Jeff,

Thanks

Bill Wilson

Bill,

I saw an ad for a car that can go 120 miles per hour, but that does not mean I can drive it down the Interstate at that speed if I buy it. In other words, the ad you reference may say you can turn your meter backwards, but you cannot do it legally unless you install all of the required safety dis-connects as required by your local utility, you complete their application form, and then they replace your existing electric meter with a model that records each in and out electric flow separately. Some states have other requirements like providing the utility with a copy of your homeowners liability insurance policy and having a lockable handle exterior disconnect switch for their use.

Although this company is known for their quality wind products, I don’t like having the inverter mounted 75 feet up a pole and subject to all the weather extremes. The inverter is the weak link in most of these systems and I want a system where this is at ground level and have as few electronic components as possible up on a tall tower and in the weather.

Most small wind systems generate DC power for battery charging. What they have done is mounted a DC to AC inverter inside the wind turbine to convert the DC electricity from the turbine into 120/240 VAC which can feed back into the utility grid. However, you cannot legally just plug this into the wall outlet and “turn your meter backwards”.

On another note, for those readers wanting to do something like this, please understand that the power output from any wind turbine is “wild”, in that it jumps constantly all over the place as the wind changes direction and flow rate. You cannot use a standard DC to AC inverter with a wind turbine since the voltage and current goes to such extremes every few seconds. Most inverter manufacturers make a “modified” version of their solar inverters to work with wind turbines, and most are designed for ground mounting in a protected area.

Also note that there are very few areas of the US with enough wind to make these worth the cost and the easiest way to tell is if there are already other wind turbines nearby. Those areas of the US with lots of wind year-round are usually already covered with wind turbines. Although you might be the first in your area, you may want to check a wind resource map for your state first before paying out $6000 plus.

Good Luck,

Jeff Yago

Share this entry

Jeff,

Charlie and Sara

Charlie and Sara,

If you guys want to “play around” with this proposed system as a learning experience then go for it but remember, a 20 amp circuit could easily kill you under the right grounding conditions. However, I can offer you some warnings if you ignore that advice.

If you check a recent email question from another person wanting to do this same thing, I pointed out that most wind turbines cannot be connected directly to a standard solar inverter because the output power is “wild.” A grid-connected wind turbine requires a special, modified solar inverter designed specifically for a wind turbine, and if you go the way you are going I am willing to bet you will quickly burn up your inverter which is NOT designed for this type application.

You also cannot connect a solar module and a wind turbine together to “jump start” the system as you describe. Each will require their own charge controller type device to prevent reverse charge flow and coil damage.

If you want to know wind potential at a site, you can purchase a recording wind meter for $74.00.

I don’t see how your approach will teach you anything useful except how fast you can fry electrical equipment, as a real wind turbine installation will not have the same performance issues of your experiment.

Also, you have not describing any safety disconnects, fuses or circuit breakers, and have not discussed the fact that it’s against utility regulations to make this connection to the grid without written approval, and this requires evidence that your inverter is both UL listed, and certified for grid backfeed applications.

Again, I am not against experimenting as a learning process, but I am afraid all you will discover with this approach is how fast you can burn up several hundred dollars worth of equipment.

Be very careful,

Jeff Yago

Share this entry

Jeff,

Thanks for offering this service.

Mark

Mark,

I think its great that you want to tackle a project like building a wind turbine. If you are going to use it to charge a set of batteries for a backup power system then that would be the way to go, but you will not be able to connect it to the grid.

Just a small point, a “converter” is used to convert AC to DC, and “inverter” is used to invert DC to AC.

First, the voltage and current output from a wind turbine is all over the chart as the wind keeps changing by the minute, which requires a very special DC to AC inverter designed for this type power input, plus be certified to feed power back into the grid. The lowest cost inverter I have seen that is designed for this type application and certified for grid connection costs around $2,500.00, plus circuit breakers and wiring. Your local utility will not allow you to feed power back into the grid unless the inverter has these UL and IEEE certifications, and you will not find this level of quality in any $300 inverter..

Sounds like you are on a tight budget, so I would stick with charging batteries and powering some emergency DC lights.

I will point out that many who ask me these type questions totally ignore my advice and go on and waste a lot of their time and money to find out the hard way, so either way, good luck with your project.

