The first part of the article caused an active discussion in the comments, in addition, a Peling colleague pointed out one of my mistakes and the story was continued, which I will tell you about later.
The first part of the story is here .
When in the first part I talked about the low generation of the generator, the comments suggested that the wire cross-section was 3x2.5 mm2 insufficient for its length of 100 m, which led to large losses at low voltage that the generator gives out in light winds. A link was given to a calculator for calculating losses . The link is undoubtedly useful, but many commentators have not taken into account the nuances of the operation of the generator of a wind turbine with different wind power and different power output.
At the same time, ideas were proposed to increase the output voltage of a wind turbine to 220-380V for transmission through a thin line with either a three-phase transformer or a DC-DC boost converter. But those who proposed did not take into account the fact that the voltage of the generator of the windmill and its frequency can fluctuate over a very wide range - which cuts off all simple and cheap solutions.
Specifically, the voltage of the generator of a windmill can range from 10 to 110V, at 45-55 V in the wind 12-15 m / s, which is in one of the recent videos of a Peling-a colleague with a windmill of the same model as mine.
Watch here.
My mistake with the windmill is as follows - the Chinese sent the windmill controller to the 12V system, and I connected it to the 24V system and the controller believing that the batteries were charged slowed down the windmill. The error is, of course, a gross one, but the markings on the controller are really “crooked” - it looks like 24V operation is noted, but in reality it only works on 12V.
in
Realizing my mistake from the Peling prompt that ran into the same problem, I rebuilt the system in the 12V version as a clean stand. Windmill -> Charge controller -> Wattmeter -> Battery 12V 170 Ah without any other current sources or consumers. Then he shot a video with the “clean” readings of the power meter, so that you could control the actual production of the windmill for a certain period of time.
First video dated 01.11.2019
Second video from 09.11.2019
The nuances of the operation of small wind generators are as follows - the voltage that the generator of the wind turbine gives out and the power output is highly dependent on the speed, and the speed of the generator depends on the wind power.
At low revs, there is little voltage and the output current, usually it is about 10-12V at a current of 0.01-0.1A. With this voltage, usually even the controller of the wind turbine does not give out power, because it is not enough to charge even a 12V battery and the power keys of the controller are closed. As rpm and voltage increase to 15-20V, the controller keys, if configured for 12V, begin to open and it starts charging the battery, giving off voltage of 12-14V and a current of about 0.4-0.6A at a power of 4-6 watts. But if the controller is configured for 24V and a 24V battery is connected, then until the voltage supplied by the generator of the wind turbine exceeds 25-30V, charging does not begin.
Now a little about the windmill controller. This is a fairly commonplace PWM (PWR) controller, at the input of which a three-phase diode bridge. A circuit for controlling the speed of the wind turbine and a circuit for monitoring the voltage of the battery are added to the circuit, which, when the parameters are exceeded, supplies voltage to the generator windings, braking the rotor. The windmill does not have a mechanical brake and braking is done in this way.
From the above it follows that at low speeds and power of the windmill, the current is small and voltage is small, losses in the 3x2.5 line are not of particular importance. And with an increase in speed and power output, the voltage increases, which leads to a decrease in losses on a long and "relatively thin" wire. A little lower my calculations in support of the reasoning, using the above calculator by reference.
1 case. Battery 12V, light breeze.
Calculator Options:
Alternating current
Material Copper
Line length 100 m
Section 2.50 mm2
Power
Load power 6 W
3 phases
12V voltage
Temperature 25C
Loss 0.353 V (2.946%)
As we see and was said above - at low power losses are negligible.
2 case. Battery 12V, medium wind.
Calculator Options:
Alternating current
Material Copper
Line length 100 m
Section 2.50 mm2
Power
Load power 50 W
3 phases
Voltage 25V
Temperature 25C
Loss 1.414 V (5.656%)
As we see in this case, the losses are not so great, everything is on the same 3x2.5 mm2 wire.
But when switching to a 24V system, the situation becomes even more interesting. The entire range of capacities at which the voltage of the windmill is lower than the charge voltage of the battery is cut off by the controller, and at operating voltages of more than 25V the line loss is even lower.
3 case. Battery 24V, medium wind.
Calculator Options:
Alternating current
Material Copper
Line length 100 m
Section 2.50 mm2
Power
Load power 60 W
3 phases
Voltage 27V
Temperature 25C
Loss 1.571 V (5.818%)
As you can see, in this case, the losses are not so great, everything is on the same 3x2.5 mm2 wire.
The following conclusion follows from this - a 3x2.5 mm2 wire in my case, even with a line length of 100 m, works quite well so that there are no unacceptable losses on it. You can lay a 3x6 mm2 wire, reducing the loss by half, but this will cause a rise in the price of the system, which is unjustified from my point of view. I did not contact the aluminum wire, because the line is laid underground and in conditions of high humidity, aluminum wiring quickly fails.
