HELLO
Interesting subject on which I have already worked, I would like to clarify some basic data which seem poorly understood:
KV : This is the MAIN characteristic of the alternator or three-phase motor that you will use as an Alternator. It is therefore the first criterion of choice.
Quézaquo?
It is a coefficient (without unit therefore) between the speed of rotation, and the voltage of the engine / alternator. Example, a KV of 100 gives 1000rpm under 10V. Simple, right?
Normally it must take into account the "electrical slip", that is to say the loss of rpm under load.
So our engine / alternator must give 10V at 1000rpm, at its nominal power. This is not always the case, and some Chinese in particular give it up. In this case remove 10% and it should not be very far.
A brushless motor with permanent magnets can be used as an alternator with a three-phase rectifier bridge behind. Ex: Hobbyking motors, VAE wheel motors, brushless motors on certain washing machines (directly connected to the drum).
A wind turbine, depending on its size, rotates from 500 to 3000rpm approximately, of course there can be extreme cases outside.
So to work live, we will aim for say 1000rpm to have the minimum voltage sufficient to start charging.
In 12V there is therefore a KV around 100, in 24V around 200.
To test it it's quite simple, rotate at a known speed, and measure the voltage with a voltmeter, divide.
The recovery engines / alternators suitable for wind turbines are rare, because of the KV which is too high in general.
Ex: automotive alternator rotates at 5 rpm for 000V, 15 rpm max. A belt reducer will make noise and lose a lot of efficiency.
Ex: The brushless washing machine motors are suitable (LG, SAMSUNG, some Whirlpools), but not those reduced with a belt (these take 10 rpm and are charcoal)
In model making motor it is quite rare and only the big motors they are all higher KV. Or high efficiency drone motors, or "guimbal" motors to direct cameras. Almost any eBike wheel hub motor is suitable, since a bicycle wheel spins at roughly the same speeds as a wind turbine.
Then the second dimensioning criterion is the power, always over-dimensioning, for example a brushless motor of 1000W under 24V kv100 is dimensioned to support 1000W / 24 = 42A roughly. This will make a good 500W alternator, it will work with a better output at 20A. The regulator will also have to be oversized.
You will understand that it is important that the wind turbine has the lowest possible speed range (not variable)
Otherwise between 1000 and 3000 rpm, the charge regulator will have to collect 3x more voltage to charge the battery.
If it is a PWM, it will heat up, loss of efficiency.
IF the wind turbine goes into overspeed, cramage in sight.
Without variable pitch, compulsory active orientation (feathering), (except turbine any direction of course, but which all have a lower output)
Good research, I am ready to analyze any find that you will make to determine the best conditions of use.
