Ken Hall's posts

“Maybe a marine switch panel is not the best tool for the job either?”

As Thomas pointed out, the answer to that is dependent on your criteria for your system.
Is it Workable and safe ? Or, Code compliant (NEC), workable, and safe ?

Your marine switch panel is not code compliant for a dwelling. Neither are most RV devices.

While flux core solder will usually produce an adequate joint, I prefer solid solder. Applying liberal amounts of a non-acidic flux to the lug and wire before applying the heat and solder will consistently yield better results. Wire brushing of the inside of the lug before fluxing, is also a good idea.

You don’t know how many watt hours you intend to use and you do not know what size batteries you have.  You feel you are OK because the batteries have served you well in the past.

Step one in the proper design of a solar system is determining how many watt hours you intend to draw from it on a daily basis. (The AltEe university has a calculator that can help)
Step two is sizing the battery bank to support that load, including any reserve that may be factored in.
Step Three is sizing the panel array.
You are apparently doing it by “got my batteries, ordered my panels, will worry about watthours later”. (A lot have people have done that, and end up paying for it later.  They “fry” or “smoke” the batteries.)

Batteries will accept certain loads under occasional use (such as RVing) that are abusive when done 7 days a week, 365 days a year.  RV/Marine batteries are not true deep cycle batteries, and do not stand up well in 7/365 service.

Unless Sears has some battery I am not aware of, your 2 battery bank is about 200 amp hours (plus or minus about 10%).   That is a terrible mismatch with your 800 watts of Panels.

While I wish you the best of luck with your new system, I fear that you will be buying batteries much sooner than you expect to.

Ken

"So, do you think the problem is because of the Modified Sine Wave, or the fact, that it's a half voltage scheme?"

There isn't enough data to really make that call.  Thats why you might want to call the tech support group. Or, try testing the device in various inverters if you want to sort out the problem.

Otherwise, just insure that the new PSW is not a half voltage scheme.

Dave's idea about running directly is a good one. But, I also know that a lot of alarm systems run on a 6vdc battery.

I am curious about the adapter getting hot and how you determined that the MSW is at fault. Many of the smaller inverters are half voltage schemes. Try measuring the hot to ground and neutral to ground on your inverter. See if you come up with 60V on each.

I am not discounting the MSW being at fault, but I can also see how a half voltage scheme might raise heck with some electronic power supplies. It might be worth a call to the alarm mfg tech support group to see what they think.

If I could not get a handle on which is more likely to be the prime cause of the problem, I would make sure that the PSW inverter is not a half voltage scheme.
From the manual, the XP125 appears to be full voltage, but I would want to confirm that before purchasing.

 
 

I think if you supplied more info, it would be easier to respond to your questions. 
How many watt-hours do you propose taking out of the batteries “to reduce some power costs?  On a foggy day with less solar, will you reduce that figure, or do you need a reserve ?  What Is the figure (watt-hours) for backup power on an occasional basis ?

What make and model is your inverter and how are you going to supply the power to the house ?  Are you attempting to connect it into the house wiring or just running extension cords ?

Just how big are your two large batteries and are they true deep cycle batteries, or are they “RV deep cycle” ? The make and model of them will give us the answer if you don’t know.

What is the general location of this system ?  We need to know the hours of full sun.

With answers, I think we can give you better recommendations.  Right now there is enough gray area that it is hard to say anything.  The batteries in the RV indicate that you are probably thinking 12Vdc, but you might be better off with 24Vdc.   

CFL's can be a little quirky, especially when they are the only load on a MSW inverter. To test that, try taking a normal incandescent 35 watt bulb and running it. See if it goes longer than the 6 hours.

Rainwater cisterns are generally considered as non-potable in the US. Have you looked at county health department/OSHA requirements for this shower facility, to determine what water treatment might be required ?

Max

I wish you had posted the make and model of the turbine.
Is it really designed for 2-6 blades, or is it a 6 bladed machine and you are thinking of removing four ?

