TalkBaja.com » Baja Mexico Forums » Off-Grid / Solar, Wind or Generator?

OK, I have been buying and accumulating solar panels and equipment as I gear up to start to put our off-grid system together. A customer of mine acquired a new, still in the box wind turbine that came as part of a lot sale of merchandise he purchased. He was kind enough to give it to me in appreciation for past work I have done for him but now I find myself rethinking my system design.

I have a lot of questions about hooking up the system with solar and wind combined and was wondering if anybody here has actually tried it? For starters, do I use the same controller to feed the batteries or will the wind turbine need to be on its own regulator/controller?

Hey Baja Gringo,

I'll look through my accumulation of wind information, but I'm fairly certain the wind turbine needs it's own controller and it may even need a controller specific to the turbine. I may not get back for a few days though. Our internet is going to go offline as they're switching to a new satellite and I have to re-align the dish.

No problem Woo - I was hoping you would see my question. Get back to me when you have a chance. And I WILL have more questions...



Gracias!

Here is the contact info for the guy who installed our solar systems both elec & hot water. He's very informed on these matters 25+ yr in the industry.
Rolf
rdrager@ecoyeco.com
664 227 7107

I think most turbines are at 24v. I have been wrong often, though. If you have a 24v system I can't imagine why you couldn't use the same controller as long as it can handle the amperage.
If that is not the case then I would consider the purchase of a step down or up transformer that might make it compatible. I think a transformer might be cheaper than a separate controller. However, you step down you increase amps.
Call Tom at http://thesolarbiz.com/ , he will talk your ear off and spend as much time as you need to set you straight.
Good luck and keep us posted so I can see how many ways I am wrong. It is way easier for me to learn by other people's mistakes.

Thanks Rolf & Soulpatch. Actually the wind turbine is 12 volt output. I know that some folks think they are not worth the investment but since the price was free and the unit was built for marine use, I figured I would be a fool not to give it a try. During construction I embedded sections of 2" pipe vertically into the back two corners of the house wall thinking I would use them for antennas, disks or something. The wind turbine should mount just fine on 1.5" pipe that we can weld inside one of the 2" pipes and give the turbine good height (~35') and support.

We do get a fair amount of wind out here just about every day of the year and I like the idea of something adding a little charge to our batteries while we sleep. I will try giving these guys a call and report back.

Thanks again!

I've read here and there that's it's not a great idea to have a turbine attached to your home; way too much noise/vibration transmission.

Maybe over the guest bedroom; keep those pesky stays a reasonable length.

I thought I remembered it was more difficult than just hooking a wind turbine up to a charge controller. I found this article in my mass of information. Basically the wind turbine needs to be under load constantly, solar panels do not.

When using solar panels only, the charge controller basically shuts of the solar panels when the batteries are full. You can't do that with a wind turbine. With a wind turbine you need a set up that shunts the load to another location or "dumps" it while keeping a load on the turbine (after the batteries are full) to keep the blades from free spinning. I'm not really sure just how it works though as I've never done much more than read a little about it.

Here's the article (I think I copied it from the wind-sun.com forum):


In general--Solar and Wind use two different types of regulation. (note: all generalizations are wrong--including this one).

Solar panels can be turned on and off without any damage. So the solar charge controllers are connected between the panels and the battery bank (not including fuses/breakers, which is a whole issue itself):

solar panels -> charge controller -> battery bank

Wind turbines typically require a load 100% of the time, or if you Turn off their power (open a switch) -- two things happen.
1. output voltage goes way up--could damage electrical components
2. no-load on wind turbine allows strong winds to cause turbine to over-speed and self destruct

#1 is possible with some wind turbines with internal electronics... #2 is a problem for all horizontal axis wind turbines (HAWT)--No load on the turbine will cause the turbine to over-speed and toss blades, ruin bearings, collapse tower, etc.

So--the typical wind turbine is connected to the load (battery bank) 100% of the time. As the wind increases, the charging current / power keeps the blades spinning within the safe range.

But, in times of high wind and light loads, the battery can overcharge. So, a "shunt" controller connects to the battery and turns on when the battery is full--dumping the excess energy to an electric heater of some sort:

Wind turbine -> battery bank -> shunt regulator -> resistor bank

Note that in this case, if the shunt regulator or resistor bank fails--you can have dangerous over charging of the battery bank... So, the US national electrical code (NEC) requires that two independent shunt regulators/load banks be used -- in case one fails, the other will still function correctly. If your battery bank is not in your home/place where a battery failure can cause problems--you could pass on the second shunt regulator.

