Windmill wire run.

[Bigbear]

I have an AirX right next to the house that is not of much use due to tall trees.  I have the AirX up about 50 feet, but it still gets into wind gusts and quickly turns another direction and stops.  I have an open area that would get the best wind, but the distance is about 230 feet away.  Can I run an overhead Alu. triplex from the wind generator to the batteries?  If you think this is possible, what size would it take?  The AirX is 12 volt, and I think it is suppose to put out about 600 watts in really good wind.  As the days grow more cloudy, I really need the input from the AirX, solar panels are keeping up, but not by much.  Please help, and thanks, BEAR

[Flux]

230 ft is a bit of a tall order at 600W without serious cost in cables.

When you accept about 200W from the AirX then the cable is less of an issue but it's internal regulator will probably cause you grief.

Aluminium cable is a real pain but if you can get it cheap and use lots of it in parallel it will be ok.

Try to keep the total cable resistance below .1 ohm, lower is better.

Flux

[Bigbear]

Thanks for the quick reply Flux, what do you mean the internal regulator will cause grief.  I have noticed when the wind is blowing pretty good, the blades do not turn, or only a few revs.  Could the AirX be shutting itself down, due to the fact the batteries are already full?  I have the AirX hooked up to the batteries seperate from the solar panels, via large copper buss bars that all neg. and pos. cables hook to.  The AirX said it should be hooked to the batteries, so it can check the charge level, maybe it would run if the batteries became low and no other charge means were available.

I can get the alum. cable pretty cheap, what size wire should I run for that 230 feet?

[Flux]

I am not entirely sure how the Air X regulator works. If it checks the voltage on open circuit then it should be ok. If it doesn't go completely open circuit then any excessive volt drop in the cable may trick it into thinking the battery is fully charged. You have to be very brave to let a windmill off load, I wonder if they compromise.

If you find it braked most of the time it probably thinks the batteries are full. You may need to set the regulator volts higher, you should be able to keep it working up to equalising volts, it's not going to hurt at that for the little it will produce.

In high winds it will brake frequently to keep its speed down. It should still keep coming on and off until the regulator tells it to shut down on high volts, then it will stay braked until the volts drop.

Not sure how they can claim 600W from something that runs in fits and starts with a possible peak output of 600W.

Sorry I have no idea of the cables you have available, we work in sq mm not in your AWG sizes.

Flux

[SamoaPower]

I would suggest #2 copper or #1/0 aluminum, but I wouldn't use aluminum personally.

The AirX is only rated at 400 Watts at 12.5 m/s or 28 mph.

[Slingshot]

I'm not sure about the AIRX, but the previous incarnations of AIR (of which I've owned two) pulsed-charged and sampled voltage between pulses, making the wire resistance pretty much irrelevant.

The main problems with AIR regulators were:

1.  They're in the unit, which puts the adjustment screw on top of the tower.
   
2.  They had no reverse-polarity tolerance or protection.  A fraction of a second touching the output wires to the wrong battery terminal resulted in a damaged unit.  You could fix this by building your own circuit with a fuse (and shunting diode to trip it), but it was almost unconscionable to ship such frajile units to unsophisticated end users.
   
   

Apparently (1) is still an issue.  Don't know the current status of (2).

[altosack]

BEAR,

Without knowing what your peak energy wind speed is (I can't believe SamoaPower didn't mention this !), it's hard to recommend a wire size. In general, size it so you have little loss where you get most of your energy, and don't worry about the high wind conditions. Not only are they probably rare, but your batteries will tend to be fuller at these times, and a little more loss won't hurt.

I'm going to assume that most of your energy comes in at or below 10A (about 130-140W, probably about a 20 mph wind speed with the Air-X). Since it's 12V, I would probably allow 5% loss at that rate, so about 0.6V loss, or 0.6/10A = 0.06 ohms.

With 230' x 2, this gives 0.12 milliohms/ft, or 1 AWG copper or 1/0 aluminum (this is from memory and calculated in my head, so you should check it). I agree with SamoaPower, I would stay away from Aluminum unless you know exactly what you are doing and how to install it to not have corrosion problems.

460' of 2 AWG copper conductor (1 AWG is not common, and 2 AWG will increase your loss at 10A to 6-7%) is pretty expensive; have you thought about a taller tower ?  If you're just moving 230', if you have turbulence problems now, they probably won't go away, even if they are diminished somewhat (unless your move is vertical as well as horizontal).

Dave

[wpowokal]

Bigbear, just an early morning thought but if the best site is 250' (83m) which I personally would not have a problem with, 12v is a problem though. Could you invert the power to AC or use a 12-24v converter at tower base and step it down at the other end.

Any chance of some site pictures? My duel rotor has some problems with trees for certain wind directions, not my usual winds though. It's about 30 trees and I will remove them when I am happy that what I have planted more than replace them.