Removing the 4 blades will increase the loading on the remaining 2 blades.  If not designed for it, a failure at the blade root/hub would be likely.
I am not sure that you would be getting an increase in self destruct speed. You could actually be lowering it.

You will be lowering the output across all wind speeds.
 
Without any specific info, I would say leave the base design alone and concentrate on adding a furling and/or braking mechanism.  Can it tolerate a shorting switch ? Or consider a tilt up tower and lower the turbine when high winds are forecast.

Ken

Concrete isn't a problem.
In my area, Ufer grounds (concrete encased) are common.

(3) Concrete-Encased Electrode.
An electrode encased by at least 50 mm (2 in.) of concrete, located within and
near the bottom of a concrete foundation or footing that is in direct contact with the earth, consisting of at least 6.0 m (20 ft) of one or more bare or zinc galvanized or other
electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (1.2 in.) in diameter, or consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 4 AWG. Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means. Where multiple concrete-encased electrodes are present at a building or structure, it shall be permissible to bond only one into the grounding electrode system.

The OP's pole does not meet the requirements as a ground rod or a Ufer.

The zinc plated steel mentioned by Tom is not accepted by our local authorities. It must be copper clad. The testing for a single rod is too much of a hassle to deal with. So, you drive two, or use the Ufer.

There are two types of the “old fashion pump” out there. One is called a pitcher pump.
It is good down to about 22-25 feet, depending on your altitude.
http://www.survivalunlimited.com/handwaterpumpshallow.htm

The other is a deep well hand pump.
http://www.survivalunlimited.com/handwaterpumpdeep.htm

There are a lot more sources out there. Google away.

Ken

What size generator are you thinking about and how many gallons per hour of fuel does it burn ?  Even with a small one, your cost per gallon (or 100 gallons of water) moved will be substantial.

Most small generators are not designed for 24/7 operation over an extended period.

I don’t have any experience with the Shurflo 9325.  But since they only talk about it running on solar and I did not see a mention of batteries, I would want to talk to Shurflo about the life expectancy in 24/7/365 operation.

Between the fuel costs and possible short lived equipment costs, I would buy a pump suitable for battery operation on a 24/7 basis.  The batteries could either be charged by a few hours of generator use, or even better, with solar panels.

There are plenty of AFCI problems without an inverter.

"Loose plugs" can cause tripping. Make sure the plug/receptacal fit is tight.
Shared neutrals.
Multiple electronic ballasts. (Too many CFL's would do it)
Surge protectors that have reached the end of life. (MOV leaking excess current to ground)
RF noise

Ken

The wind speeds that you listed are not favorable for any wind turbine.
A single 100 watt solar panel would produce more power than the wind turbine.

Ken

I would suggest you move it a lot closer to the house. 
It will save you big bucks.

You can always build a fence or plant some shrubs to shield the view.

I am curious about the grid connection.  What is the AC voltage and frequency ?

If you have to have plug in capability, I would use an appropriate sized SO cord between the AC panel and the inverter. If you install a 4 prong twist lock plug in the middle of it, you are now plug in capable.

Portability has nothing to do with the idea of unbonding the neutral, and putting 60 volts on it.

Mike:

The term floating neutral is often used to describe a system where the neutral is not bonded to ground.  Others also use it to describe two hot leads and a ground, with no neutral.

That is what the half voltage scheme inverter is. 60 volts on the hot, 60 volts on the “neutral”, and the separate ground wire.

The ground supplied by the inverter will probably be at a different ground potential than any other grounded item in the cabin (meaning water pipes or other conductive items with a direct path to earth.).  Between the different ground potentials and having 60V AC on your white wire (and other things that should be “neutral”), don’t be surprised if there are more shocks with this method.

Don’t count on protective devices to work properly.

