Multiple wind turbines linked

[Cjjones]

Hi everyone, I am trying to connect 3 500 W wind turbines together and need some advice please. Currently I have all 3 set up running to their individual charge controllers and then need to connect them to 2 100AH batteries. Can I use a busbar to connect all 3 and then run the wires to charge the batteries or do I need additional components? Thank you very much for your help.

[Adriaan Kragten]

I assume that all three wind turbines are identical and have the same nominal voltage. I also assume that every wind turbine has a 3-phase PM-generator which is rectified. So the DC lines are connected to each other.

Even for identical wind turbines, the open voltage may differ because the wind speed may differ for each site. It might even be that two wind turbines are turning but that one has not yet started. If this is the case, no power of the two running ones will flow to the generator of the other one because the rectifier diodes prevent that the current is flowing backwards. So if you connect the three plus lines and the three min lines, you will get the average loaded voltage of the running ones. The loaded voltage depends on the nominal battery voltage and increases lightly with the current and with the charging state. But as the open voltage of every single wind turbine might be different, this means that the power generated by each wind turbine can be different too. But this is no problem as long as every wind turbine has the same nominal voltage.

To protect the battery against over charging, you need a battery charge controller plus dump load. The maximum power which the dump can dissipate must be a factor three higher than the maximum power of the dump load of a single wind turbine.

[SparWeb]

Without knowing what kind of charge controller you have, I'm going to start by saying that you could be in trouble by hooking up the WT's to the CC's.  There are some types of CC that will regulate a WT, and an awful lot that won't and lead your WT to a self-destruction.  Or maybe it's a package-deal controller that's supposed to be hooked up that way (but presumably there should be instructions in the box!).  So telling us what WT and what CC you are using to get a safe hook-up.

Are the 3 WT's giving out 3-phase or single phase AC, or DC?  That also matters in the hook-up of course because you would need rectifiers for the AC types.  If that's also in the package with the controller, wonderful, but I can't just assume it is.

Have you got a diversion load?  Depending on what kind of CC you got with your WT's, you may need one.

[kitestrings]

Welcome Cj,

I'll just add one other consideration to Spar & Adriaan's comments, just to say that 100AH is not a lot of storage.  Most small wind turbines are vastly over-rated.  Their "rated power" is often at a wind speed that is higher than all but a finite set of storms.  Still, if each unit was hitting 500w, you might see some 35 amps (assuming a 12V system) on each, or a little over 100A combined.  Your battery in those, albeit rare, conditions would only sustain that charge level for maybe a half-hour before the controllers would be starting to reduce the charge rate.  A portion of the available power soon needs to go somewhere other than the battery, and you're looking at a diversion/dump load to burn some of it off as suggested.

[Cjjones]

Thank you all very much for your help so far. To confirm, I need to place a dump load between my charge controllers and the batteries. My CC are FW12/24wind generator braking voltage 14.5V wind generator recover voltage 13.2V IP Protection IP67. I will try to add some pictures but it is not letting me for some reason. It was a package deal I purchased.

[SparWeb]

Hi CJ
We don't let new members post links or photos because the spammers love doing that.  You'll get to post links and photos yourself after you've contributed a few more times.

In the meantime, I'll try to make some educated guesses and post links for you when you give me enough information.  For example:
https://www.smallwindturbinegenerators.com/tags/fw12-24/

Is the right CC?

[Cjjones]

Yes thank you that is correct.

[SparWeb]

OK
Does it come with printed instructions?

Anyway judging by the product picture, you hook up the charge controller:
red and black - to the battery
green green green - to the wind turbine 3-phase AC

...and that's it.

I see no hook up for a dump load or any way for your controller to control one.
It does have 3 lights.  I can make some assumptions, and then guess for you what they mean... 

This thing doesn't come with an instruction manual, does it?!?
(oh, I asked that already, didn't I?)

[Cjjones]

Yes it did come with instructions and I hooked them all up according to the manual. I just wanted to make sure that if I connect all 3 + together and all 3 - together and then run 1 wire to the my batteries that it will be ok. I have had 2 of them running connected like that and dont see any issues yet but I wasnt able to find if that would cause a problem or not. I am getting a charge from them and dont seem to be having any issues but would like to double check .

[SparWeb]

These controllers look pretty cheap when compared to the "made in america" types that start at 150 bucks.  Your risk.
Since these CC's will probably quit on the day they gets rained on (I don't believe the IP67 claim) try to keep them indoors.  I have no idea if they also shed heat but presumably do have rectifiers but maybe also braking resistors.  Could get hot.

Normally you would connect one controller per wind turbine to the same battery.  Each CC will monitor battery voltage and adjust whatever it can on the WT accordingly.
You seem to be saying the same thing, but writing "then run 1 wire to my batteries" isn't crystal clear.  You mean that they CC's are mounted together, but pretty far from the batteries.  So you'd like to join the 3 CC positive wires together and run a single (heavier) positive cable down to the batteries.  Same for the negative.  Which would be 2 cables instead of 6.  That's fine, if I understood you correctly.

[Bruce S]

Being that I work around IP67 level equipment everyday and none of the pics available show enough to make a true determination, though the Amazon pics do  show that the bottom is correctly enclosed.
There are also certifications that gets issued. Their statement on their website of Salinity isn't correct either, IP67 is a statement only for fresh water.

Therefore I will stand with SparWeb on this one.

Cjjones; You own the equipment and know far more than we do as to how well it works around a wet environment.
It would be cool to have more about technical info about your setup ) And Pics !!

Cheers
Bruce S

[Cjjones]

I have all of the controllers and connections in a weatherproof box to help eliminate weather issues. Sorry I am lacking on my technical descriptions I am very new to this and some of the important details like connecting them all and then just running 2 cables to the batteries I didnt explain properly. Thank you for being able to interpret what I was asking. I have them all running now and they seem to be fine so I will just monitor them and see how they do.

[SparWeb]

You're welcome.  Always interested so please feel welcome to let us know how it works long-term.