looking for advice on a solar and wind setup

[max farley]

I'm looking for some advice on getting a setup built for my of grid home. I've got 12 panels 6 of which are 235W 30V 7.9A, and 6 of which are 255W 30.5V 8.4A. I also have a 350W 24V turbine as well as 12 2V batteries.

So I'm wondering what's the best way to wire the panels, does the turbine need to have a separate controller or are there combination controllers, does the wind turbine have to have a dump load, what wire gauge would I need to be most cost affective.

 

[Hedges]

Don't

 

[Hedges]

But if you do, don't expect much from wind. Usually not effective from what we hear.

Wind turbine must go through a charge controller. No-load, its output voltage likely goes to high for the charge controller, so a "clipper" is needed. It can also over-speed, so dump load, shunt regulator, etc. is needed. Does it have any other braking for furling mechanism?

Look up Midnight Classic with clipper, to see an approach.

350W 24V is 15A, so probably 14 awg or 12 awg is suitable.

 

[MichaelK]

For the panels, I'd go with 3S, keeping strings of panels with one brand only. As a general rule of thumb when you wire panels in series, the maximal amperage that can flow through the wire is limited to the amperage of the lowest individual panel. So, if you mixed together a string with both 8.4A panels and 7.9A panels, your maximal output could never exceed 7.9A.

So, wire two parallel strings of the 235W panels, and an additional two strings of the 255W panels. Wired 3S, the first two strings will be 90.0V and the second two strings will be 91.5V. That's <5% difference, so your controller will never notice the difference. With four parallel strings, you are required by code to have each string fused/breakered. A combiner box works nicely here. I have the Midnight six breaker box. You'll want to have a 12A breaker for each string. When combined, the total output of the combiner will be ~ 32.6A at ~ 90.7V, more or less.

If you went with the Midnight250 as your controller, you might be able to wire all six panels into one series string, but use this string calculator, and your all-time winter lows with Midnight's string calculator to make sure your max Voc doesn't exceed the controller's limits.

MidNite Solar - Classic Sizing Tool.

MidNite Solar is the industry leader and manufacture of quality Renewable Energy System electrical components and E-Panels.

www.midnitesolar.com

I agree with Hedges. Wind is likely to be disappointing. Unless you have to have your hat tied to your head when outside, you likely do not have enough wind to make it worthwhile.

BTW, what is the Ah capacity of your batteries? This will be a 24V battery bank? With the two (or 4) strings of panels, the max current they are likely to make is (235W X 6panels) + (255W X 6panels)/25V charging = 117.6A. Even with 85% derating, that's ~100A. That amount of current is about right for a 1000Ah battery, but one single charge controller is not going to handle that much current. The Midnight250 can only handle a max of 62A charging a 24V battery, and the Midnight200 70A. You might get by with a single Midnight150 which has a 94A limit at 24V, but that's pushing it right to it's limits.

 

[Hedges]

So SCC will clip when production is high, deliver full power without clipping off-season or with sun partially obscured. Probably fine.

PV strings of multiple orientations, can reduce peak to as little as 70% as high so no clipping. Extends hours of production, keeps battery full later in the evening so few Ah discharged at night.

 

[max farley]

thank you for the advice. the main reason I am hoping to use wind along side the solar is that the area is prone to thick fog and decently high winds. Also unfortunately i don't know the Ah of the batteries, all i really know is that they are 2v and came from a forklift.

 

[Bluedog225]

Small scale wind only brings sadness.

 

[OzSolar]

thank you for the advice. the main reason I am hoping to use wind along side the solar is that the area is prone to thick fog and decently high winds. Also unfortunately i don't know the Ah of the batteries, all i really know is that they are 2v and came from a forklift.

But do you always have decently high winds every time there's thick fog?

Define decently high winds and at what height? Off grid, right?

As has been mentioned you will likely be disappointed. You can put a lot of fuel in a petrol generator for the cost of a turbine, it's tower and the wire to your power center. A turbine that will likely fail long before it would have offset that fuel cost and then you're back to where you started.

If you've got the money to spare and think it would be fun then by all means go for it and report back often please!

What turbine do you have?

 

[max farley]

its a 350w 24v from superwind, i think. and most the time the wind is decently strong when the fog rolls. I've recorded speeds of about 20m/s stood on the front steps and i know its been higher but that's not normal but some where between 8-12 is fairly regular

 

[C&K]

I'm looking for some advice on getting a setup built for my of grid home. I've got 12 panels 6 of which are 235W 30V 7.9A, and 6 of which are 255W 30.5V 8.4A. I also have a 350W 24V turbine as well as 12 2V batteries.