You will never be able to interface it with a generator, or any other power source. (Other than running them through a charger to your batteries)

If you have fire insurance and the place burns, the insurance may not pay if the non-code system is discovered during the investigation.

Some people may point to a 230V system and say that the two hots and a ground have been used safely for years.  The difference there is the second hot is red and both hots are breaker protected. (And most homeowners are scared to death of 230V, won't get near the plug)
You would be using the whites as hots, without having breakers on them. That could easily start a fire, or cook your inverter.

Keep your panel grounded. It is much safer. Get a proper inverter for your system. 

Ken

Mike

Look on page viii, in the manual.
The second item under the Equipment Damage Caution.
"Do not connect any AC load that has its neutral conductor connected to ground to the XPower inverter."
The same warning is repeated on page 5-3.

While Xantrex could put that in language that might be clearer to everyone, that clearly indicates that they do not want it connected to a 110v electrical panel.

(not to mention that on page 1-1 they say "The XPower 1500 is a quality inverter designed for recreational vehicle
(RV) and truck applications.".)

Here is the Xantrex FAQ on the subject.
http://www.xantrex.com/support/readfaq.asp?did=253&p=1609


Your 110V system either has a ground or it doesn't. The normal place for it to be grounded is in the panel. The neutral bond is there.  But a ground anywhere on the 110V system (even to a metal water pipe) would make that neutral/ground bond active.  Without a ground somewhere, all you have is a neutral with extra metal in it.

(Whether or not you grounded the inverter chassis is a seperate issue)

Ken

The Xantrex power pack UL approval is as a portable (temporary) power inverter. It is for plug in use only. If you attempt to use it as a part of a permanent system, it would be a NEC code violation.

While I have never used it, it appears to be a half voltage scheme inverter. Assuming that it is, if you ever connect it to a standard 110V system with a neutral bonded to ground, you will either smoke the inverter or cause other severe equipment damage.

If you want to go beyond plug in use, look for a different inverter.

Ken

Have you ever heard of the Betz limit ?
You might want to compare that to your effeciency.

Anway, the 200 watts is real close to the exploitable potential of kinetic energy in the flow. You are not going to get anywhere close to that as shaft power, particularly at the slow flow speed.

Somehow I think you picked a thesis subject that was fairly far removed from your study area.

How you calculate rpm is dependant on the design of the turbine and the design flow speed, which you stated is about 1 m/s.
If this is some type of shrouded water wheel, it is linked to the circumference of the turbine wheel. If this is a true turbine (e.g. Pelton) it depends on how much acceleration you have in the nozzle, and the circumference of the wheel.  If it is a propeller design, it would be linked to pitch of the blades and circumference.
You need to get the unloaded or theoretical rpm, before arriving at the loaded rpm. The loaded rpm of the shaft and generator output curve determine how much gearing you will need.

How did you arrive at your 200 watts (which I presume are mechanical), if you don't know the rpm ??

First of all, discard the idea of a car alternator.  They are only about 55% efficient in converting mechanical power to electricity. They also require a high RPM. Your gearing losses will be tremendous.  While junkyard alternators can be used when you have excess shaft hp available, I don’t think you don’t have any margin to spare.

As far as off the shelf items, your best bet would be a PM (permanent magnet) DC motor. Look for one with a low rpm rating. That will help keep your gearing losses down.
(from your limited description of your turbine, I suspect that you have a low RPM on the turbine shaft.)

Another course would be to build your own PM alternator. There are a number of examples on the fieldlines site that Thomas referenced.  Another is Hugh Piggott’s site. 
http://www.scoraigwind.com/
Or, Google away.

While car batteries will work for the purpose of your thesis, they are not suitable for storing any significant amount of power for an alternative energy project.  One of the biggest stumbling blocks is the cost of decent batteries.  No matter how inexpensive a power source is, the cost of energy storage will usually kill it, when you are competing for those rare development dollars.

A diversion load does not generate any power.  It burns excess power, to keep that excess from smoking the batteries.  A diversion load would be a necessity, if your thesis ever moves into the real world.

