Is 450 feet too far for my panels

mmagmmag Solar Expert Posts: 57 ✭✭✭✭
hello, i am off grid and i am installing ten trina 295w panels to a magnum 4400 watt 48v inverter through a apollo t80hv charge controller, the ideal place to put my panels is 450 feet away from where i am going to put my batteries, i want to run a big enough wire to possibly double my panels if i need to, when i looked at this dc cable sizing tool http://www.solar-wind.co.uk/cable-sizing-DC-cables.html it says in order for me to run that much power i need to be running 120v and i would need 000 copper wire which i around $343 a foot, i am starting to wonder if it is worth it to have my ideal panel location, it says the most efficient way is to run 60v into a 48v system with the apollo, are all charge controllers that way, and am i going to be losing a lot of power running 120v, thanks

Comments

  • offgrid meoffgrid me Solar Expert Posts: 119 ✭✭
    Re: Is 450 feet too far for my panels

    This would be a perfect application for a xantrex 80 600 high voltage charge controller. You could make this run with #8 wire with minimal voltage loss. Well worth the added cost of the CC for the reduction in wire cost.
    Ned
  • BB.BB. Super Moderators, Administrators Posts: 30,629 admin
    Re: Is 450 feet too far for my panels

    Welcome to the forum mmag!

    And, you are finding one of downsides of generating your own power that makes things difficult and expensive.

    The first thing to do is look at your charge controller. The Appollo 80HV should be rated at:
    • Maximum PV input voltage (Voc) … 180VDC Maximum Open Circuit Voltage (Voc), 160VDC Max Operating (Vmp)
    • Minimum PV input voltage (Vmp) ... PV Vmp must be at least 16%greater than the highest battery charge voltage set point. For 12 volt batteries this is typically 18.56VDC, for 24v batteries typically 37.12VDC, and for 48v batteries it is typically 74.24VDC. The input voltage is measured at the inputof the T80 after the wiring and the PV array temperature must be considered with Vmp.

    Depending on how cold it gets in your region (Voc/Vmp rise as the temperatures fall--So you need to size the array so that Voc does not exceed the controller's maximum input voltage on a cold/clear/frosty morning).

    The Vmp rating for your panels (I guess) is 36.6 Volts. And ~120 volts Vmp-array is probably close to the maximum for this controller (Voc-array-cold < 180 VDC).
    • 120 V / 36.6 Vmp = 3.3 panels or 3 panels in series maximum

    That gives you a working voltage of 109.8 volts Vmp-array. Also note that the array will be 3/6/9/12/etc. panels in series/parallel. So 10 panels will not work in this system (2 panels in series is to low of voltage for a 48 volt battery bank, 4 panels in series may hit your maximum Voc-controller voltage limit).

    OK--Now I am a little confused here... Where will the system be located. If you are on coastal California, your low temperatures are probably not much below freezing. If you are in the UK, that could be a lot less. Also, you have other controllers available.

    Besides the suggestion of the Xantrex/Schneider high voltage controller (~400 volts Vmp-array), there are also a couple of Midnite MPPT controller options that can operate with upwards of 200 VDC maximum input Vmp in moderate climates).

    Many MPPT manufactures have sizing tools that can help you with array configurations (here is Midnite's). It appears that you could operate as many as 5 panels in series (moderate climate, 20F minimum temperature) with two parallel strings just fine.

    Raising Vmp-array will dramatically reduce your wire gauge needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mmagmmag Solar Expert Posts: 57 ✭✭✭✭
    Re: Is 450 feet too far for my panels

    thanks for the input, i am located in in inland mendocino county in northern ca, it can be 100 degrees in the summer and there could be a foot of snow for a short period of time in the winter, maybe 20 degrees but its not normal, do you guys know if i will be losing a lot of efficiency running a high voltage? and i should probably get two more panels to make it twelve as bb stated, i got my cc used from a friend but maybe i should look into getting another one
  • BB.BB. Super Moderators, Administrators Posts: 30,629 admin
    Re: Is 450 feet too far for my panels

    My first suggestion would be to pencil out a system with the Midnite controller and see what it looks like. Midnite has great support.

