Why doesn't my windmill generator seem to charge the batteries?

Hi there,

I figured Id post here because I have no one to ask and answers aren't obvious from googling.

The connection is as follows:

- (0 Volts to 40 Volts open voltage) Windmill to a 12 Volt Battery.

- (0 Volts to 20 Volts open voltage) Solar Panel to a 12 Volt Battery.

A solar panel has an open voltage @ 19.95 Vdc and delivering 0 amps.  The panel is not connected.  
Then I connect the panel to the 12 Volt Battery.  Now, the solar panel now shows a voltage of 14 V and delivering 2 amps into the battery.

That makes sense to me.  When connecting the solar panel to the battery, the system is now "on load", so the voltage drops.  But because the voltage drops, the amperage is being sent into the battery.


Now,  The windmill has an open voltage between 0 and 40 vdc.  On average it shows 20 volts when spinning.
40 volts when its faster.  Its known that it takes 14.1 volts to start charging a battery.  
So, now lets assume the windmill is spinning @ 40 volts open voltage.  

I connect the windmill to the battery.  For under a second, I see amperage go from the windmill to the battery.  
The amperage amount is 3 amps for 1/4 a second, 0.6 2/4 of a second, then eventually 0.
The voltage after connecting the windmill to the battery is the same as the battery voltage.  In my eyes, its not charging the battery, because amperage dropped to 0.

As a side note, as soon as I connect the windmill to the battery, the generator/turbine, also slows down in speed.  
I am also curious to know why it is slowing down as well.  

Anyone have any ideas?

- U

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useful1 (author) 3 years ago

But, I'm still unclear on why no amperage is being pushed into the batteries.

Voltage on the batteries should still go up higher, but its staying at a steady 12.1-12.2V with no amps going into the battery, in the case where the windmill is connected directly to the battery, bypassing the charge controller.

I am curious to hear more about this: the generator is just producing enough power to act as a break.

I quite dont understand this comment. Been wrapping my head around this one, I would like to hear more about this if you could elaborate.

Thanks in advance,

- U

useful1 (author) 3 years ago

The said charge controller for this setup comes from this instructable:


The way this charge controller works is by controlling two relays on the positive side. Negative/Common connections are all connected.

All incoming power is pushed through a power diode of a rated size depending on your system. Two relays control whether or not the power is turned off on the power inverter or to redirectly excess power into a heater element.

useful1 (author) 3 years ago

The windmill i'm using is being rectified from AC to DC.it is an aleko 450 watt 12v wind turbine. its a 3 phase ac wind turbine. 3 wires coming out, which im pushing into 3 single phase rectifiers which are rated at 100 volts and 25 amps each.

I've changed the rectifier on the windmill once already, but the results are still the same. 0 amps are being pushed into the battery. I've even tested it out by connecting the turbine directly without the charge controller for less than a minute.

The wind mill slows down when it is connected to the battery because it is under load.

The current dropping is ether the battery is charged, there isn't enough wind and the generator is just producing enough power to act as a break or there is something out in the electronics.

How is its diodes?

The battery is charged, that's why its not drawing any current

Replace the battery with some resistance, and experiment at measuring the power rating of your windmill.

+1 :-)

The generator slows because you are putting a load (electrical) on it. - It is doing work. There are electrical reasons as well but doing work is the simple reason.

I assume you have some kind of voltage regulator between the windmill and the battery??