You might consider modifying your project.  If you designed an inexpensive positive displacement water pump, which could be powered by your turbine, it might have greater application.  Moving water without an associated fuel cost, is one of the larger problems in many developing nations.

Thomas:

I wish there was an advertised trade name, or a requirement that they be plainly labeled as half voltage.� 

Most of these used to be square wave, many are now modified sine wave. One of these days, I imagine they might even creep into the true sine wave. I haven't seen one yet, but they might exist.

Here are the Samlex FAQ's on grounding and bonding inverters. Numbers 10 and 11 are on point.
http://www.samlexamerica.com/customer_support/faq_06.htm

As far as telling them apart, I would treat any inverter that did not have hard wire terminals (receptacles only) as suspect, until proven otherwise.�  Many have instructions that say the inverter is not to be wired to a distribution panel, plug in use only.�  (But who reads instructions, anyway ??)
The ultimate test is a volt meter.

Ken

I think that we are going to find that Mike's 1500W inverter is an inexpensive half voltage scheme inverter.  And, his 110V panel is grounded, with the neutral bonded to ground in the panel.
So, when he plugged it in, he was pumping 60V into a direct ground. Flash, bang.

Half voltage schemes are a good reason that you should avoid plug in cords (power source) to a distribution panel. Although it is not as dangerous as a cord with male plugs on both ends, it is still a "suicide cord". If you want to use a distribution panel, make sure your inverter has connection terminals for a hard wire scheme.

Mike:

You need to give us the make and model of your 1500W inverter. That will help clear up a number of things.  If you also tell us the make and model of the 1750W inverter, it will make it possible to really tell what the differences are.

Ken

I am assuming that you meant a 14 foot Aeromotor.

You seem to be separating the mills and the turbines by the end work performed.  While it is true that windmills are best at mechanical tasks and turbines are usually making electricity, that is not what separates them.  Windmills can generate electricity and turbines can pump water.

Windmills are drag machines. Their “sails” or blades are pushed by the wind.  There is very little or no lift generated by the blades.  Turbines use airfoils that generate a substantial amount of lift.

Your belief that HAWT’s must be pointed upwind is incorrect.  While the majority of them are upwind machines, downwind designs do exist. Here is a good write up on some of the differences.
http://www.windpower.org/en/tour/design/updown.htm

Lets try it a different way.
You have what is approximately a 3/4 hp electric motor.
If you reduce it to 1/20 hp, it will not do the work.
You need a 3/4 hp motor, regardless of voltage.

Here is a 12v dc motor (3/4 hp) that would come close to replacing your AC motor.
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200381907_200381907
I am not sure whether the rpm is a good match or not.
But note the power draw, 58 amps.

No matter how you try to get around it, you are going to need a motor that pulls 60 amps plus or minus at 12V.  Or you are significantly reducing the cooling capacity.

Do not get too hung up on CFM numbers. You can have 2 fans that move about the same amount of free air, but one will drop out quicker when you expect it to pull a partial pressure. CFM numbers are often about as accurate as EPA mileage numbers used to be.

By the way, you better go read your bilge pump again. If your amps are correct, it is a 450 gph (gallons per hour) pump.  That would make it about 7.5 gpm. And that rating is at 3 feet of water or something under 1.5 psi.  Put more back pressure on it, and the numbers fall off rapidly.

I don't believe anything on youtube.

I also don't know how you can expect 100 watts to do the work of 700 watts.
My suggestion would be that you do not do anything in your conversion that would make it difficult to revert to the original configuration.

In fact, if I were attempting it, I would build a test cooler first. I would buy some smaller evap pads and mount them in a box with a fountain pump. Mount the fan and duct it into one room. See how it works. Power the thing with a battery or 12V power supply.

If you were to modify your original cooler with the radiator fan, I would guess that you would only get about 10% (or less) of the current cooling capacity.