Power transmission

JoshK
JoshK Solar Expert Posts: 232 ✭✭
If the solar array is not on the house... say 800ft away, how do you transmit the power? I assume you need to step the voltage up high, then back down at the house. What the heck do you buy?

Comments

  • animatt
    animatt Solar Expert Posts: 295 ✭✭✭
    you either buy very heavy wiring. or you can use high voltage MPPT controller. This is for charging batteries. The 2 that come to mind is xantrex and morningstar.
    They run up to about 550v if i remember correctly. You would have to do calculations on which way you want to go. The high voltage MPPT charge controllers are a bit pricey. There is a option of going midnite solar controller the 250v model. This controller is like a middle option.

    This if going grid tied the appropriate gridtie inverter will allow string voltages to go high.

    I sure if you give more details more people will chime in.(like if this is grid tie or off grid{where are batteries in relation to house and panels})

    just to expand a bit. mppt is already designed to operate at somewhat high voltages. and there are several the operate at significantly higher voltages. These take high voltage from panels and either converter to grid power(AC) or converter to battery voltage.(lower voltage dc).

    Running array at 500 volts you would not need much cabling to move power 800ft.
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    JoshK wrote: »
    If the solar array is not on the house... say 800ft away, how do you transmit the power? I assume you need to step the voltage up high, then back down at the house. What the heck do you buy?

    If you're off grid you could have your batteries and inverter by the array and send 120/240 to the house. I've yet to have a system with the batteries and inverter inside. though the farthest was my tiny system with about 100 feet to the camper.
    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.
  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭
    JoshK wrote: »
    If the solar array is not on the house... say 800ft away, how do you transmit the power? I assume you need to step the voltage up high, then back down at the house. What the heck do you buy?

    Like Animatt said, one of those 600 V CC's is the way to go. I am working on an 6KW array at my house that is 1400 feet away. All it takes is 2 paralleled #6 aluminum conductors - super cheap. The xantrex is an 80 amp controller that will do about 2250 watts at 24v and 4500 watts at 48V. The controller does cost about twice as much as a midnite. for 800 feet, depending on your array size, it may be cheaper to run a midnite and buy bigger wire (aluminum is pretty cheap).
  • JoshK
    JoshK Solar Expert Posts: 232 ✭✭
    Animatt, It wouldn't be grid tied. Battery location is whatever is best. So you are saying create the high voltage by putting panels in series, then send the raw DC to the house. I like the idea, can all panels handle this? Maybe it doesn't matter as voltage would be relative to the panel.

    Photowhit, Sending the 120/240 long distances like 800ft would not be possible. I would work fine for a single light bulb, but as soon as a real load turned on the voltage drop over that distance would be massive. And low voltage would damage the appliances.

    I like what Animatt suggested, you have a high voltage and low load making the trip. Would there be a downside to this or another way?
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    I would expect you will need a qualified Lineman to do the work, so that it functions in a safe manner/condition... Also you will need a big transformer or 2, I imagine.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • JoshK
    JoshK Solar Expert Posts: 232 ✭✭
    Ethan, The biggest input I see on NAWS is 250v. Not bad, but I am interested to see a link to one of these 550v CCs.
    Westbranch, I'm nowhere near that point yet, just planning. And besides, I have a wire-cutter... That means I'm qualified, right? LOL
    A set of transformers is exactly what I couldn't put my finger on when I made the post. I am liking the DC idea though. Is there a market for transformers for this tasks, or are we thinking theoretical?
    Thanks guys.
  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭
    JoshK wrote: »
    Animatt, It wouldn't be grid tied. Battery location is whatever is best. So you are saying create the high voltage by putting panels in series, then send the raw DC to the house. I like the idea, can all panels handle this? Maybe it doesn't matter as voltage would be relative to the panel.

    Photowhit, Sending the 120/240 long distances like 800ft would not be possible. I would work fine for a single light bulb, but as soon as a real load turned on the voltage drop over that distance would be massive. And low voltage would damage the appliances.

    I like what Animatt suggested, you have a high voltage and low load making the trip. Would there be a downside to this or another way?

    IT all depends on how much current we are talking about. So how much, or is this just a academic question? Probably running a 600 volt Pv output circuit (probably more like around 400v mpp depending on where you are) and a 600 V CC is the way to go.
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Schneider HV CC:
    http://www.solar-electric.com/invert...wmp80amp6.html

    Morningstar HV CC:
    http://www.solar-electric.com/invert...ontroller.html

    As has been stated, the voltage drop in sending 120/240 VAC would depend upon the load current. Here we feed 240 V AC on 250 feet of # 2 AWG Copper feeders, and the drops are quite reasonable.

