24volt wind generator-rectifier between generator & battery?

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24volt wind generator-rectifier between generator & battery?

Postby bergy » Mon Oct 31, 2016 9:18 pm

Hi, I am new to all of this.
I recently installed 3 * 250 watt panels coupled to a 2.4 kw off grid inverter and it is working a treat.
I decided to add a 24volt 1500 watt 60 amp with max volt output dc 36 volts wind generator to add more imput to my batteries.
I have recently received my generator and are in the process of adding it to my system.
On doing some research i have discovered that i can't connect the wind power into the inverter but instead direct into the batteries.Then i purchased a wind controller and power dump (water heater )
I was concerned at the wiring diagram for the controller which shows the wind power going direct into the batteries before going to the relay for the overcharge dump.
I then discovered that some recommend the inclusion of a rectifier before the controller.
My question is ,Is this the correct process, If yes where do i source a 24 volt rectifier
Is there any diagram i can research to confrm the correct wiring to avoid a meltdown.
Thanks in anticipation
Brian
Last edited by Gordon-Loomberah on Thu Nov 03, 2016 10:49 am, edited 1 time in total.
Reason: edited subject to fit in the available space
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Re: 24volt wind generator rectifier between generator and ba

Postby Gordon-Loomberah » Mon Oct 31, 2016 9:36 pm

Hi Brian, a few questions will help understand your situation a bit better:
what capacity is your 24V battery?
What are you using as a charge controller for the solar panels?
What brand and model is the wind generator?

Typically a wind generator would output 3phase AC, and this would be rectified in the controller. You can buy 3 phase rectifers reasonably inexpensively online (or build your own from 6 diodes) if your controller needs a DC input, rather than 3phase AC. You will need a significant heat sink on it though.

Do you live in a particularly windy location? Most people don't, and for the same expenditure, will get a lot more energy from solar panels than they will from a wind generator. Even in windy locations, it ideally needs to be 10m or more above any surrounding obstacles out to 100m distance.

If the water heating resistor is on the output ie, DC side of the controller, it doesn't really matter which side of the battery it is connected to. It does need sufficiently large sized cables though, and as short as reasonably possible, as 60A can rapidly overheat undersized cabling.
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Re: 24volt wind generator rectifier between generator and ba

Postby bergy » Tue Nov 01, 2016 8:07 am

Good morning Gordon,
Thank you for responding to my question.
In response;
My batteries are 12v 180 amp hour each wired as 24 volt glass mat deep cycle.
On the solar side I have a 2.4 kw Mpp solar inverter. ( which is working very well,running approx half of my house )
The wind generator is a 2 kw Eolo vertical tower generator rated at 1.5 kw 24 volt output current 60 amp max voltage 36v dc.
We live in a particularly windy area on top of a hill in the Adelaide Hills.We have the tower at 8 metres and uniterupted area around the tower.
I have a 700watt heater as heat sink.
Do i need a rectifier between the tower and the battery ? ?
Thank you for your interest
Brian
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Re: 24volt wind generator rectifier between generator and ba

Postby Gordon-Loomberah » Tue Nov 01, 2016 8:54 am

Are your panels connected directly to the battery, or to the MPP inverter? If connected to the inverter, I assume it has a built-in solar charge controller?

How many wires come out of the wind turbine? If 3, and there are 3 input terminals on the controller, and 2 output, then the rectifier is in the controller, which is usual practice.

If your wind generator actually produces its rated output, it could be a bit much current for your 180AH battery.
How sophisticated is your controller? Does it have settings for bulk, absorb and float? If it just regulates to a single fixed voltage, you need to make sure it is the float voltage for your battery, otherwise the battery could be damaged.

If your battery is fully charged and the wind generator is putting out 1500W on a windy August afternoon, you'll need to be around to make sure you are using the extra 800W output which isn't absorbed by the 700W resistor, because an uncontrolled ~30A going into 180AH battery could quickly damage it.
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Re: 24volt wind generator rectifier between generator and ba

Postby bergy » Tue Nov 01, 2016 9:14 am

Thanks,
My solar panels connect to the inverter then the batteries.
There are 2 wires coming from the wind generator (they seem smaller than i would expect )
The controller is a Eazy_4 u3 with a solonoid.
If i need more dump capacity i could add another heater or more.
I would consider more batteries as needed but at this point i just want to get the bugs sorted and get it working.
It would have been better in hindsight to add more panels and not enter the world of wind power.I did it out of interest but never anticipated the issues.
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Re: 24volt wind generator rectifier between generator and ba

Postby Gordon-Loomberah » Tue Nov 01, 2016 12:39 pm

OK, only 2 wires from the wind generator suggests it is internally rectified. You should be able to test this for yourself with a multimeter if it is a permanent magnet alternator. It's slightly more complicated if you have to energise a field winding, but still doable. Set it to DC volts and spin the alternator by hand, you should see a DC voltage across the terminals. Reverse the leads and you should see negative voltage (assuming you have a digital MM, and you should get one if you don't already have one- they are very handy).
Undersized output cables is not uncommon on cheap Chinese equipment, what size is the conductor?