Jeff Yago

Share this entry

Jeff,

Criss

Criss:

Since solar and wind projects are still very new to some people, and these people are on city boards and in other organizations that make regulations, you will run into this from time to time.  It sounds to me like they do allow wind turbines, just not the type you were planning to install.  It also sounds like you really want a wind turbine.

My advice is to ask them what type of wind system they would approve, then install that one.  It may not be your first choice, but it sounds like its that or nothing, unless you want to spend big bucks fighting city hall, and still may not win.

Good luck,

Jeff Yago

Share this entry

Just found this site tonight at work.

I’m a pretty competent diy’er (carpentry, basic electrical, plumbing, etc).

You may have answered this before in the magazine (never heard of until tonight).

I live in Eastern Wyoming, outside of town on a west facing rise, and we have lots of wind. Blows most everyday 10-20 mph with many times throughout the year windstorms of up to 90 mph gusts.

I have a 76 14×70 mobile home, I have built around and wired. My well is 500 feet down and pump is about 400 feet down. I am single and 60 yr old.

My dryer is 220 and 5 year old (rarely use it—–hang dry). Refrigerator is 5 year old 110 volt average household size. Washing machine is brand new 110 volt.

Phantom current draws from, digital clocks on coffee maker, 110 volt microwave, tv, vcr/dvd player. I have two laptop computers both on 24 / 7

Standard mobile home furnace with blower and a 110 volt augur driven pellet stove (main heat). Propane water heater

As I am working in and on house, I use skil saw, tabletop, router, small air compressor, etc (one at a time)

Have already installed low energy light bulbs, most times only one or two are on at a given time.

I am considering going to wind and or solar energy alone or as supplement., and I have a couple questions if you can help.

1. Realistically in a 10-20 mph wind, how many rpms could I expect from a wind turbine?

2. Batteries, how many and what type / size, if used to support the whole house as needed (course I could switch back to grid, if heavy usage required it)

3. If wind turbine, how big a generator would you recommend (ac or dc out put and amp / watts)

4. Same for solar panel.

5. Power inverter, should batteries be wired for 12, 24 or 48vdc

6. Utility company requires an auto cutout if backfeeding to the grid, in case grid goes down. Is there one that would allow the generator / solar to continue to feed house, but not the grid if the grid goes down, and then refeed the grid when grid comes back on line?

Thank you for any assistance you can give, and I will continue my research.

SJ Launer

SJ:

Lots of questions and as a new reader I need to remind you and other new readers that we try and stay with general type questions since not all specific details are know or given to allow a more specific reply, nor do we have the time on a free advice basis. However, this should give you a good direction to head.

If you are in an area with a good constant wind most of the year then a wind system may be your best bet, but I caution that many people think they have lots of wind when in fact its not enough to justify the cost of the equipment. A good indication is if there are others in your general area using wind systems. Its good that you have minimized your electric loads, and that should always be the first step.

We don’t size wind turbines on a RPM basis. All modern wind turbines are sized to provide a given “watts” output for a given wind speed, and very few models can produce any power under 8 to 10 MPH. At 20 MPH you mentioned is a good wind level for most wind turbines, but you will most likely still need to raise the turbine at least 50 or more feet above the ground to really make it cost effective as the wind is almost double the ground speed as you get 50 to 100 feet above the highest nearby trees or structures.

There is no “generator” as separate from the wind turbine. This comes as a package, with the number and diameter of wind turbine blades matched to the internal generator section. Many turbines also include an internal voltage regulator for direct connect to batteries, while larger models have a separate voltage controller installed near your batteries. There are many different models and types, including direct grid connect inverters specially designed to take the DC or “wild” AC voltage from a wind turbine and match it to the 240 volt AC grid connection to allow selling all generated wind power back to the utility.

If you want the system to provide power without the utility grid, your system will require batteries and a DC output wind turbine. A separate DC to AC inverter is then used to supply your critical electrical loads from the wind charged battery bank. The size of the wind turbine depends on your pocketbook and the size of the battery bank. The size of your battery bank depends on the size of your pocketbook and how many hours or days you need to power your electric loads without the utility grid. Most systems end up being sized based on how much money you are willing to spend, since you will use all the power generated.

Remember, these are 2 separate wiring systems if you want to power your home without the utility grid. The battery bank supplies the AC inverter which supplies your critical loads, not all loads. The separate wind turbine and charge controller re-charges the battery bank.