I too would stay away from aly cables for the reasons mentioned. I have no understanding of Air X, but it does occure to me that there are more options to be explored here.

allan down under

[stephent]

wire loss (voltage drop) is easy

voltage drop= 2 x (one way line length) x amps x wire resistance (R factor in books)

              ---------------------------------------------------------------------

divided by       1000

or 2 x (one way line length) x I (amps) x R factor / 1000

your case and #1/0 aluminum is

supposing 400 watts or so peak (more.less 30 amps @ 13.8volts)

so   2 x 230 (ft) x 30 (amps) x .201 (R for 1/0 aluminum) / 1000= 2.77 volts drop

and  2.77 (volts drop on line)/ 13.8 (volts nominal) = 20% line voltage drop more/less.

Too much really to see any gain from what you have now.

Keep the line voltage drop to 5% or so for ballpark figures (usually very hard/expensive to do with 12 volt system and long line lengths).

Using #2 copper is the exact same voltage drop.

That much distance is going to eat your lunch in conductor size/costs.

[jlt]

Why dont you put a battery shed at the bottom of the tower. and use a small 200watt inverter on it .  I have one airx that i played with . it made more noise than it made in power. i took it down to avoid problems with my neibors that were 400yds away.

[tecker]

 Down the tower and into you battery location your talking 300 + feet you can get 10 at home depot for $60 per 50 ' four rolls should do and , the conduit run will be the labor intensive part . 4 awg 10 at 300 feet you would loose around 1.5volts so what I 've done is to use a 2x 2 pvc box every 100 ft in there I have 2 7ah batts parallel this eliminats the voltage drop when the batts stay plumped up . You can also use 2 farad car audio caps the 7 ah has simular characteristics .

[tecker]

 sorry that's $60 for 500'

[Bigbear]

Dave, I checked the AirX and it's rated at 400 watts in a 28 mph wind.  Going higher is possible, but it seemed like it would be easier to move the AirX.  The spot I want to move it to is on my south property line, which is an open field for a mile or so, no trees to the south, south east, or south west.  Most of our wind comes out of the south west, so it would be wide open to most all wind.  A friend of mine is an electriction, and I can get left over triplex alu. very cheap, I do realize that you have to use oxidation paste, etc at any connections.  Spliceing them together is no problem, he has all the water tight fittings.  Tonight I will try and get a down to the exact foot count of wire I will need.

I really appreciate all the input from everyone, you guys are life savers.

Someone mentioned using an inverter at the AirX, with battery I would assume, but, what would you do when it gets back to the battery room?, convert back to 12 volts?  It might not get wind for several days, and the batteries would run down at the AirX and I would have to charge them in place somehow.  BEAR

[altosack]

400W @ 28 mph is your peak POWER wind speed (not site dependent), not your peak ENERGY wind speed, and you don't need to size your line for this, for the reasons I gave in my previous post.

If you don't know what I'm talking about, I mean at which wind speed do you get the most energy, that is, power X time. If you get 50W @ 17 mph for 40 hours/month, and 400W @ 28 mph for 1.5 hours per month, the 17 mph winds do you a lot more good, since they give you 2000 W-h, whereas the 28 mph winds only give you 600 W-h (in reality, it is probably even more skewed towards the lower wind speeds).

If you don't have a wind energy profile for your location, Flux, SamoaPower, and I are all recommending about the same thing (I didn't notice this when I first posted), and it will do well enough for you if you can get the wire cheap. And, if the cost of the wire is not a problem, I would definitely keep things simple and not try the other schemes mentioned (such as the inverter at the AIR-X).

All the best,

Dave

[thefinis]

Don't know if this will get seen or help but here are some tables that should give some loss figures based on wire size and distance.

This top one has a program at the bottom of the page for figuring voltage drop in al or copper wire. It is a good place to start but you need to read most of the warnings and suggestions.

http://www.powerstream.com/Wire_Size.htm

http://www.windsun.com/Hardware/Wire_Table.htm

This is a chart for DC Flux or anyone who needs it the last one has a metric to awg size chart

Finis

[tecker]

 Just a note .I Know your locked in to the three conductor Aluminum . Probably for  the price . There's a few hazards running a wire run overhead . You have probably thouht of most hazard versus price ,Price wins almost every time .My take on overhead wire is It's a lightening magnet .Protect both ends. Sooner or later you'll get a shot . If you have an unused conductor you may be able drive a rod on both ends and lift that ground bond up to the ariel run . You'll be at peak power during bad weather not wanting to shut the genset down so surge and breaker both ends . Every long run of wire I have around here has gotten a strike the lower the voltage the more likely to get hit .My under ground runs have the least numger of hits.

[kenputer]

 When the air-x regulator checks the battery voltage it shuts itself down , it does not freewheel. You should also connect solar panels at different points on the battery bank other wise the air-x regulator might read the voltage from the panels and shut down and go into stall. One other thing is the led on the air-x will flash 10 times a second if the battery is full and shut down.

Ken