Billy's Wind-Talk Blog

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Average wind speed for 59 years    

Note: Most wind generators start generating at 9mph, and are at full load at 16 mph

May 28th 2009: Problems with wind turbine #2

At 3:45am a thunder storm passed through our area, for a period of 24 minutes winds exceeded 30 mph reaching a max speed of 41.1.  At this point we do not know if the generator was damaged of if the wire from the generator to the controller shorted.  A visual check of the generator with telescope does not show any black that would indicate a problem.  The wire from the generator to the controller on the 2kw system is #10 rated at 30 amps.  With wind speeds at 30mph the calculated watts should be 4.9kw or over twice the rated kw of the generator, or about 41 amps.   At 41mph winds the unit puts out 12kw or 105 amps, the wind was above 35 mph for 15 minutes, the average wind speed of 38 mph or 10kw at 120 volts is 83 amps.  This overload on the #10 wire will cause it to get very hot and perhaps short. 

If the generator is not damaged all the wire between the generator and the controller will need to be replaced with a min wire size of #6, to handle the excess power for the short periods of high wind. 

Generator #1 did not experience any problems, this may be due to the fact that the wire between the generator and the controller is much shorter.

May 26,2009 Complete system at Santa Maria scheduled to be 100% operational by end of June

The new 5kw 120vdc/240vac inverter has been ordered, the energy building is scheduled for completion by the middle of June and the control system software is coming out of the planning stage, and into code.  We have install the wind speed meter and the computer is now logging the wind speed.  This summer will be the test, look at the average wind speed and projected system generation for July, Aug. and September these are the lowest wind months of the year.  A new product for July will be a 50' inexpensive stand-alone tower. 

May 15,2009   Low wind operation:

Yesterday evening we had a wind of 6-10 mph, battery voltage was 125vdc and the house load was 1500 watts.  The charging amps to the battery pack was 2-5 amps, this is a reading from 2 wind generators of 1 to 2.5 amps each.  At the low end 120 x 2 = 240 watts at the high end 120 x 5= 600 watts.  Low end 1500 - 240 = 1260 watts from the battery pack.  High end is 1500 - 600 = 900 watt from the battery pack. Even at the low charging rate of 2 amps the load on the battery pack is 15 amps on the 120vdc battery pack. At the charging rate of 5 amps the amp load from the battery pack is less than 10 amps.

The wind was down for at least 10 hours, the battery voltage when the wind came back to 10-16 mph never dropped below 120vdc.

High Tec Energy is currently working on a computer program that will be able to calculate the minimum load required for the system and add or decrease the load as required.  In low wind situations where normal usage is not required, the software will reduce the load to maximize the charging rate to the battery pack.  Normal usage in low wind the software will maximize the management of the battery power.  In high wind situations the software will increase the minimum load to match the charging rate needed for the battery pack, if the normal load is below the new minimum load the software will increase the power consumption to the required level.

May 12,2009  I decided to calculate the  yearly generation of our system at Santa Maria, TX.  (see the chart at top of page)

It is a 6kw system that supplies a 1200 sq.ft. house. Using the 59 year average wind speeds, using the formula (watt=(sq foot of blade area * ws3*.0054).  For our area with central air conditioning the kwh looks about right.  I used the .145 per kwh because that is what I pay at the office.  Take note that the generation is the kwh usage only, it does not include the line service charge, or any taxes on the usage.  Lets look at May because we have been conducting load tests on a daily basis for the past 11 days.  I have found that for the past 11 days we have used on the average of 60 kwh per 24 hour period.  Lets take that daily average and multiply it by the number of days in May  (60*31)=1,860, this is about 1/2 of the May generation.  This is running all the lights, air conditioners, and appliances 24 hours a day.  Even with our full load test the lowest month would be 613 kwh short.  By using a good energy management program for the house I can reduce its consumption to 1000kwh per month.  Now the low months generation fall well within the consumption.  It takes about 3 days to recharge the batteries when they drop below 90vdc.  This you do not want to do, if you cannot stay within the safe area of your generation then you need a larger system.  Using the generation alone this system will pay for itself in about 8 years, that is if the cost of power is not increased.  At least that is what the numbers say.

