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

Ron
just gave your diagram a quick look and the only thing I noticed is that you have a transfer switch between the inverter and the main breaker panel. Depending on which inverter you are using, most of the newer inverters have built in transfer switches. They automatically detect generator power and let that power pass through to the main breaker panel. If you haven't bought it yet, you may not have to. Might save you some money.

Great info from Big Woo about grounding, thanks for that. I need to go through my system again and make sure things are up to par.

Originally Posted by rplarry

Ron
just gave your diagram a quick look and the only thing I noticed is that you have a transfer switch between the inverter and the main breaker panel. Depending on which inverter you are using, most of the newer inverters have built in transfer switches. They automatically detect generator power and let that power pass through to the main breaker panel. If you haven't bought it yet, you may not have to. Might save you some money.

Mine does Larry but I have this inherent distrust of such things working correctly. Too many of those neat devices like automatic switches have caused me headaches over the years. The havoc such a failure would wreak is a risk I would rather not chance. I was able to pick up a brand new, very nice Reliance transfer switch for a song on eBay (<$50).

Something I just noticed that I need to add to the diagram. The generator will also be running a 24vDC / 20 amp charger that will feed my batteries when fired up...

Really great post Wooo and it comes at the perfect time as I was in the middle of sorting out the grounding issues before continuing. Some comments...

--System ground at least 6 gauge wire tying all the chassis components together. Some say each panel should have a ground lug. I talked to an engineer that said that's overkill and grounding to the frame of the panel mount is fine.
Do you run your panels ground through the ground bar in your combiner box? Interesting discussion on NOT doing that here, based on the threat of lightening:

From Wind-Sun.com: A question about lightning...

--Neutral, ground, and system (safety ground) bonded at only one location, preferably the main breaker panel.
Are you saying you run all your grounds to the main panel???

--Battery negative does not have to be bonded to neutral and system ground, but if you do, it cuts down on any radio interference the inverter may produce.
I had read elsewhere that connecting the battery negative to the system ground was a big no no???

--Check to make sure neutral and ground are NOT bonded together in the generator.
They are not

--Do not run the system ground for the generator to a separate ground rod. This can create a ground loop that could overheat the windings in the generator.
Chava told me about that one

--Generator system ground should be tied back to the main ground buss.
I did that (based on Chava's suggestion)

--Make sure you only have one point where the system is grounded to earth. I'm not sure if that's the right terminology, but you should NOT have separate multiple, earth ground points.
So it's OK to have AC and DC share a ground?

--If you can, locate the ground rod in a garden area that gets watered regularly ( I don't, I plan to move it). Dry desert earth doesn't conduct very well or make a good ground.
A friend suggested placing it right by the outside faucet you use the most. Make a drain area filled with small pebbles/beach rock under the faucet to invite all the runoff to soak in, heading straight down. He also gave me a couple of tricks to help sink the ground rod further down.

--I'm not sure if lightning is an issue where you are, but if it is, (even occasionally) you should have lightning protection in:

1. Combiner box
2. Something in the wind generator, but I don't know what as I'm not familiar with those, and I would imagine in the wind turbine rectifier
3. Charge controller
4. Inverter
5. Input from generator
6. Main AC panel and any sub panels

Haven't seen any lightning here yet but I was thinking protection on the wind turbine at the very least. Refer to above mentioned thread on lightening and grounding. A lot of folks don't think it is a very good idea to protect your system by sending a lightning strike down your conduit into your system where it may very well fry everything. It appears that many have opted for a separate conduit away form the system wiring and keeping it outside the house.

Man... this thread is going to be one hell of a reference for anyone doing this... great work.. thanks...

Originally Posted by BajaGringo

Well if you are even considering living off grid you'd better learn fast!!!

LOL -- I'll have to hire a watchman who doubles as a solar power handyman.

This has been a fascinating process for me and I have learned so much along the way. I had a basic understanding of off grid living before starting this endeavor but there is soooooo much to learn if you want to do it right and get the most out of your system.

Another interesting side to this is that there is not one right answer for everybody. Your location, budget, power needs. and weather will greatly affect what will ultimately be the right system for you.

Many have told me I was foolish for trying to incorporate a wind turbine into my system, based on others experience and hearsay. I have been testing the turbine for awhile now and I can tell you that it will greatly enhance our system and go a long way to keep my batteries SOC above 80% at all times. But that is here where I live - not everybody gets as much, constant wind as we do. I eas also really pleased to find out they are not these noisy monsters some tried to tell me. You can barely hear the thing running when outdoors and you can not hear it at all inside the house.

Having taken the time to really research wind turbine technology I have learned where many have made mistakes in terms of turbine size, blade style, placement and system control.

I promise to post a full report on that once the final system is up and operating...

Originally Posted by BajaGringo

Mine does Larry but I have this inherent distrust of such things working correctly. Too many of those neat devices like automatic switches have caused me headaches over the years. The havoc such a failure would wreak is a risk I would rather not chance. I was able to pick up a brand new, very nice Reliance transfer switch for a song on eBay (<$50).

Something I just noticed that I need to add to the diagram. The generator will also be running a 24vDC / 20 amp charger that will feed my batteries when fired up...