So I'm wondering what's the best way to wire the panels, does the turbine need to have a separate controller or are there combination controllers, does the wind turbine have to have a dump load, what wire gauge would I need to be most cost affective.

As others have said, the wind turbine won't be that useful. We had an 11ft diameter turbine here on a 90 ft tower with a Midnite Classic controller on it. It could produce up to 2,800 watts. But total energy production is the important thing. Most days it only produced less than 1kWh.

So based on experience, a single 50W solar panel will produce more energy day in and day out than your 350 watt wind turbine ever will. A wind turbine has to be in clean air above any turbulence, and what you "feel" standing on your front step is due to ground turbulence, not the clean non-turbulent air a wind turbine requires.

In the end we got a crane in here and dismantled the wind turbine, took it all down and sold the Rohn tower. The thing was noisy, unreliable power output, and climbing the tower once a year to grease it and maintain it was a pain.

 

[OzSolar]

I've recorded speeds of about 20m/s stood on the front steps and i know its been higher but that's not normal but some where between 8-12 is fairly regular

While that sounds impressive it may not mean much. Can you find a detailed map that also states the height above ground like this and zoom in on your exact location? Just guessing but it looks like 95% of England's coastline is 15 knots or much less annual average wind speed.

350w 24v from superwind

As @C&K pointed out energy is all that matters. Here's their published power curve which is likely quite optimistic. If they have an energy curve I can't find it which is a red flag. A reputable manufacturer at least tries to publish an energy curve and even then you have to discount it by at least 50% for doing feasibility calculations.

 

[OzSolar]

As others have said, the wind turbine won't be that useful. We had an 11ft diameter turbine here on a 90 ft tower with a Midnite Classic controller on it. It could produce up to 2,800 watts. But total energy production is the important thing. Most days it only produced less than 1kWh.

So based on experience, a single 50W solar panel will produce more energy day in and day out than your 350 watt wind turbine ever will. A wind turbine has to be in clean air above any turbulence, and what you "feel" standing on your front step is due to ground turbulence, not the clean non-turbulent air a wind turbine requires.

In the end we got a crane in here and dismantled the wind turbine, took it all down and sold the Rohn tower. The thing was noisy, unreliable power output, and climbing the tower once a year to grease it and maintain it was a pain.

Thank you for sharing your story. This is how 99% of small wind stories end and hopefully you will help someone else from making an uninformed choice.

I've been around nearly every brand and size of turbine. Most of them were total garbage, even the best ones were total failures by any metric you would choose. Even or perhaps especially the insanely expensive Bergey.

I'm pretty sure most wind turbines never even pay for the wire between the turbine and the power center. They certainly never pay for themselves or the tower.

If only more people shared thier stories....

What turbine did you have?

 

[C&K]

Thank you for sharing your story. This is how 99% of small wind stories end and hopefully you will help someone else from making an uninformed choice.

I've been around most of them. Most of them were total garbage, even the best ones were total failures by any metric you would choose. In fact I'm pretty sure most wind turbines never even pay for the wire between the turbine and the power center. They certainly never pay for themselves or the tower.

If only more people shared thier stories....

What turbine did you have?

We had a Bergey XL that had been modified to use the Classic controller on 48V. It was on a 90ft Rohn free-standing tower. When we took it down we sold the tower for $11,300. We couldn't give the wind turbine away, nobody wanted it. So it eventually got scrapped. I kept the Classic controller and still have that but haven't used it for over a year.

 

[OzSolar]

We had a Bergey XL that had been modified to use the Classic controller on 48V. It was on a 90ft Rohn free-standing tower. When we took it down we sold the tower for $11,300. We couldn't give the wind turbine away, nobody wanted it. So it eventually got scrapped. I kept the Classic controller and still have that but haven't used it for over a year.

That turbine had a rotor diameter of just over 8'.

 

[C&K]

That turbine had a rotor diameter of just over 8'.

No, you are thinking of the XL1 which is a 24V machine. This one was a XL10 and was originally a 10KW grid-tie turbine. They put a smaller 11.5 ft diameter rotor on it to make it run faster to lower the cut-in windspeed to 5mph, and rewired the stator in it from wye to delta so it would output 90VAC three-phase/130VDC. It was done by the doctor that built this place before we bought it.