Good luck!

Jeff Yago

Thanks for the response. I am still evaluating wind turbine versus Photo voltaic.

Thanks for your time.

SJ:

All utilities that allow grid tie sell back of power require this, but its not a “switch” as you suggest.

You need to buy a DC to AC inverter that carries these ratings on the label, UL 1741, IEEE 1547, IEEE 929.

These indicate the inverter will shut down and not sell power back on the grid if the grid goes down, and will not anti-island which means it will not be fooled by sensing other inverters also connected nearby and think the grid is still active when it is down.

You can use about any wind turbine that will charge a battery bank then use the battery charge to supply the grid through the inverter. They also make several inverters that are designed to take the ‘wild” output from a wind turbine and convert directly into grid power without a battery bank, but you need to make sure the wind turbine and inverter are matched correctly.

Hope this helps,

Jeff Yago

Share this entry

Jeff,

Do you need any special equipment if you want to add a wind turbine to an existing photovoltaic system (other than the turbine and support system for it)?

Bill Hiltscher

Bill,

Older model wind turbines required a charge controller to regulate the charging current going to the batteries and to provide a way to load up the turbine to reduce over-speed in high winds once the battery was charged and there was no load on the unit. The solar charge controller and wind charge controller can be used together and even charge at the same time as they do not allow for one charger “back-feeding” into the other one.

Some newer wind turbines include built-in electronics so you do not need a separate charge controller, and even newer models put out 120 VAC which can go straight back into the grid without charging any batteries.

Hope this helps,

Jeff Yago

Share this entry

Hi Jeff,

Hugh:

Sounds like a wind turbine will work really well at your location. However, larger models like you are looking for will require a very tall and very heavy tower. Also, servicing a wind turbine on top of a 75 foot tower is not for the meek.

If you do not want to install this heavy tower, perhaps you might consider installing two (2) smaller wind turbines which can be “tilt-up” type towers. They may be just as tall, but can be raised and lowered without climbing.

I have on client with two 500 watt wind turbines on his farm house, and another client that has two 1,500 watt turbines on his greenhouse, both trying to avoid a major steel structure standing near their home.

Otherwise, for a larger system you will need a regular installer with a very tall crane, and have some type of service contract.

Good Luck,

Jeff Yago

Hi Jeff,

Hugh:

If you have to run DC wiring very far, you want to have it as high a voltage as possible. If this will be a battery based system, you would want a 48 volt DC system, and keep the wire run under 200 feet or you will need a really expensive and large size copper cable.

You use a DC to AC inverter. Check out Outback and Xantrex brands. Most are 120 volt AC output, so for 240 volt AC you will need two identical units or a 120 to 240 volt transformer.

Try http://www.backwoodssolar.com/

Good Luck,

Jeff Yago

Share this entry

Jeff,

David:

There are several things to consider. No matter how good the battery type and brand, if the battery bank is undersized in reference to the output of any wind or solar input by having too few batteries, it will not be able to absorb a given day’s worth of wind or solar charging, and will not be able to carry the load until the next charging process starts. If a battery bank is oversized with too many batteries regardless of type or size, your wind or solar system will never be able to get them back to a full charge once they have been discharged, and each day the batteries will get lower and lower until totally drained. The number of batteries they are proposing (total amp-hr rating) is almost as important as the brand or model.

Although I believe Trojan Battery Company was the first to produce a model “L-16″ battery, this is now considered a generic physical size of battery just like we say “Jello” when we refer to almost any brand of gelatin. All industrial battery companies now make an “L-16″ size battery, but they do not all have the same amp-hour charge capacity or discharge rating. Each manufacturer will use a different mix of Lead-Antimony or Lead-Calcium in their plates and each combination will result in a different battery performance. While one combination may result in longer life, it may have a faster self-discharge or more out-gassing during charging. Another combination may result in stronger plates or a higher energy density, but take longer to re-charge or require higher charging rates that some wind or solar systems cannot maintain.

In other words, I would say in general almost any “L-16″ battery would be a good battery for a small residential size wind or solar power system, but these batteries can very greatly in amp-hour capacity, re-charge time, out-gassing, and rated life from one manufacturer to another. I have had very good experience with Trojan, Decca, and Concord deep cycle batteries, although I am sure there are others just as reliable.

Good Luck,

Jeff Yago

Share this entry