Using MPPT to regulate Wind Gen?

[Canibul]

I think the internal regulator for our Air-X wind generator got blown in a lightning strike. I still get voltage from the generator, but it varies up and down with the velocity.

I'm wondering if I can just hook that up parallel to the solar on the imputs of my MPPT and add the wind gen to the rest of it?

Or would it be okay to just hook the unregulated wind generator directly to the batteries?

[Vasco]

I have hooked unregulated wind generators (Windbugger, KISS) directly to the batteries but I was always aboard when they were running and would shut them down if the voltage got too high.

[FSMike]

WARNING - I know nada about this but -

The wind generator I used to have always varied in voltage by wind velocity I thought the internal regulator was to shut down the Air-x when wind speeds were too high or the batteries were fully charged.

[Canibul]

Thanks for that input. We've just moved aboard four days ago, and have a constant DC load on the batteries now. I've installed a battery monitor, and we keep a close eye on it as our freezer fridge system ( Rich Beers) uses 26 amps to keep the freezer cold in a dual compressor setup.

I was wondering if running it through our MPPT or the PWM would protect the batteries from overcharging, too. In the meantime, we need the nightime top up while I figure out why our IOTA 55 amp charger isn't doing it on shore power.

Oh, the joys of working and living on an old boat when you're technically challenged.

[mitiempo]

A wind generator needs a dump for excess power or when the batteries are fully charged. A solar MPPT or PWM will not work.

I would never risk a battery bank to an un-regulated wind gen - or solar array.

[svPearlLee]

Midnite Solar has MPPT controllers that can be set to work with wind generators.

[Canibul]

You leave your boat, probably. We don't, not for more than a few hours. Our battery bank is NEVER fully charged. There are lights, fans, an Engel, the fridge compressor, a VHF running 24 hours a day. We have a constant DC load. Our problem is keeping the batts up at night or on cloudy days.

The wind generator doesn't put out enough juice to fry a battery in a few hours. Especially one with constant loads on it.

Why do you say a MPPT or PWM won't work? a volt is a volt. The solar varies too. The MPPT doesn't have a clue where those volts are coming from.

[mitiempo]

Originally Posted by Canibul

Why do you say a MPPT or PWM won't work? a volt is a volt. The solar varies too. The MPPT doesn't have a clue where those volts are coming from.

Same reason you cannot run your alternator output into your solar controller.

There may be some controllers designed to do this - Midnite Solar as mentioned above - but the rest are not suitable.

[Canibul]

Originally Posted by svPearlLee

Midnite Solar has MPPT controllers that can be set to work with wind generators.

Thanks for that info. I just wrote them to ask, but it appears from the site that their classic version is the one that supports wind mppt. $ 850. I can put a new reg in the Air-Ex and a new set of blades on it for that.

Still it gives me hope. I don't want to sink a lot into this old Air-X, as I have plans for a lot of new stuff coming down the pike. I like the idea of an MPPT I can use now for the wind and later for new solar.

[Canibul]

Originally Posted by mitiempo

Same reason you cannot run your alternator output into your solar controller.

.

I guess I am asking you specifically what that reason is.

[mitiempo]

Originally Posted by Canibul

I guess I am asking you specifically what that reason is.

I do not know the specific reason. You can see from this chart though that most controllers are not designed to control wind gens.
http://www.midnitesolar.com/pdfs/comparisonChart.pdf

Remember also that if you decide to run without a controller that the terminal voltage at the batteries will be much higher than desired.

[Xthewater]

If the wind generator controller is fried but power is still being produced it is likely AC which the MPPT can't regulate and you'll ruin the batteries. Wind gen controller typically rectifies the gen output to DC via diode bridge and regulates the output by shunting (controlled shorting) the power through resisters via electronic switching( op amp, transisters, zener diode, Hall affect or similar). The braking is done by shorting the output and magnetically locking the generator stator to the permanent magnet rotor.

An alternator does similar by rectifying the output to DC but regulates by controlling field voltage(excitation) via the 12v batteries, which is why if alternator output is disconnected from the batteries the alternator loses reference, goes full output and blows the regulator.

[Canibul]

Thanks for the explanation. Most of that actually makes sense to me. I'm surprised that I am reading AC voltage on my DVOM when it's set on the DC Volt settings, though.

[Maine Sail]

Originally Posted by Canibul

I guess I am asking you specifically what that reason is.

PWM regulation works on alternator regulators, battery chargers and solar because the pulse time can be varied to match the output current needed to both maintain yet not overshoot the voltage set point.

An alternator field can be PWM'd as can the power supply in a charger or a solar panel. Wind generators can not have have the load cut entirely or PWM'd at high SOC's or they can destroy themselves when the battery gets close to or full and the gen is spinning wildly.

Instead of PWM regulation for absorption wind gens use what is called ON/OFF regulation or shunt based regulation and brake (shorting) or use a dump load to slow or stop the blade when the batteries are decaying back down from the OFF voltage to the ON voltage.

MPPT is only useful in bulk and a wind gen can use MPPT but once it hits a regulation voltage it then needs to become an ON/OFF/BRAKE controller or have a dump feature during the OFF period. Most MPPT controllers simply become PWM once absorption voltage has been attained. Shunting or ON/OFF regulation is horrible at fully charging batteries and the last bit can take forever. This is why solar is far superior for the last few % than wind is. Wind is great in bulk, but not so much for finish charging, which is where solar wins...

A typical win gen controller will turn OFF at say 14.2V +/-, brake or slow the blade, and then not come back ON again until the battery voltage has decayed to 13.0V +/-. During the OFF time the blade is stopped or slowed drastically through shorting it or dumping it to a large load bank that slows the blade to a crawl.. If you used PWM the blade would be spinning like a banshee when the batteries neared full and this is NOT GOOD for a wind gen......

[Xthewater]

Originally Posted by Canibul

Thanks for the explanation. Most of that actually makes sense to me. I'm surprised that I am reading AC voltage on my DVOM when it's set on the DC Volt settings, though.

You would be seeing half the component of the AC sine wave on the DC function of the meter. Remember the polarity reverses with AC at the rate of 60 Hz.