Building a panel with cells

shdi_us
shdi_us Registered Users Posts: 11
I have about 120 3x6 evergreens and looking into making a panel. My biggest questions are about wire gauges and diodes. I understand diodes are required to prevent the panels discharged after dark/shading. Whats makes the most efficient use of them, one per 36? or can i use one after a set of 3? one in the combiner box? or do some charge controller or inverters not require diodes? I found information for the wire gauge after the combiner box, but no specifics about the wires going into it. Also, does this site have a FAQ i can refer to? Thanks

Comments

  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    I just read a reply in another question

    A diode is not needed with a charge controller.

    where diodes used in the past and the information about them just comes up from time to time? Or are they simply used in small systems like a battery and a flashlight?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Building a panel with cells

    For smaller panels used with larger batteries, and very simple/cheap systems, the blocking diode is/was a cheap and dirty way to prevent the panel from discharging the battery at night.

    Smaller wattage panels (typically under 100 watts), many times, still have the blocking diodes. Larger panels (typically over 100 watts) will not have the blocking diode.

    There is also another type of diode--the bypass diode. This allows a several panels in series to continue to supply power to a charge controller or Grid Tied type inverter (typically MPPT type) where one panel in a series string has shade and the others are in sun--allows the current to "go around" the shaded panel.

    In real life, shading really cuts performance of a solar panel system--full sun/no shade is really required for proper operation.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building a panel with cells

    as to your other concerns we have to be sure that we are all on the same page here. each evergreen is roughly a 3ft by 6ft panel in and of itself. multiple panels will make an array. it will be helpful if we know what you are trying to do with them. would it be a gt system with or without batteries or an off grid system and at what battery voltage.
    now if that 3x6 refers to inches for each cell then they aren't evergreens as i don't know of them selling individual cells of their string technology.
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    Thank you very much for the diode information

    here is the link to my cells

    sorry i had to edit this out as ebay links are not allowed. niel

    They are 2 sellers on ebay with them, and both claim to be evergreens.

    My final intention is still unclear, i have little funds and trying to save every cent, but i would love to have a battery less gridtie system. Im reading and having batteries increases efficiency even on grid tie systems due to varying voltages? I'm open to a battery offgrid too, but I'm doing this piece by piece and i think that would be difficult to impliment. Im in Indiana, and my electric company(Duke Energy) offers solar panel support beyond what is required by state. Thank You

    Edit: I believe i wish to start with 5kwatt system, but using calculators based on my state i need about a 7200 system to power my house, was planning on building a 10k watt eventually.
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    Just watched Roderick Young DIY Video. And that answered a ton of my questions.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Building a panel with cells

    Is this the movie you watched?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    yes, watched every bit of it, i had no idea that the pv system went into the ac system with a breaker. Im going to complete one of my panels, and then see about a mounting system. I have an aluminum foundry next to the house that can make anything i can draw up, so i think i going to soon be commissioning some work.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building a panel with cells

    you might want to locate a glass factory too, but one that'll make it low iron, or was that lead, and impact resistant.
  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    Re: Building a panel with cells

    We seem to be getting a lot of these DIY solar panel posts lately, and every one seems to be an indication that it is not worth the effort.

    http://forum.solar-electric.com/showthread.php?t=4833
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building a panel with cells

    we tell them, but they keep coming and don't always seem to want to listen. maybe the bots are finding this diy stuff posted here and making it a target for other searches?
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    hmm.. im not sure i think i found this website when searching inverters, and about the glass, i do have a glass place in the next town.

    I did read the entire fire panel thread, and those were defiantly DIY panels, the contractor, if there was ever a contractor, made them and in poor fashion.

    no worries, this is my plan so far

    aluminum frame, with plastic insert that the panels get placed on, then a clear top,

    there is nothing wrong with a diy, just that you cant cut corners or you pay the price for it,

    A diy WILL NOT be the most efficient, there will be spacing requirements from the smaller cells being used.

    Most DIY cells are broken factory cells, that have been laser cut to smaller sizes.

