Author Topic: 10' Turbine With Off-grid System (Read 3070 times)

arwenvaughan · « **on:** July 15, 2009, 04:40:12 PM »

I am almost finished building one of the 10 foot Homebrew Wind Power turbines and will hopefully have it flying at a friends house. The house is one of these off-grid "earthship" homes down in Taos, NM. I am trying to understand his existing electrical setup so I can begin planning how to wire the wind turbine into the system. I am trying to get started with these pictures so I don't have to drive 5 hours to take a closer look at the system in person.

I included a picture of the solar panels, batteries, and the charge controller below. The system appears to be setup with all the right AC and DC disconnects, circuit brakers, etc. I am thinking that those are 6 volt batteries so that makes it a 12 volt system (5 strings of 2 batteries in series?), right? Also, does that look like it is marked as the trace C60? If so how do you know if it is set for 12 or 24 volts?

I am assuming that you would need another charge controller specifically for the wind turbine so I can dump load, right? What equipment/venders would you recommend using for tapping the 10 foot wind turbine into this system?

Thanks in advance for any comments!!

SparWeb · « **Reply #1 on:** July 15, 2009, 12:15:13 PM »

Don't you love it when that green LED on the Trace stays on solid?

It's a happy light, and in my setup I don't see it like that often enough.

That's probably a Trace C60, with the label punched beside the C60 number (I know, why can't they just print 3 labels and put the right one on at the factory...)

To find out how it's set up, you have to open the cover (this is one piece of equipment that tells you the warranty is void if you DON'T open the cover).

The setting for 12v/24v is a jumper inside, on the right. There's another jumper that must be moved if it goes from controlling a solar cell to a windmill.

You can download the whole installation manual from the Xantrex website. It shouldn't be too hard to find but it you have trouble, just ask, I'll dig up the link.

Another C60 will be a suitable charge controller for a 10' windmill, though users here seem to have more success with Outback's charge controller, because it's more responsive to surges of current in wind gusts.

Something really important to bear in mind, since you mentioned New Mexico (I assume that is "NM") is that at high altitude, your wind turbine collects less power because the air is significantly less dense. It's a factor you can ignore in a lot of places, but I just happen to know NM has some very high ground levels.

ghurd · « **Reply #2 on:** July 15, 2009, 12:48:10 PM »

The MorningStar TS-60 is faster to respond too.

The C60 is "kind of obsolete" in a dump / diversion mode area.

G-

arwenvaughan · « **Reply #3 on:** July 15, 2009, 02:54:01 PM »

Thank you for the comments SparWeb and Ghurd! I have a couple of follow ups questions if you don't mind.

I'll have my friend open up the Trace and look for the jumper. So it is either 12 or 24 volts from the panels to the charge controller. Would you say for sure that this is a 12 volt battery bank then? Damn, I was hoping he had a higher voltage battery bank.

The Homebrew book says that a 12 volt system would need a controller rated at 130 amps for the 10 footer wired for 12 volts? The MorningStar TS-60 is rated to 60 amps right? What am I missing here? Would I really need two controllers wired in parallel for a 12 volt system?!? Wow this could get expensive.

arwenvaughan · « **Reply #4 on:** July 15, 2009, 04:41:06 PM »

Good point about the elevation...I'll find out how high he is. Besides that I think it is a pretty good wind site. There are no trees and the houses are all dug into the ground so there are no obstructions. I am planning on doing a pretty short tower because of this and to keep cost down. A lot of other people are successfully using wind turbines in the area as well.

wpowokal · « **Reply #5 on:** July 15, 2009, 05:31:45 PM »

Appears to me to be a 24V system, why can this person not tell you his system voltage, perhaps you need to ask that question differently.

It is not a particularly large set up so for good winds an adequate dump load will be essential.

allan down under

ghurd · « **Reply #6 on:** July 15, 2009, 05:38:22 PM »

Yes. It is set up for 12V.

The batteries are not set up very well.

There is more info about connecting the batteries together here,

http://www.fieldlines.com/story/2009/7/6/8479/47114

The PVs look substantial. I suggest you look into MPPT for solar.

The 130A for 12V is always a problem.

The controller is last in line.

First is cost of the wire on a large system with a long run.

Second is efficiency for a system that needs that kind of charging amps.

Third is the windmill stator and the heat it must endure.

There are ways to get around the max amp limits of some controllers.

The cost is going to be up there.

It is not uncommon for the dump load to cost more than the controller.

G-

arwenvaughan · « **Reply #7 on:** July 15, 2009, 07:12:01 PM »

Well, he can not tell me the system voltage because it has worked so well since he bought the place. He hasn't had to learn anything about the electrical system yet.

The house has 12 volt lights and and inverter, which makes me think that the batteries are 6 volt...making the entire battery bank 12 volts. I guess you could be right though. I'll have to have my friend take a closer look at the batteries so we can figure it out for sure. He probably needs someone to walk him through the entire electrical system at some point.

I will have to take a look at dump loads next. Thanks for the post.

jimjjnn · « **Reply #8 on:** July 16, 2009, 07:49:49 AM »

The batterues look like they are in need of maintenance.

Some of the conhnections have green corrosion on them which is not good

SparWeb · « **Reply #9 on:** July 16, 2009, 12:41:07 PM »

The batteries look either like Trojan L-16's or T-105's, either of which would be 6v, so I'm voting for "it's a 12v system".

