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Thread: Do i need more then 1 diode, which kind how

  1. #1

    Default Do i need more then 1 diode, which kind how

    AS YOU GUYS KNOW I HAVE 12....10 WATT PANELS, DOES EACH PANEL NEED A DIODE

    I HAVE 6 IN PARALLEL AND 6 IN PARRNELL THEN IN SERIES TO 4 BATTERIES

    i ONLY HAVE A DIODE ON WIRE COMING FROM SOLAR PANEL, THAT ALL, WERE DO I NEED DIODES IF I NEED MORE..

    SOME GUY SAID SINCE MY PANELS ARE IN SERIES IF ONE GETS A LITTLE SHADE THEN THE OTHER PANEL WILL FEED THE WATTS TO THE ONE IN THE

    SHADE AND SO ON...


  2. #2

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    You can connect one diode parallel with one 10W module. Then you will have less shadow problem.

  3. #3

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    Quote Originally Posted by indalecio.feng View Post
    You can connect one diode parallel with one 10W module. Then you will have less shadow problem.
    Thanks, I already went on ebay and ordered me 25 diodes, 1$ more then the price of 10 pcs, since I wanted them in 3 days or so, I had to buy them from a usa dealer, instead of a hong kong 2-3 week delivery time..

    I did some test with my other solar panels and used 8 diodes and everything went well, so I will wait for these to get here and wire them all up...

  4. #4
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    I'm not sharp on electricity, but when I installed my diode, I checked my voltage and it went down from 16 to 1. I reversed the diode and it went back to the correct voltage. Apparently ( a least on mine) there is a front and back to a diode.

    Maybe someone can tell me if I'm right. Thanks

  5. #5
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    Quote Originally Posted by scheek View Post
    I'm not sharp on electricity,
    You need to educate yourself a bit, even 1 battery can store enough power to ruin your day if you make a mistake.


    but when I installed my diode, I checked my voltage and it went down from 16 to 1. I reversed the diode and it went back to the correct voltage. Apparently ( a least on mine) there is a front and back to a diode. Maybe someone can tell me if I'm right. Thanks
    Yes, there is a front/back Fwd/rev on a diode.

    There are also voltage ratings and Amp ratings. Often, they can be burned out in an instant, and still look the same.
    Wikipedia has a bit of an article about them
    http://en.wikipedia.org/wiki/Diode

    for solar use, Schottky diodes have less losses than regular diodes
    Last edited by Mike90250; 10-14-2009 at 10:32 AM.
    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. #6

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    I bought me the Schottky diodes , they are 40 volt and 3 amps, got 25 pcs for $5 shipped to me in 3 days, cheaper if you wait from Hong Kong but I needed them now...

    So far the little 10 watters are holding up good...

  7. #7
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    My workplace computer had your sketch blocked, I've just now seen it here at home.

    > I HAVE 12....10 WATT PANELS

    So that's 120W, @ 24V = 5 amps at full power. That will not make 3A diodes happy
    Semiconductors are pretty unforgiving about abuse.
    So if we factor in about 20% expected system losses, that takes your 5A down to 4A, which the diodes may tolerate.

    If you use a decent charge controller (Trace C-12) that has a blocking diode in it, and you don't need to add one.

    You also should have a FUSE in your system, in case a wire gets nicked or pinched, you don't get a fire starting. 6A in the PV string should work. The fuse is to protect the wire from burning, not the devices. Depending on your loads, and the wires, you need to fit the right fuse for the wire.
    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

  8. #8

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    Quote Originally Posted by Mike90250 View Post
    My workplace computer had your sketch blocked, I've just now seen it here at home.

    > I HAVE 12....10 WATT PANELS

    So that's 120W, @ 24V = 5 amps at full power. That will not make 3A diodes happy
    Semiconductors are pretty unforgiving about abuse.
    So if we factor in about 20% expected system losses, that takes your 5A down to 4A, which the diodes may tolerate.

    If you use a decent charge controller (Trace C-12) that has a blocking diode in it, and you don't need to add one.

    You also should have a FUSE in your system, in case a wire gets nicked or pinched, you don't get a fire starting. 6A in the PV string should work. The fuse is to protect the wire from burning, not the devices. Depending on your loads, and the wires, you need to fit the right fuse for the wire.
    I have 2 batteris in series, then 2 batteries in series, then the wire to put them in parallel I added a fuse, the power cable that goes to my 900 watt inverter also has a 20 amp fuse for the mean time, I only run 100 watts max...

    the solar panels to my charge controller have a 15amp fast blow fuse and from charge controller to battery I also added a 15 amp fast burn fuse..

    the 3 amp diodes are being used per panel, I think that's what I understood for another person...I have 2 10w panels in series then a diode on the power side, and so on for each of the pair of 10 watt panels....so when some panels get shade they would get charged by other panels, I have a 10a recifier diode on cable that goes to charge controller and I will use a 10a diode but the other more efficent type, have less voltage drop..

    I added all fuses on last night, after 1 week of thinking every day, what if...all wire connections are 8 and 4 gauge on battery to inverter..from charge controller and solar panel they are like 12-16 guage

  9. #9

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    Yes, right! Should be one diode per panel.

    For the fuse I think should be ok.

    And please send your result or some pics after you finish the installation.

    Quote Originally Posted by 4321loco View Post
    I have 2 batteris in series, then 2 batteries in series, then the wire to put them in parallel I added a fuse, the power cable that goes to my 900 watt inverter also has a 20 amp fuse for the mean time, I only run 100 watts max...

    the solar panels to my charge controller have a 15amp fast blow fuse and from charge controller to battery I also added a 15 amp fast burn fuse..

    the 3 amp diodes are being used per panel, I think that's what I understood for another person...I have 2 10w panels in series then a diode on the power side, and so on for each of the pair of 10 watt panels....so when some panels get shade they would get charged by other panels, I have a 10a recifier diode on cable that goes to charge controller and I will use a 10a diode but the other more efficent type, have less voltage drop..

    I added all fuses on last night, after 1 week of thinking every day, what if...all wire connections are 8 and 4 gauge on battery to inverter..from charge controller and solar panel they are like 12-16 guage

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