Note that there is a common method of "turning off" the output of a wind turbine... Basically, disconnect from the battery bank (switch or blocking diode) then short the +/- output of the turbine. Since Power=Voltage*Current where voltage equals Zero Volts, there is no heat/load bank required to limit the speed of the turbine (used for maintenance or in stormy weather).

However, there is heat generated when a wind turbine is shorted--it is generated in the windings of the wind turbine's alternator/generator--this has been known to cause overheating/failure inside the wind turbine. So, as always, review the manual for proper setup of the turbine's electrical system.

Now--to confuse things even more--People are designing MPPT (maximum power point tracking) charge controllers for wind turbines that connect like a solar charge controller does (between wind turbine and battery bank) to increase the power generations from the turbine--I have not seen the details of the setup yet--so I do not know how they handle the excess energy (direct attached loads, short the wind turbine output which slows a turbine way down, or whatever)....

So--it goes back to reading the manual for the wind turbine/charge controller setup you have. Generic answers are helpful to learn the terms and the various ways of setting things up--but may not apply directly to your particular brand/model/setup.

I hope I made things clearer rather than more confusing...

-Bill
__________________

Maybe you could design a "shunt regulator -> resistor bank" that would warm a portion of your pila water...

Yes, the wind turbine will need to have a dump load available and I have found several examples already of how that can be configured. What I am finding out is that their are hybrid controllers built to handle solar and wind at the same time but they don't seem to have all the features of some of the better controllers designed for just solar or just wind.

And yes, the turbine will be located over the back guest bedroom. Although the specs say it is rated at only 55 dB...

Thanks Mr. Wooooooo.
I remember that now. Sheesh, put down the books for a few months and my cheese like brain lets everything leak out.
Sounds like a perfect reason for a transfer switch to resistive load of some sort.....warm water storage?
I would never have to worry about overcharging my batteries when I am down south.....my usage far exceeds my ability to charge.

Originally Posted by BajaGringo

And yes, the turbine will be located over the back guest bedroom. Although the specs say it is rated at only 55 dB...

Now that's a Great Idea to keep guests from staying too long!!!!

Originally Posted by soulpatch

Thanks Mr. Wooooooo.
I remember that now. Sheesh, put down the books for a few months and my cheese like brain lets everything leak out.
.

There's too much to remember about solar. I have a ton of info, but finding it's my main problem.

Gringo, please keep us updated, I'd like to hear how your wind turbine works out. If my soon to be installed upgrades aren't enough power, if your's works out, I may look into getting a windmill. You can be the guinea pig

We've had a lot of wind around 20 mph lately, continuing into the early evening. That's a lot of extra power, but I'm still a little leery about how much noise they make, although I haven't been around any of the newer models.

The next door neighbor to a friend of mine north of LA has two on his roof. They use the same style blades as the one I am getting and he tells me they never have been a nuisance.

This is the same model as mine so you have an idea of its size / what it looks like:

I really like some of the products I have found at a company called Coleman Air. The attached link will show you the components I have purchased except for the grid-tie arrangement.

http://www.colemanair.us/vp_asp/Scri...igPicture2.htm

Originally Posted by BajaGringo

I really like some of the products I have found at a company called Coleman Air. The attached link will show you the components I have purchased except for the grid-tie arrangement.

http://www.colemanair.us/vp_asp/Scri...igPicture2.htm

That looks like a great system. I bet you can't wait to get it up and running

I started looking through the info in their website. Lots of info and good products. Wish I'd have seen it earlier.

I originally found them on eBay. If you order anything from them it is slightly cheaper from their own website (saving eBay seller fees) and they do accept PayPal on their own site as well. I have emailed them a few times and they are always back quick with an answer. Nice folks.

Yes, I am really looking forward to getting the system up and off (or less time on) the generator. As soon as I get the batteries bought and down here we will begin. I have been using the guest bathroom (that is not yet finished) as a storage room for all the gear and boxes for the system. I know that Cristina will be glad to see it cleared out too.

So here is my basic 12/24vdc - 120vac power generation layout...

I've never seen a system that splits the load from day/evening. Are the battery banks completely isolated from each other?