How Do I Connect 12v Panels with MC4 Connectors ?

KnowledgeSponge
KnowledgeSponge Solar Expert Posts: 173 ✭✭✭
in Solar Beginners Corner #1
I now have 4, 100Watt 5.68A Solar Panels.

My battery bank is 12v.

My Inverter is 12v


What's the best way to connect my panels?

Since I need 12v, I connect them in Parallel...right? (If I connect them in Series, the voltage goes up..right?)
Don't I want the Current to increase, not the Voltage?

If so, are there MC4 adapters to do this easily w/o having to make wires and connectors sets myself?

Should the wiring that came with the solar panels be sufficient to handle the additional current?
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: How Do I Connect 12v Panels with MC4 Connectors ?

    If you are using A PWM controller then yes they must be in parallel. When you put four in parallel they need circuit protection on each. So you are looking at the need for a combiner box:
    http://www.solar-electric.com/sopawiinco.html

    Someone on this forum made their own for a small system. Can't remember who.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #3
    Re: How Do I Connect 12v Panels with MC4 Connectors ?

    typically you want to connect 3 or more panels thru a combiner box.

    With a small hobby or RV system you might look for a fused distribution block, a cheap alternative which will give you some elevated security.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #4
    Re: How Do I Connect 12v Panels with MC4 Connectors ?

    To connect your panels, buy one of these in the length you need and cut it in half, that gives you a M & F connector.

    http://www.solar-electric.com/incaforsoelp.html
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #5
    Re: How Do I Connect 12v Panels with MC4 Connectors ?
    Cariboocoot wrote: »
    Someone on this forum made their own for a small system. Can't remember who.

    I think that 'ywhic' built one from QO breakers. I don't think that they are rated for a 48 volt system. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #6
    Re: How Do I Connect 12v Panels with MC4 Connectors ?

    FWIW,

    Yes, ywhic, who seems to have been absent here for quite some time, like some othere here did build a Combiner Box using Square D QO series breakers. These breakers are rated for DC -- single pole, only with ratings exceeding 10 A through 70 A on systems up to 48 V nominal, but are rated only at 5,000 AIC -- from a 2008 spec).

    The OP states that the system in question is 12 V nominal. YMMV, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • KnowledgeSponge
    KnowledgeSponge Solar Expert Posts: 173 ✭✭✭
    #7
    Re: How Do I Connect 12v Panels with MC4 Connectors ?

    Ok, so if I'm understanding.....

    I would buy extension MC4 cables approximately twice the distance I need (say I need 15ft, buy a 30ft cable)
    then cut it in the middle. Do this for each Solar panel then run all those leads to the junction block....
    Connecting all negativs together and all positives together.

    Is that correct and is this a suitable junction block (providing it is rated for the Amps I will be dealing with)?

    SolarJunction05052013_zpsac7b5189.jpg

    Oh wait...this Junction block is only rated for 10A ??
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #8
    Re: How Do I Connect 12v Panels with MC4 Connectors ?
    KnowledgeSponge wrote: »

    Oh wait...this Junction block is only rated for 10A ??

    A junction block with diodes in it (bypass diodes) is designed to be the output of a home built panel, not for combining the wires from multiple panels.
    A combiner for more than two strings will need to have a place for fuses or circuit breakers for each individual string of panels.
    SMA SB 3000, old BP panels.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #9
    Re: How Do I Connect 12v Panels with MC4 Connectors ?
    KnowledgeSponge wrote: »
    Ok, so if I'm understanding... ..Is that correct and is this a suitable junction block ...

    NO, you don't need a junction box, you need a combiner box, links were provided by myself and 'Coot, you might check them out! ...also 'code' requires fuse or breakers for each string. In the past it wasn't uncommon to just combine the panels in a power distribution block.

    Attachment not found.

    Code requires UL listed combiner boxes which links were provided. If it's a hobby system or not worrying about code but you would like the safety of fuses. You could use a fused power distribution block (I hear an echo) in a 12 volt system you might use a simple car fuse type ATC or Car stereo which use AGU
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • KnowledgeSponge
    KnowledgeSponge Solar Expert Posts: 173 ✭✭✭
    #10
    Re: How Do I Connect 12v Panels with MC4 Connectors ?

    "CombinerBox"

    Funny, that word was so foreign to me I don't think my brain even detected it.