May 08,2009      Just some notes on the load testing

For the past week the system testing on the Santa Maria project continues.  The system is real stable, with battery voltages ranging from 135vdc to 121vdc.  These are 600 ah batteries (1) 48volt and (2) 36volt in series to make 120vdc.  The batteries are rated for a 360 amp load for 12 hours.  With an estimated 518,400 watts, full load on the house with everything running, HVAC, Drier, all lights, washer, refrigerator, television set, iron is about 6000 watts or about 15,000 watts per 24 hours  518,400/15,000= 34.56 days.  This is how long it would take to run the battery pack below 90 volts dc, if the wind does not blow or the turbines are turned off.  The question is when do you run all the appliances, & lights in your home all at one time, an when do you do it for 24 hours.  Large industrial batteries are they only storage you should use on wind systems.  The USDA says that you must have a 20ah backup,  that is not enough and will cause you problems with power outages.  To sustain the power on a conventional home a backup of 600 ah in a min, the packs we sell start at 750 ah.  Note when you place batteries in series you do not increase the rated ah. 

May 6, 2009    Off grid living:

When electric power is used by lights or appliances, it really does not matter to the consumer where it comes from, they want the light to come on or the appliance to work.  You really need a system that will supply all your power need on demand.  What is happening is, 1. systems are undersized because of price restraints, this leads to an inadequate supply of power.  A system that supplies an inadequate supply of power will not be cost effective.  In a newsletter I received this morning a system had an annual savings of 23%.  A well designed stand-alone system will give you a savings of 100%.  Do not be duped by the so called grid-tie, if you think you need backup then a transfer switch or a backup generator.

There are a few things you need to keep in mind about stand-alone systems.  They do require a constant load, this is your min load.  So you run the air conditioner more or you water the yard with your well more.  Your battery pack will require water each month, the equipment will need service.  But you know all about service if you own an automobile, you know you change the oil, keep the proper amount of air in the tires, wind power equipment is the same.

The great fear: The power goes off, right now with the drought and dust the grid is down at least once a week.

With the grid I have unlimited power:  Go outside and look at the transformer on the pole, nine times out of ten you have a 10kw transformer.  You do not have unlimited power you have 10kw.

May 5, 2009      Available power

I am rethinking the design of a stand- alone system.  By using a larger inverter min 5kw on homes up to 1200 feet and 10 kw on homes from 1200 to 2000 sq feet.  You will not need anymore wind power than 2 kw in low wind situations, and 2 kw in high wind, but the extra power provided by the larger inverter will take care of any lock-rotor needed to start motors.  Even if your are charging your battery pack with a 2kw generator the runtime above 2kw is not enough to drain the battery pack.  On a normal home during the day most of the appliances are cycled or shut off.  The system we are installing in Santa Maria has 6kw of wind generators in 2kw units.  With 3 2kw 120 volt ac inverters to handle all the lighting and the wall plugs and a 5kw 240 volt ac for the central air conditioner.  These could be replaced with (1) 10 kw inverter to power the entire house.  The 10kw inverter will only load to the max load of the house.  While 80% of the time the house load is below 50% the smaller wind generators keep the battery packs at max power.  In the demo house we are using rated power from the wind generators of 6kw while using 11kw of inverter power will charge the battery pack under normal wind conditions of 16mph.  The extra 5kw is used for momentary peak.

The idea is to build a system that will have enough capacity to power your home, without too much interruptions.

May 4, 2009

Saturday May 2 we conducted a full load test on the wind system.  8 hours of full load on the house, lights, refrigerator, air conditioning, television, exhaust fans, cloths Iron. Started at 12:00 noon and ended at 8:00 PM.  Starting wind speed 20mph, starting battery voltage 140vdc.  Ending wind speed, 16 mph ending battery voltage 135vdc.  For six hours only (1) 2kw wind generator was used, in the 20mph wind battery voltage ranged under full load from 130vdc to 140vdc.  As the wind speed decreased in the evening the second generator was started and maintained the batteries with 135vdc to 140vdc or floating charge.  Specific gravity on the batteries stayed in the green the entire time.   In 8 hours the system generated 25kwh. 

Sunday May 3 the wind speed between 10 & 15 mph the house was operated as normal.  Only lights needed, refrigerator, attic exhaust fan and air conditioner, & television.  In this low wind situation the batteries maintained a voltage of 125vdc, specific gravity stayed in the green entire time.  Yard light and outside porch lights turned on at dusk and stayed on to Monday morning.  Low (5mph) wind all night only 80 tower turning at 7:00am Monday.  Battery voltage at 128vdc.

This is a very stable system both at high wind situation and low wind.  System must be able to operate at both ends of the wind speeds.  At high winds be able to store the generated power and not damage generators, at low wind generate enough power to maintain the batteries at full charge. 

By investing in an adequate stand-alone system, with proper maintenance you will have years of uninterrupted power to you home. The same 10kw as the transformer on the pole. 

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