    Again, depending on the load current, stepping up the AC at the battery/inverter end, and stepping is back down at the house end is also quite reasonable, unless the power levels are large.

    FWIW, 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.
  • JoshK
    JoshK Solar Expert Posts: 232 ✭✭
    This is academic today. So a 8kwh array could probably take a house off-grid? Let's go with that. So 33 panels if they are 315w each? yikes.

    I have my heart set on these:

    SolarWorld Sunmodule 315 Watt Monocrystalline Panel - $330
    Pmax: 315 Watts
    Voc: 45.6 Volts
    Vmp: 36.5 Volts
    Isc: 9.35 Amps
    Imp: 8.71 Amps

    Weight: 49.6 Pounds
    Dimensions: 78.15" x 38.98" x 1.81"
  • JoshK
    JoshK Solar Expert Posts: 232 ✭✭
    So 13 or 16 panels in a series for a mppt that says 600v?
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Transformers.... there was another poster that had to go ~ 1/2 mile from Array or grid to future cabin, and the consensus was around the transformers he would need. Wire types etc.
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    JoshK wrote: »
    This is academic today. So a 8kwh array could probably take a house off-grid? Let's go with that. So 33 panels if they are 315w each? yikes.
    "

    It really ALL depends upon just what the solar power system needs to do. The 315 or 320 W SW PVs look very nice. Have recently used SW PVs, and think that they are very good, and a great value in a name brand PV.

    For the Scneider 600 V CC, 600 volts is the absolute maximum input voltage, before Warranty Destruct. One needs to use a good String Sizing Tool to get the balance correct for best MPPT voltage range, verses the Voc in coldest weather. It is a balancing act. FWIW, 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.
  • JoshK
    JoshK Solar Expert Posts: 232 ✭✭
    Westbranch, do have a link to that thread or the transformers he decided on?
    Vic, Thanks for mentioning Voc, That's what I was asking in post #11 was Voc vs. Vmp for that determination.
    Thanks to everyone that posted.
  • JoshK
    JoshK Solar Expert Posts: 232 ✭✭
    Yea for Wikipedia... here's info on the War of Currents that was causing me reservations (because I knew DC lost) and the High-Voltage Direct Current article that put my mind at ease!
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Sorry I am having a bad time with searches these days since the "Upgrade"...:grr
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • JoshK
    JoshK Solar Expert Posts: 232 ✭✭
    Thanks.
  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭
    JoshK wrote: »
    Westbranch, do have a link to that thread or the transformers he decided on?
    Vic, Thanks for mentioning Voc, That's what I was asking in post #11 was Voc vs. Vmp for that determination.
    Thanks to everyone that posted.

    If this is an offgrid set up, I dont see transformers being of any use. To use one you would have to invert at the array then bump from 120 or 240 up to 600 then back down, then rectify to get DC again for charging. That is tons of equipment and very inefficient. Just go with the 600 VDC charge controller.

  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Vic wrote: »
    ...
    Again, depending on the load current, stepping up the AC at the battery/inverter end, and stepping is back down at the house end is also quite reasonable, unless the power levels are large.
    FWIW, Vic

    As described, the Inverters AND batteries would be at the head-end, plus the AC step-up. At the home end is the step-down, and distribution as 120/240 AC, IMO. The Inverters for an off-grid system would need to be connected to batteries.

    FWIW, 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.
  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭
    Vic wrote: »

    As described, the Inverters AND batteries would be at the head-end, plus the AC step-up. At the home end is the step-down, and distribution as 120/240 AC, IMO. The Inverters for an off-grid system would need to be connected to batteries.

    FWIW, Vic

    gotcha, I missed that. Im in the northeast so dont really think about the possibility of mounting batteries outside somewhere, but that could work in other places. I think the 600 V CC would be simpler, no more expensive, and more efficient though - in most situations.
  • highvoltpower
    highvoltpower Registered Users Posts: 5 ✭✭

    Simple you have to purchase thick wiring for that or either using high voltage converter it hold off circuit with input range 30–800V and output is 24V.

  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭

    Simple you have to purchase thick wiring for that or either using high voltage converter it hold off circuit with input range 30–800V and output is 24V.

    Or just skip all the bastard hard to find odd pricey components and get a 600V charge controller........