But it was never high enough. It needed a 120ft tower because at 90 ft it was only about 20ft above the top of the pine trees. The only wind direction where it would work decently is with the wind from the north-northwest where the wind had a direct shot across the lake into the turbine rotor. A couple times when we would get wintertime winds from that direction it would run at 1,500-1,800 watts continuous with peaks up to 2,800 watts. But the rest of the time it did basically nothing because of turbulent wind off the treetops.

And this is the problem with wind turbines; they require laminar flow wind to work. People stand in their yard and say, boy the wind is really blowing. Or they watch the treetops moving in the wind and think they got a lot of wind. But what you're seeing is wind compression from ground friction, which can actually increase the velocity of the wind blowing around buildings or trees on the ground. But it's not laminar flow and your wind turbine rotor is not efficient because it's doing the equivalent of cavitating all the time.

So my wife hated the thing. It was noisy because it ran at very high speed. At cut-in voltage to about 9-10 mph wind speed it made a "groaning" sound that resonated in the whole tower. It was unsightly. I hated climbing the tower to grease the turntable on it. It was an insurance liability because the insurance company wanted us to put a fence around the base of the tower to keep people and kids away from it. And once you have one they are just about impossible to get rid of. It cost us $2,100 for a crane to take it down - the machine weighs about 1,000 lbs. We managed to sell the Rohn SSV tower for $11,300 but I had to take that apart myself after the crane laid it down. And after we took it down we never never noticed bit of difference in how much our diesel generators run in the wintertime.

 

[Hedges]

Tilt-up tower could avoid needing crane. Pretty hefty to tilt 1000 lbs. up 100', though. I figure 5000 lbs. if using a 20' strut at 90 degrees to the tower.

The generator and electronics ought to be good for hydro, for someone with enough flow and head. Or PTO for someone with a tractor? (what RPM did the Bergey operate at?)

 

[Bluedog225]

So much sadness…?

 

[C&K]

Tilt-up tower could avoid needing crane. Pretty hefty to tilt 1000 lbs. up 100', though. I figure 5000 lbs. if using a 20' strut at 90 degrees to the tower.

The generator and electronics ought to be good for hydro, for someone with enough flow and head. Or PTO for someone with a tractor? (what RPM did the Bergey operate at?)

Not with a Rohn SSV. It is a tapered tower. I'd have to go out and measure across the anchor bolts in the concrete footing but I think it was about 7 feet across at the base. That tower weighs about 8,000 lbs. Sold it on an online auction for $11,300 broken down in 20ft sections.

I don't remember the voltage specs on the generator head, but I think it was wound for someplace between 400-500 rpm to reach 130VDC. It was put up in 2013, so it was there for 9 years before we took it down. Didn't get a single bid on the turbine, ended up hauling that to the scrap yard. We were glad to see it gone. It ran up there for many days and since it was always turning people thought we really had it made. Only problem was, it was either running below cut-in speed or only making about 80 watts at 8mph wind speed, with occasional peak up to 150 watts in a 10mph gust. The wind had to blow at least 15 mph to get 500 watts out of it, and 20 mph to get 1,000 watts. 30 mph it would do 2,200 watts.

We just don't get those kinds of wind speeds here. Average day is about 8 mph. The doctor that built it and put it up before we bought the place had more money than sense.

 

[C&K]

What we were told, by the doctor's son that sold us the place, the wind turbine was put up originally with the 23 foot rotor on it. I think they are derated to 6500 watts for a battery charging application. But it never made any power at all because the cut-in wind speed was too high. So they took it down with a crane and modified it. He had to have had at least $100,000 in that turbine which I think is ridiculous.

 

[OzSolar]

What we were told, by the doctor's son that sold us the place, the wind turbine was put up originally with the 23 foot rotor on it. I think they are derated to 6500 watts for a battery charging application. But it never made any power at all because the cut-in wind speed was too high. So they took it down with a crane and modified it. He had to have had at least $100,000 in that turbine which I think is ridiculous.

That's sounds like someone went way off on a tangent in an attempt to salvage a project that never stood chance. AKAIK, Bergey never produced such a turbine. Maybe they reluctantly helped with a one-off science experiment but it was never something you could order from their standard offerings.

I've been called in to clean up several similar messed up situations. Sometimes it's by the utility company, other times it's by the heirs needing to clean up Dad's place so they can get it sold. Eerily similar story to yours.