    Edit: The weight in solar panels is not from the cells, and is from the frame itself, so if your DIY doesnt weigh anything, your doing something wrong, Ive seen them on cardboard(whos bright idea was that?) OSB/Plywood.

    If you look at the fire panel thread, and see its supports, there is very little chance that junk would support a real panel.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Building a panel with cells

    As you can see--we usually give the warning that building your own panels is not cheap (typically around $1.00 per watt for the raw cells), and they will probably not last more than a few months or a year or so (at most) before failing.

    And, building high wattage/high current panels on plastic substrates would never meet NRTL listing (fire hazard). And home made panels (with plastic/wood components) should never be mounted over a flammable surface or on an occupied structure.

    You can buy large panels (blems, over-runs, etc.) with full 20-25 year warranties for $3-$4 per watt -- or if you are lucky, look around, down to $2.50 per watt for 200 watt panels on occasion (before taxes, insurance, and shipping charges).

    At this point, with the financial fall-out, plus massive increase in solar panel production--the entire industry appears to be in an over-supply condition right now. Pushing prices lower--and probably not a good time to open a new panel assembly company.

    If people want to build their own solar panels--typically, some sort of thermal (water, antifreeze, air) type panel lend themselves very nicely to home-built DYI projects. Thermal panels are more efficient and much smaller than similar energy collection from solar PV electric panels. And if you save $40 in electricity or $40 in natural gas/propane/oil costs--the savings are still the same, which much lower capital costs for solar thermal systems.

    But, for people that still want to try and build their own--we still attempt to help the best we can.

    Just the kind of folks we are. ;)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    Ive done some searches for a $2.50 and dont seem to be able to find any.

    What i would like to do is find some for $2.50 that are out of state, avoiding taxes if done over the internet, but still close enough that i could take the truck and trailer over and pick them up.

    That being said im going to start by playing with these 3x6s, but i welcome any links to $2.50 watt panels.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building a panel with cells

    shdi us,
    i don't know if you want to pick them up yourself from florida or not.
    http://www.sunelec.com/

    it seems that this isn't the only place getting hit with diy requests on pvs.
    this is on sunelec,

    The Do It Yourself Solar Panel Scam
    Building your own solar module can be fun and exciting. However if you want to power your building on solar power it is best to purchase manufactured panels. The cost of the materials, time, and labor will cost you more than if you buy a panel that is already guaranteed to produce over 40 years of use with a 25 year warranty. With a manufactured panel you know exactly what you'll get and you will know that the panel is functioning correctly. In the end you'll pay more and get less power and life
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    hmm.. not a terrible deal at all there, Florida a bit far, there's a plant in ohio, but they ship everything out to Germany, Thank you very much for your link, and it now on the top of my list.
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    well, i guess plastic lining is out of the question then? high voltages? I guess the question i have then is when making an array, are you doing it series or parallel when building a grid tie system.

    Edit: I really like this inverter XW 6048, what you think?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Building a panel with cells

    Panels do have a plastic like backing--just not a lexan/plexi panel (which has more material to burn).

    The XW product line is probably the best designs out there right now (charge controller, inverters).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    k, thanks for the reply, I wasn't planning on using acrylic for the backing, i understand the comments now.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building a panel with cells

    "I guess the question i have then is when making an array, are you doing it series or parallel when building a grid tie system."

    assuming a 48v battery bank, you will want your array around the 72v point for 3 seriesed 24v pvs or about 60v for 5 12v pvs in series. you could go a bit higher, but i'm considering better efficiencies for you staying on the lower side of things. if you need more current then you parallel identical series strings until you reach the target current desired, limited by the controllers you employ. so the proper answer to your question is series/parallel as you will use both.
  • shdi_us
    shdi_us Registered Users Posts: 11
    Re: Building a panel with cells

    After much research, I found the correct backing for solar cells

    http://livingoffthegrid.ecrater.com/product.php?pid=723285

    this is just the first site i found explaining it, still experimenting with my cells, maybe in a few weeks ill have a full panel i can post a pic of.