From all of the above, I made the following conclusions for myself - a windmill is a useful thing, but only if you have a constant wind. The keyword is permanent. It can be weak - 3-7 m / s, it can be strong 8-15 m / s. But he must be CONSTANT. Not gusts of "5-7 m / s" or "7-15 m / s", namely constant. And only then the installation of a windmill is justified. Because, the power given will be constant and the windmill can be optimized for the strength of the wind. But if you have gusts of wind and the windmill spins 5-15 minutes per hour or even every three days in gusts giving out 3-6 W and at the peak of 20-50 W - it will be just an expensive weather vane. And the most piquant - in Russia there is actually a constant wind in few places. These are either mountains and other high elevations, or coasts.
Now about vertical wind generators, which are supposedly more effective than classic ones. This myth was dismantled here by the person who “ate the dog” in windmills.
"Cherry Chupa Chups! or, the whole truth about a vertical wind generator. Part 1"
I fully agree with the conclusions of the author of the video. This type of windmill is only good when installing high-rise buildings on the balcony, provided that it does not interfere with its noise to the residents. In other cases, classic windmills are better.
So, dear comrades, you will make the choice whether or not to install a windmill, whether you’re ready to buy or do it yourself, based on conditions that are in the place where you live, just take into account my practical experience and do not literally throw money away especially if it’s not there.
UPD. In the comments here and on YouTube, a lot of adherents of building homemade windmills appeared singing the mantra "Chinese bullshit windmill, homemade rulez and give power even without wind!" But as a person who can work with my hands myself and was engaged in “collective farming” out of need personal experience I believe that they are wrong. And there are good reasons for this, especially in my personal case.
Reason number 1 is to build a home-made "the best windmill in the world" instead of buying good Chinese.
You are a rich person with income sources that do not require working for 200 or more hours a month, you have a lot of free time that you can spend on calculating and manufacturing parts of a wind generator, there is a workshop where you can make all the necessary details. For you, building a windmill is a hobby and self-realization from the process itself when the time and money spent is not important. as is the end result.
Unfortunately this is not my case. I have to work more than 200 hours a month in shifts of 12-hour day and night shifts of 17-19 shifts to get my 25-27K rubles clean. And I just do not have time to make a windmill with my own hands. It’s easier for me to raise money and buy a finished unit than to spend a couple of years of my life on a makeshift wind turbine.
Reason number 2 is to build a home-made "the best windmill in the world" instead of buying good Chinese.
Your conditions allow you to use a windmill, but standard designs are either too expensive - European-made, or can not work effectively - Chinese. This is either a constant but weak wind of 1-4 m / s blowing 24/7/365 a year that simply does not really spin Chinese windmills, or vice versa a strong constant wind of 17-35 m / s which takes the windmill into protection mode when the wind speed is exceeded.
In the case of a weak constant wind, you will have to count the blades under it of great elongation and a generator capable of working at low speeds. The step-up gearbox in such systems is usually excluded, there is too much power loss on it, the windmill simply will not turn in a weak wind. And it will be necessary to provide for braking systems in strong winds and sufficient strength and stiffness of the blades so that they are not broken by a sudden flurry or hit the mast by bending.
In the case of a strong wind, you will also have to count the blades, but on the contrary they work well at high wind speeds, thin, in large numbers and of small elongation, like marine yacht windmills. It is possible that if the speed of movement of the ends of the blades turns out to be close to sonic or even supersonic, it will be necessary to calculate and produce blades of a saber-shaped profile operating at such speeds.
In addition, in the manufacture of the blades and the “hub” of a homemade wind generator, it is necessary to provide sufficient strength, which without experience is not at all a fact of what happens. Unless of course you want to catch the blade with your skull, or so that the detached blade does not fly into the neighbor’s skull and you don’t go to prison for 7-10 years.
And another question - whether the blades of your windmill will make noise so that you break it yourself or whose neighbor got a nasty noise - it will break your face, and then your windmill.
It is only in these two cases that the independent calculation and manufacture of your own unique wind turbine is justified. In other cases, the sum is cheaper, and most importantly the Chinese windmill will be delivered faster, especially if you are unsure of the return on it and are not ready to risk putting an expensive European one.
And another small point - in the comments there were discussions about the propeller for a wind turbine with a mechanism for automatically changing the pitch. So, those who wish can study the epic with VISH in aviation of the 30-40s of the 20th century, and what technological problems were in the implementation of this system. The propeller for the wind turbine by adjusting the pitch, if it is not a 100 kW installation in a place with steady wind, will make the wind turbine “diamond”. A bored millionaire can afford it, but unfortunately I do not.