    If that does not work out, look at the Schneider/Xantrex controller. Less support, but should be pretty reliable controller (not cheap, $250 for the firmware implanter tool--or beg/borrow/rent if you need one). Tech support has been mixed (some good, some not so useful experiences).

    Don't worry about running Vmp at higher voltages.. You are probably looking at a couple % of additional controller losses (95% +/- a couple percent). Not a huge deal in the big picture (I do like to keep electronics/battery bank/etc. cool... the will last much longer).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • NorthGuyNorthGuy Solar Expert Posts: 1,925 ✭✭
    Re: Is 450 feet too far for my panels

    I'm thinking about adding a new array myself. Not that far, only 300 ft apart.

    The wire sizing tools are designed to minimuze voltage drop to 3%. Your only load is the MPPT controller, which doesn't need the exact voltage, not to mention that the voltage varies all the time anyway. Therefore, it can live with much higher voltage losses. Therefore, you do not need to be concerned about keeping your voltage within 3%. What you should be concerned is the loss of power in the wires, which you can calculate as I explained in this post.

    You can decrease power loss by using thicker wire, but you also can live with the loss and compensate for the lost power by installing extra panel(s). The second option is likely to be much cheaper.

    The other option, which I decided to follow if I do my new array, is to do as Ned said and use XW MPPT80-600 controller. It costs $1200, but it allows up to 550V VOC, so you can use much smaller wire. Most likely #10 will be enough for you. Saving on the wire, combiner boxes and MC4 cables will be quite substantial, so using this "expensive" controller will save you lots of money.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Is 450 feet too far for my panels
    mmag wrote: »
    the ideal place to put my panels is 450 feet away from where i am going to put my batteries

    Another option is to put your batteries and inverter near the panels and run 240 volt AC to your house. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • VicVic Solar Expert Posts: 2,999 ✭✭✭✭
    Re: Is 450 feet too far for my panels

    Hi mmag,

    MidNite does have two CCs that will operate at higher Vin than the Apollo CC -- The Classic 200, and Classic 250 (as BB Bill noted).

    Classic Brouchere:
    http://www.midnitesolar.com/pdfs/fullPage12Sept10a.pdf

    The Schneider XW 80-600, or whatever it is called could help reduce wire cost, BUT in addition to the generrally poor support from Schneider, in a system where there are no other XW components, this CC MUST have the optional front panel -- the SCP for about $250, plus the noted Implanter if you ever need to update the FW. This doodad is also about $250, although you might be able to borrow one (as Bill also noted).

    Moving Inverter/Batts as vt mentioned could help, although in some installations might make battery maintenance less frequent -- like out of sight, out of mind, etc

    Believe there is a typo referring to the cost of the 000 wire, although bet it feels like $343/Ft when buying about 1,000 feet of it!
    Always many trade-offs. Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 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.
  • mmagmmag Solar Expert Posts: 57 ✭✭✭✭
    Re: Is 450 feet too far for my panels

    Thanks for the help everyone, i think i need to look into getting a higher voltage charge controller and map out what voltage/setup i would like to run, does anyone know of a site that has a chart for wire sizes for different voltages/loads/distances the online calculator is nice but a chart would be handy.
    Another option is to put your batteries and inverter near the panels and run 240 volt AC to your house. --vtMaps
    in order to have the option of pulling 30 amps of power in my house i need 3 awg wire and to run 240 volt ac i would need three wires instead of two but maybe the savings would be worth it.
    Believe there is a typo referring to the cost of the 000 wire, although bet it feels like $343/Ft when buying about 1,000 feet of it!
    oops yeah the price is $3.43 its copper not gold
  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Is 450 feet too far for my panels
    mmag wrote: »
    oops yeah the price is $3.43 its copper not gold
    Gold is a better conductor, though. :D
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Is 450 feet too far for my panels
    ggunn wrote: »
    Gold is a better conductor, though. :D

    I can't seem to find a voltage drop calculator for gold cable. Nor can I find any gold cable with THHN insulation. --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • NorthGuyNorthGuy Solar Expert Posts: 1,925 ✭✭
    Re: Is 450 feet too far for my panels
    vtmaps wrote: »
    Nor can I find any gold cable with THHN insulation.