Stepping back from the bits and pieces... You describe your friend as a "hands-off" kind of person, or maybe they don't live there year-round. Are you sure that a windmill, which requires more attention than a row of solar panels, is appropriate? No disrespect is meant, but it is a valid question. My wife doesn't know much about my RE system, but I have written out instructions that she can follow if something goes wrong when I'm not around.

Windmills work much much better when configured for higher voltages. You will spend a lot of money providing for high-current charge control and dump-load resistors, which could better be spent on a higher-quality inverter, for example.

Expandability can be a big problem when looking at these systems. Either there is one component that bottle-necks the rest of the equipment, or the way the old stuff was put in makes adding new stuff more complicated.

I personally like these kinds of challenges, but I know that most people don't appreciate it.

Ungrounded Lightning Rod · « **Reply #10 on:** July 16, 2009, 09:13:45 PM »

Ask him if there are three or six wells under the battery caps.

arwenvaughan · « **Reply #11 on:** July 16, 2009, 09:32:34 PM »

Yeah, you're right it is a valid question. I may not be up for that much of a challenge since the "earthship" is in fact a second home, he's hands off, and it is a 12 volt system. It just seemed like a good place to test it out for a while since it is off grid and wouldn't need a very expensive tower.

I won't have a place to fly it until I buy some land in the mountains. I've built this 10 footer as a learning experience mostly but also to use it down the road. I live in the city (at least for now) so I can't fly it here. Anyone in the Denver area want to let me fly my turbine on their land so I can test it out for a while ? Anyone need a little free electricity? No seriously.

SparWeb · « **Reply #12 on:** July 17, 2009, 09:28:43 AM »

Don't be discouraged. It's always possible to make one stator for 12v, then when you want it for your own system, make another stator for 24v or 48v. But in the meantime, you'll have to consider yourself "in charge" of the windmill even though it's on somebody else's property. The learning experience from setting it up and running it there will be rewarded when you get to re-install it on your future country home.

ghurd · « **Reply #13 on:** July 17, 2009, 10:26:21 AM »

I hope he has been watering those batteries.

Those wally-world 99 cent red&green felt battery washers work wonders, as a preventative.

G-

Ungrounded Lightning Rod · « **Reply #14 on:** July 17, 2009, 12:21:12 PM »

I notice several PVC jugs off one end of the batteries. I suspect they're distilled water and he has been doing at least that much maintenance.

(I also notice both + and - are connected at one end of the string. Oops. Hope his load is small.)

arwenvaughan · « **Reply #15 on:** July 17, 2009, 03:56:53 PM »

Yeah, I have seen him water the batteries

He does a good job keeping it running. I think this is a testament to how well a RE system can run for years without too much effort.

arwenvaughan · « **Reply #16 on:** July 17, 2009, 04:00:18 PM »

"(I also notice both + and - are connected at one end of the string. Oops. Hope his load is small.)"

What is this? Can you explain...I am just learning here so I'm not sure what the problem is.

wpowokal · « **Reply #17 on:** July 18, 2009, 02:36:09 AM »

It is simply equalizing the current draw from each battery, to this end the leads from each battery should be equal. In this case the battery closest to the inverter will in theory take more of the load, but like life very few things are perfect.

allan down under

arwenvaughan · « **Reply #18 on:** July 18, 2009, 12:11:55 PM »

Ok, I see that makes sense. I'll pass that on to him.

Thanks!!

Ungrounded Lightning Rod · « **Reply #19 on:** July 20, 2009, 01:20:34 PM »

Easy almost-fix is to move one of the power takeoffs to the other end of the string, kiddy-corner style (if you have enough cable). That's not perfect, but with five cells it has only 1/5 the imbalance. (The cells toward the middle are loafing, but the middle one is only loafing by a fifth as much as the end one in the existing arrangement.)

Your currents are probably not high enough to make it worth building a bunch of longer (and costly) cables to do an exact balance. Especially since this thing has been running adequately for a while. But if you're adding a wind generator your currents will be going up. So getting a reasonable balance and not overstressing the connection-end battery may become more of an issue.

arwenvaughan · « **Reply #20 on:** July 21, 2009, 09:56:45 AM »

Thanks Underground Lightning Rod. One more question. What is the ideal way to hook these batteries up. I mean, is the idea to have the battery terminals of each string connected by the same length of wire? I don't understand how you would do this really without using a ton of wire. What about hooking the positive and negative leads to the battery terminals of the middle string of batteries. Or is this just as bad as the way it already is?

Ungrounded Lightning Rod · « **Reply #21 on:** July 21, 2009, 07:14:02 PM »

A) Each battery has a separate cable to a + and a - terminal block connection. (The "terminal block connection"s may be a + post on one battery and a - on another.) The sum of the lengths of the + and - cables on each of the batteries is the same, though each battery may have, say, a long + and short - cable or vice-versa. (The "terminal post" batteries have only one cable with the total standard length, if you do it that way.) All cables, of course, are the same wire gauge.

B) With a kiddie-corner configuration all the jumpers are the same length. But as they get closer to the battery that has the feed terminal they get thicker, or are doubled/tripled/etc. up. Farthest battery has one jumper, next hop is double-thick or two jumpers, third hop is triple thick or three jumpers, etc.

With a charge/discharge rate of 100 amps or more I'd definitely get away from the existing totem-pole setup. I'd certainly go at least to the kiddie-corner and would consider going to a full-blown balanced rig, or approximating it by running an extra jumper from the fed posts on the end batteries to the middle battery.

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Author Topic: 10' Turbine With Off-grid System (Read 3070 times)