    Attentional bias – the tendency to pay attention to emotionally dominant stimuli in one's environment and to neglect relevant data, when making judgments of a correlation or association.
    Ambiguity effect – the tendency to avoid options for which missing information makes the probability seem "unknown
    Choice-supportive bias – the tendency to remember one's choices as better than they actually were
    Confirmation bias – the tendency to search for or interpret information or memories in a way that confirms one's preconceptions

    Guilty.

    ;)

    Thx

    Now I see. Sometimes when you don't understand something, you can search and search, and still not see.
    When the day comes I know what I'm doing, I'll remember that when the new guy is asking questions.
    There are a bunch of really helpful people at this forum and you're appreciated.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #11
    Re: How Do I Connect 12v Panels with MC4 Connectors ?
    KnowledgeSponge wrote: »
    "
    Attentional bias – the tendency to pay attention to emotionally dominant stimuli in one's environment and to neglect relevant data, when making judgments of a correlation or association.
    Ambiguity effect – the tendency to avoid options for which missing information makes the probability seem "unknown
    Choice-supportive bias – the tendency to remember one's choices as better than they actually were
    Confirmation bias – the tendency to search for or interpret information or memories in a way that confirms one's preconceptions

    Looks like somebody squeezed the KnowledgeSponge and a lot of Knowledge poured out. Thanks! :-)
    SMA SB 3000, old BP panels.
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  • CDN_VT
    CDN_VT Solar Expert Posts: 492 ✭✭✭
    #12
    Re: How Do I Connect 12v Panels with MC4 Connectors ?

    I call that the DUH Factor !
    And it happens on this site , and many other techie sites ..
    None to worry , as long as those who know,,,,, realize the DUH / Brain fluff wall !!

    I needed to see that on a ground clamp / electrolysis / and choice of metal question , then were the REG's..

    It's always better to ask , even simple questions , because once the brain clicks in on the correct path , then the reasoning becomes simpler.
    There are always questions , :cool:

    VT
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  • KnowledgeSponge
    KnowledgeSponge Solar Expert Posts: 173 ✭✭✭
    #13
    Re: How Do I Connect 12v Panels with MC4 Connectors ?
    inetdog wrote: »
    Looks like somebody squeezed the KnowledgeSponge and a lot of Knowledge poured out. Thanks! :-)

    ;)

    One has to consider that before it absorbs knowledge, the "knowledge sponge" COULD be technically...."the Idiot sponge"....lol
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  • KnowledgeSponge
    KnowledgeSponge Solar Expert Posts: 173 ✭✭✭
    #14
    Re: How Do I Connect 12v Panels with MC4 Connectors ?
    CDN_VT wrote: »
    I call that the DUH Factor !
    And it happens on this site , and many other techie sites ..
    None to worry , as long as those who know,,,,, realize the DUH / Brain fluff wall !!

    I needed to see that on a ground clamp / electrolysis / and choice of metal question , then were the REG's..

    It's always better to ask , even simple questions , because once the brain clicks in on the correct path , then the reasoning becomes simpler.
    There are always questions , :cool:

    VT

    Thx.
    I had been reading up on Solar stuff, but I just think the CONCEPT of a combiner box wasn't clicking.

    I was stuck on thinking there MUST be a way to attach all these panels together using the MC4 connectors.
    But that would be in series.

    Well, now I understand perfectly. So, I'm a little bit less of a solar idiot than I was yesterday :cool:
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #15
    Re: How Do I Connect 12v Panels with MC4 Connectors ?
    KnowledgeSponge wrote: »
    Well, now I understand perfectly. So, I'm a little bit less of a solar idiot than I was yesterday :cool:

    We all are and once we think we have a handle on 'it all' we can take a peek at the Midnite forum, suggested ideas and look into some creative minds thinking up all sorts of new things...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #16
    Re: How Do I Connect 12v Panels with MC4 Connectors ?
    KnowledgeSponge wrote: »
    I was stuck on thinking there MUST be a way to attach all these panels together using the MC4 connectors.
    But that would be in series.
    Just for grins, I will point out that you can get MC4 wye connectors or wye harness adapters. By putting those in cascade separately at the + and - sides you could make any parallel combination you wanted. But you would have to interrupt each line somewhere before the wye to put a fuse on it. Result, the combiner box wins again.
    SMA SB 3000, old BP panels.
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