    Unless it's being smuggled through the customs :)
  • BB.BB. Super Moderators, Administrators Posts: 30,629 admin
    Re: Is 450 feet too far for my panels

    In WWII, the US had a shortage of copper (used in aircraft production) and so the powers that be went to the government's silver reserves and built some silver wire based transformers for use by critical industries.

    Of course, these transformers were well protected by fencing and guards (as I understand), and melted down after the war.

    I remember a National Geographic article from a few decades ago that had a small gold frying pan (great for cooking, author cooked a fried egg in it--very even heat distribution).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • VicVic Solar Expert Posts: 2,999 ✭✭✭✭
    Re: Is 450 feet too far for my panels

    And, War "Nickles" were about 92-ish percent Silver.

    Also, ammo uses Brass and Copper, and a lot of that was used in the war. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 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.
  • solarvicsolarvic Solar Expert Posts: 1,053 ✭✭✭✭
    Re: Is 450 feet too far for my panels

    Here is the voltage drop calculator I use from our host. http://www.windsun.com/Hardware/Voltage_Calc.htm :Dsolarvic:D
  • tallgirltallgirl Solar Expert Posts: 413 ✭✭
    Re: Is 450 feet too far for my panels

    I wouldn't worry all that much about running 240 volt AC over 450 feet. The wires will be larger than the typical #10 for a 30A circuit, but much smaller than the 3/0 you were looking at otherwise. At larger wire sizes and longer wire runs aluminum becomes an option for the service lateral.

    And if the larger wires are a $$$'s issue, Grainger sells 240/480 transformers :)
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,221 ✭✭✭✭✭
    Re: Is 450 feet too far for my panels

    It does not matter if it is worth the cost of locating an off grid array in the perfect location. You have to do this! The XW-80 will be the easiest way. You will need a system control panel and some number 10 wire. Good Luck!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • toothytoothy Registered Users Posts: 23 ✭✭✭
    Re: Is 450 feet too far for my panels

    I have an XW-80 600 volt controller and scp. It works great, we however are just incompatible.

    I have a little less than a 250' run but used it for a different reason, I have the exact space for 13 panels and 13 doesn't work well in string calculators, so series it was. I found some extra space for 3 more panels and now am looking to get rid of the Xantrex and replace it with a Classic 200 so all 3 of my Classic kids play nice together.

    I'm with Mr Sparks, location, location, location!

    Wade
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Is 450 feet too far for my panels

    be aware that higher input to output ratios on voltage can be a pain too as this manifests into higher controller efficiency losses and it can be a wash. use the thickest wire you can afford as there isn't any real substitute. you may still need a higher voltage as the costs of wire are very high as you pointed out. they aren't over $300 a foot though. running it at 240vac may be an option to help overcome losses.

    also even though many times the current and thus the power of the pv output will be less there are plenty of times it is at rating and sometimes even more. you should design it for as low as you can in v drop loss % and the higher voltages do help in that area greatly for as if one would have say for example 5v in v drop losses on a long run for 48v this is almost a 10.5% v drop loss and is not acceptable. now that same wire and voltage drop with a 120v system would translate to 5v/120v=4.167% or much closer and may be more livable as some point out. it is still too lossy, but if you may be able to live with it at this level it will still work. we make recommendations of 2% with no more than about 3% as a good rough guide, but sometimes this is too difficult to obtain.

    northguy,
    you will find that i had done the calculations for everybody on here by hand years ago much the way you indicated in another thread until somebody put the formulas and data into a spreadsheet and is the basic voltage drop calculator you will see in my sigline. i had no control of how he laid it out and only gave some general advice as to layouts. my pc skills are non-existent when it comes to spreadsheets. if you have good pc skills and would like to lay it out better i could give you the unlock code to delve into it providing it stays as freeware.
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