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Thread: wiring for off grid system

  1. #1
    Junior Member
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    Default wiring for off grid system

    Hello,
    I've done a lot of reading online and have a good basic understanding of off grid systems, but can't find any detailed wiring diagrams. We'd like to do everything ourselves, and then just pay an electrician to check it for us. I have some specific questions though please, and welcome any advice from the nice folks out there that seem to know a lot.

    System will be 10 x 80 watt panels, in parallel, about 4 amps ea, a 50-60 amp charge controller, about 2000ah of batteries, and a 4-5000w inverter. I understand how to size the wires based on distance.

    questions:
    1. Does anyone have a detailed wiring diagram? Like a diagram for idiots?
    2. Do I need fuses? Which size and where exactly?
    the panels have mc4 cables on them. I plan to connect needed wire to each one with mc4 connectors, (so I don't have to cut off the connectors and void my warranty) and connect all the positive and negative wires to a combiner box, and then to the charge controller.
    3.how should the system be grounded?

    Thanks!

  2. #2
    Solar Fanatic
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    Default

    Quote Originally Posted by Bill View Post
    questions:
    1. Does anyone have a detailed wiring diagram? Like a diagram for idiots?
    2. Do I need fuses? Which size and where exactly?
    the panels have mc4 cables on them. I plan to connect needed wire to each one with mc4 connectors, (so I don't have to cut off the connectors and void my warranty) and connect all the positive and negative wires to a combiner box, and then to the charge controller.
    3.how should the system be grounded?

    Thanks!
    No offense dude but you have no business trying to DIY this project, you are asking to burn down your property or electrocute you or someone else.
    MSEE, PE

  3. #3
    Administrator
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    Default

    Quote Originally Posted by Sunking View Post
    No offense dude but you have no business trying to DIY this project, you are asking to burn down your property or electrocute you or someone else.
    Thank you for the above response
    Rich
    WWW.solarsaves.net

    NABCEP certified Technical Sales Professional

    http://www.solarpaneltalk.com/showth...Battery-Design

    http://www.calculator.net/voltage-drop-calculator.html (Voltage drop Calculator among others)

    www.gaisma.com

  4. #4
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    Hi Bill - Welcome to Solar Panel Talk!

    We would encourage you to work with someone who is qualified to do electric design and have an electrician do the actual connections.

    There is a lot of the work that you can manage is you are reasonably good at DIY such as the mounting etc.

    The electrical connections are where things can get sticky if they are not done right.

    Russ

  5. #5
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    Default

    Quote Originally Posted by Sunking View Post
    No offense dude but you have no business trying to DIY this project, you are asking to burn down your property or electrocute you or someone else.
    Quote Originally Posted by Naptown View Post
    Thank you for the above response
    Naptown - can you provide a response for the OP ? I mean you are a solar contractor, and have a license, and any advice you provide, you will be on the hook for.

    Sadly, this is the result of too many scam "Free solar power" $49.99 eBooks. It's not like doing you car brakes at home, or changing the blade on your lawnmower.

    More like wireing a 480V transformer into a new addition of your house, and the battery bank is more like a carton of acid with a stick of TNT in it. Not something you can learn from a few posts off the internet.

    Peruse the photos in my .sig, there is a permitted system diagram there, it will give an idea of what's involved.

    And if you don't understand why you tape your tools before working on the batteries, the answer "To prevent accidental shorts" means nothing if you don't understand what a short circuit is, and why batteries and wrenches are in-compatible.
    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
    GreenPowerVideos
    Guest

    Default The answer to your questions

    Hi-

    Well, you are in the normal dilemma. People have a little information, but the critical info is missing. That is because you can't learn how to do this from youtube videos. You'll land up "letting all the smoke out of your electronics". We engineers know that they put smoke inside electronic components- and if you let it out, they stop working!

    I'll be the voice of reason here and tell only the truth.

    There are several ways to wire your panels.. and you have to calculate the voltage output you want them to put into the system by determining: the length of the run from the panels to the charge controller, the controller's maximum voltage input, and the battery bank voltage. The panels should be wired in series and parallel -in banks- until they sum up at the desired voltage. You should not exceed 3X the battery bank voltage.

    Fuses must be of the DC variety. They should be 1.4 X the maximum current expected. They should be used between every device -panels-cc-batts-house outlets.

    MC connectors will require you to buy a combiner box- or extra MC cables which are cut to form pig-tails for wiring the panels in series and parallel. You can solder the ends of the pig-tails together to connect positive to positive and negative to negative connections when required. Pre-fabbed MC "Y" cables are available for this purpose too.

    You must ground the system using full 8 foot ground rods and thick copper wire at the panel array and at the battery bank /controller box. You must use 4 or 6 gauge wire less than 5 feet long. You must use a real ground rod clamp. The negative side of the batteries is a good place to run it to...as well as the dis-connect box at the panel array.

    I spent 5 months spelling all this out onto video because all there is out there is partial truths about this serious subject. I have to compete with ridiculous "Build your own solar power systems for less than $200" videos. I think I'm the only real off-grid training course out there. I'm not here to advertise. I want people to know how to do this safely.

    Best of luck!

    Bob Nagy

  7. #7
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    Quote Originally Posted by GreenPowerVideos View Post
    ....... spent 5 months spelling all this out onto video because all there is out there is partial truths about this serious subject. I have to compete with ridiculous "Build your own solar power systems for less than $200" videos. I think I'm the only real off-grid training course out there. I'm not here to advertise. I want people to know how to do this safely.
    Best of luck!
    Bob Nagy -Greenpowervideos.com
    Bob,
    Thanks for your contributions to the forums. BUT - you need to turn your sales pitch off. You can keep the simple link to your site, but since you aren't here to advertise, please limit it.
    Thanks,
    Mike

  8. #8
    Junior Member
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    Hot Springs, AR.
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    Default Thanks for the Guidelines Mike

    Mike- I want to comply fully with the guidelines. As a solar engineer, I do want to
    be able to offer top-quality advice here. I realize too that people mis-use forums to their own advantage. Many of us who have accurate information to share - may be affiliated with solar companies. I guess another moderator removed my Greenpowervideos registration after viewing my original posts. Forgive me for re-registering, but I didn't get a response from my query about that removal and your account does not allow private messages. I will probably only post in this forum area. (my area of expertise)
    If I read you right, I can still sign with my URL, but should refrain from referring to it
    in the body of my posts. That's totally fair.

    So, Am I understanding things correctly?

    Thanks - Bob

  9. #9
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    Default

    pretty much, yep. Generally, a low key link to a sales site is fine, as is a link for a request for parts or whatever.

    Sometimes, someone just posts " Yes, that sounds like a good idea" as a reply to a post and then a 2 page sales link, repeated for 20 other messages on the board.

    But we mods have a tool that just instantly deletes all the spam posts, and bans that spammer, with just a few key clicks.

    Mmike

  10. #10
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    Default solar truths amd myths

    My experience is that there will always be people who cut their nose despite their face.

    Also any discussion on the forum should be clearly marked AS INFORMATION AND SHARED WITH NO LIABILITY TO THE PERSON SHARING IT.

    IT IS NOT ADVISE AS THIS MEANS THAT THE PERSON SHARING THE INFORMATION IS LIABLE FOR THE OUTCOME.

    At the same time sharing information about a complex and potentially difficult topic clearly, accurately, including the physics, engineering and care takne by a professional with the explicit "THIS IS NOT ADVISE" notices illustrates to the enquirer why it needs to be ultimately designed, requisitioned, installed and commissioned by an expert.

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