What charging voltage set points do you have on the solar?

What does the user manual for the wind generator or controller say about the charging voltage set points? I can't say I have ever heard of Eazy_4u3 as a brand.
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Re: 24volt wind generator rectifier between generator and ba

Postby bergy » Tue Nov 01, 2016 1:36 pm

Thanks,
I am currently unable to do the test as the unit is on it's side on the ground ready for a couple of strong lads to hoist it up.I have this morning modified the height of the tower from 6m to 4m off the ground following your concerns of over production of power.I have also made up a friction brake to apply pressure to the hub to reduce the rpm in time of high wind.
Your question re size of conductor is lost on me ( sorry but i have no idea what the conductor is ! )
On the solar i have my low voltage set at 24 volts and high set to 28.8 volt ( the solar side of things is working very well, the batteries are full by about 10 am even under cloudy conditions.) We are running our tv 160 watts,water pump 850 watts microwave & fridge.1200 watts and most mornings the batteries are almost at 24 volts & that is why i thought wind overnight might put a bit in.Probably more battery storage would have been a better option. (But batteries are the super expensive part of this exercise.)
The controller set points are unknown .I have not yet hooked it up and the instructions tell me nothing. (I tried to attach the controller instructions but it was over size according to the site and i can't shrink.
The controller has a Sea 440 regulator ( if that means anything to you )
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Re: 24volt wind generator rectifier between generator and ba

Postby Gordon-Loomberah » Tue Nov 01, 2016 2:30 pm

ok re the test, the information should be in the user manual anyway. Loweringthe tower could result in more stress on the turbine, due to greater air turbulence near the ground, but vertical axis turbines aren't as badly affected as horizontal. It should be ok, assuming the contruction quality is good.
Re the friction brake, it is probably best to use it to stop the turbine in very high winds, as it is likely to get very hot in sustained high wind.
By conductor, I was referring to the Copper, which is surrounded by insulation, rather than the overall diameter of wire including insulation. If you can measure the diameter, cross sectional area is easily calculated. I would expect it should be 6mm^2 or more in X-sectional area.

When you say low and high voltage of 24 and 28.8V respectively, do you mean for low and high voltage disconnect? What are your absorb and float voltage set at, and absorb time or end amps?

24V in the morning with no load suggests you are discharging the battery quite deeply, which will result in a much shorter life than you might expect.

What format is the controller file in?
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Re: 24volt wind generator rectifier between generator and ba

Postby bergy » Tue Nov 01, 2016 4:32 pm

Thank you for your perseverance Gordon,
Re friction brake stopping the turbine completely may be a problem in high winds.I will try to come up with another method.
Conductor, ok size of wire.....yes about 6mm dia.no more.could be 5mm.
24volt to 28.8 volt. Below 24 it changes over to mains power automatically over 28.8 it goes to dump mode.
No idea what the absorption,float or end amps refers to.Cant findany reference on screen.
24volt in morning is just above bypass mode.I agree it is too low.It is under load at that time ,probably about 15% load.
The file I tried to send was a email file i tried to attach
Brian
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Re: 24volt wind generator rectifier between generator and ba

Postby Gordon-Loomberah » Tue Nov 01, 2016 4:52 pm

You can include image files of various types, but not pdfs, or other types of files (other than pasting in .txt etc) as they can't be displayed correctly by the forum software.

hmm, I'm wondering if you have unregulated solar charging going on there, since all chargers/regulators should have set absorb and float voltages. That is generally not good for long battery life, unless you can manually regulate with pointing panels away from the sun and adding or removing electrical loads (I used to do that myself years ago, but you need to be around all the time, and monitoring battery voltage).

5-6mm diameter Copper could be 25mm^2, which is reasonably hefty and is more than large enough, although I am surprised that you thought it was smaller than expected! Are you definitely talking about only the wire part in the middle, and not including insulation?
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