would help a lot when using odd-sized panels (i.e. 48/96 cell panels) on off-grid systems. The last Classic manual I saw had this note:

    "Boost Charge Mode (Lower to Higher Voltage, Unimple-mented as of May 2011)"

    Have they since implemented this?

  3. #23
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    Quote Originally Posted by billvon View Post
    That would be great; a boost mode would help a lot when using odd-sized panels (i.e. 48/96 cell panels) on off-grid systems. The last Classic manual I saw had this note:

    "Boost Charge Mode (Lower to Higher Voltage, Unimple-mented as of May 2011)"

    Have they since implemented this?
    I believe so. They make them right here in TX and i have a couple of sample units to play with. Honestly I have not tried them in Boost Mode as it is not something I would ever implement becuase of the efficiency issue. Besides the Boost range is very small, something on the order of 50 volts on a 48 volt battery system. I am not willing to go there.
    MSEE, PE

  4. #24

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    Hi All

    For my solar system, I am a bit confused about the terminologies used for inverters ... (off-grid, grid-tie)

    In where am located, (India) selling back the power to grid is not an option ..

    So I am looking for an inverter which serves dual purpose :

    1) Converting DC to Ac to supply power to my house
    2) Converting Power Supply AC to DC to charge my batteries. That is batteries could get charged both from PV and/or Power Supply.
    I believe every inverter is equipped with a rectifier/charger to do this.

    And, more importantly - I would like an auto-switch over from the Battery to Power/Mains when Battery is Low and
    from Mains to Battery when power supply is cut (there are huge power cuts in our zone). Precedence to be given to battery
    power, if available. Can such setup be possible?

    Thanks in anticipation!!

  5. #25
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    Quote Originally Posted by solarponders View Post
    ...
    My mppt vendor tells me there is a tweak that can be done to set the battery
    input voltage to 24v and output to 48v. Does that make sense? Not to me, at least.
    not to me either. If your vendor cannot show you a system working as he described, I bet it does not exist. Sorry.

    To run a 48 v inverter, you need 48V

    You would need a new charge controller at the very least, and a 48V battery bank of course.


    To interact with the grid, I know the XW series of inverters will do that, and I think Outback has a model that can also.

    The xw-6048 that I have, has the transfer relays built in, and a grid AC input/output (it has a No Sell mode) and a 2nd AC input for a 240VAC generator . And an internal battery charger.
    Since the dawn of time it has been mankind's dream to blot out the sun.
    Montgomery Burns

    "Always listen to experts. They'll tell you what can't be done and why. Then do it."

    spreadsheet based voltage drop calculator:
    http://www.solar-guppy.com/download/...calculator.zip
    http://www.solarpaneltalk.com/showth...oss-calculator

    http://www.mike-burgess.org/PVinfo_2.html

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,
    battery lugs http://tinyurl.com/LMR-BigLug
    Setting up batteries http://tinyurl.com/LMR-NiFe

    gear :
    Powerfab top of pole PV mount | 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 || || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

  6. #26
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    Quote Originally Posted by solarponders View Post
    So I am looking for an inverter which serves dual purpose :

    1) Converting DC to Ac to supply power to my house
    2) Converting Power Supply AC to DC to charge my batteries. That is batteries could get charged both from PV and/or Power Supply.
    I believe every inverter is equipped with a rectifier/charger to do this.
    These certainly exist but not every inverter does this. You need an inverter/charger. For example the Prosine 1800 does not have a charger but the Prosine 2.0 does.

    And, more importantly - I would like an auto-switch over from the Battery to Power/Mains when Battery is Low and
    from Mains to Battery when power supply is cut (there are huge power cuts in our zone). Precedence to be given to battery
    power, if available.
    Yes. The old Trace SW series did this. I THINK the Outback series of inverters will do this as well.

    However, this is not the best use of batteries. If you have a grid and can do grid intertie it is much better to run off the grid and reserve your batteries for backup power. One, they will last a lot longer. Two, if you are always discharging your batteries they will be dead when you need them.

  7. #27

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    Does anyone have experience with thin film solar panels? I ran into one resller, where the cost quoted
    per watt of the panel is 2/3rd of the regular (mono/poly) .. here is the product data sheet.

    http://www.nanosolar.com/sites/defau...NSC-001_12.pdf

    Not sure, if this is a new breakthrough in the technology (by German) that has brought a significant drop in the
    panel price or just an experimental thingy ...

  8. #28
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    Quote Originally Posted by solarponders View Post
    Does anyone have experience with thin film solar panels?
    Yes runaway, do not walk. They are like DIY panels and will be useless in 5 years or less.
    MSEE, PE

  9. #29
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    Quote Originally Posted by Sunking View Post
    Yes runaway, do not walk. They are like DIY panels and will be useless in 5 years or less.
    Nano Solar - Aren't they one who has been promising the world and delivered very little or nothing for years now -

  10. #30
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    Quote Originally Posted by solarponders View Post
    Does anyone have experience with thin film solar panels? I ran into one resller, where the cost quoted
    per watt of the panel is 2/3rd of the regular (mono/poly) .. here is the product data sheet.

    http://www.nanosolar.com/sites/defau...NSC-001_12.pdf

    Not sure, if this is a new breakthrough in the technology (by German) that has brought a significant drop in the
    panel price or just an experimental thingy ...

    I can't give you advice for the present sales but below is a link to information new to the market today and pretty amazing I think;


    http://cleantechnica.com/2012/03/14/...eanTechnica%29

    Hope the link works it's long !
    1.6Kw of PV, Outback FM80 controller, 40A PWM cheap Chinese controller, 12V 1000 AH of Trojan T105RE batteries, 2.5Kw Aims MSW inverter and 400W TSW inverter.

    I will respect other peoples threads and try to stay ON TOPIC. Equally if I start a thread, and in order to keep forum friction to a minimum, only constructive ON TOPIC responses will be answered. Should I still don't reply: It is likely I have blocked you. for being B.A.D. (Belligerent And Derisive)

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