Well, I can cetainly understand your reluctance to trust all this stuff to work properly, thats one of the reasons I went with 2 inverters, if one fails I have a backup. One disadvantage to a manual transfer switch that I found on one install I did was that when you switch from inverter to generator or vice-vrsa, power is interrupted and you will lose power to alot of your devices, directv recievers will reset, digital clocks go to 12:00, and desk top computers really don't like it, Satellite modems reset, etc.
Just curious, what inverter did you get for your system?
I'll also be intersted in how your wind generator holds up, that is something I don't have any experience with. I try to stay away from rotating machinery as much as possible. I always figured that if it rotates its gonna break. Over here on the SoC side there is lots of sun so having solar only is doable. I imagine on your side you get a fair amount of overcast days which would make solar a little less reliable,
Larry

I have a 24vDC / 3000 watt pure sine wave inverter and I am shopping for a backup. Like you, I am thinking that it will eventually fail so I want to have one ready just in case. I was even thinking about setting up the system to work off another, smaller 600-1000 watt inverter that could be switched to at night. I have since decided to nix that idea since the wind turbine is working so well and should easily overcome any battery drain from night time outside lighting.

In the couple of months we have been on the system haven't had to switch to the generator yet. I don't foresee that will be a regular occurrence. I don't have much of a problem in case we do as I use a laptop computer and my digital clock in the bedroom has a built in battery backup. The satTV will reset but our SKY system comes back up a lot faster than the DirecTV we used to use. The internet comes back almost instantaneously so I don't think the manual transfer should be too much of an issue.

The wind here is constant and the output form the turbine is very welcome on overcast days. It will eventually break down I suppose - I am hoping to get at least a few years out of it. I have gone to some effort to build a system that makes it easy to bring the turbine down in case we have any problems.

I am keeping my fingers crossed that doesn't happen any time soon...

"I have a 24vDC / 3000 watt pure sine wave inverter and I am shopping for a backup"

But which 3000 watt inverter did you buy? Outback, Xantrex, Midnite solar? Some of them can be "stacked" to allow an automatic back-up which in effect gives you an "almost" uninterruptable power supply.

Sorry Larry - the brand is SineTech and the model is a PM-3000H-24. Attached is some info on the unit. I don't believe they are stackable...

Originally Posted by BajaGringo

Really great post Wooo and it comes at the perfect time as I was in the middle of sorting out the grounding issues before continuing. Some comments...

--System ground at least 6 gauge wire tying all the chassis components together. Some say each panel should have a ground lug. I talked to an engineer that said that's overkill and grounding to the frame of the panel mount is fine.
Do you run your panels ground through the ground bar in your combiner box? Interesting discussion on NOT doing that here, based on the threat of lightening:
Yes...Solar panels to ground lug in combiner box, to lug in charge controller, to buss in main panel, then the buss is connected to the ground rod


From Wind-Sun.com: A question about lightning...

--Neutral, ground, and system (safety ground) bonded at only one location, preferably the main breaker panel.
Are you saying you run all your grounds to the main panel???
I have a large main panel that houses the main system (safety) ground buss. It also houses AC in from the generator, generator bypass and AC out. All system ground runs terminate there. I'll try to post a picture later.

I have three solar arrays hooked up to three different charge controllers. The system grounds for each array terminate at the system ground buss in the main panel, as well as the system ground wires from the inverters, generator input, and any system ground wires that run back from other AC or DC sub-panels. That is also where I have neutral and ground bonded, and it is the ONLY place where they are bonded. The main system ground buss then runs directly to the ground rod. I have no other wire runs that connect to the ground rod


--Battery negative does not have to be bonded to neutral and system ground, but if you do, it cuts down on any radio interference the inverter may produce.
I had read elsewhere that connecting the battery negative to the system ground was a big no no???

I just spoke to the engineer again. He thought I had a 48V system. NEC requires batt - and system ground to be bonded in systems over 48v. Below that voltage he doesn't recommend it. He says he's not sure he likes them connected in systems over 48V either, but in the U.S. it's required. I never connected mine. My battery - is not connected to system ground yet and I think I'll keep it that way. He said connecting them increases the chance for a lightning strike. Battery ground should float free in systems under 48 volts

--Check to make sure neutral and ground are NOT bonded together in the generator.
They are not




--Do not run the system ground for the generator to a separate ground rod. This can create a ground loop that could overheat the windings in the generator.
Chava told me about that one




--Generator system ground should be tied back to the main ground buss.
I did that (based on Chava's suggestion)



--Make sure you only have one point where the system is grounded to earth. I'm not sure if that's the right terminology, but you should NOT have separate multiple, earth ground points.
So it's OK to have AC and DC share a ground?

As far as I know...Yes. I have all my AC and DC system (safety) grounds tied together in one buss, and that ground buss is located next to the buss where all the AC neutrals terminate. I have a wire running from the AC neutral buss to the safety ground buss bonding them all together there, then wire (I have #6, but I'm going to increase the size to #4, or #2 if I can fit it in the conduit) running from the system ground buss to the ground rod.

If you find system (safety) grounds for AC and DC should be separate please let me know. I've got lots of re-wiring to do if so , but from what I've read, and questions I've asked, they should all be tied together in one place with only one connection to the ground rod.


--If you can, locate the ground rod in a garden area that gets watered regularly ( I don't, I plan to move it). Dry desert earth doesn't conduct very well or make a good ground.
A friend suggested placing it right by the outside faucet you use the most. Make a drain area filled with small pebbles/beach rock under the faucet to invite all the runoff to soak in, heading straight down. He also gave me a couple of tricks to help sink the ground rod further down.
Care to share those tricks?...I'm going to drive a new ground rod


--I'm not sure if lightning is an issue where you are, but if it is, (even occasionally) you should have lightning protection in:

1. Combiner box
2. Something in the wind generator, but I don't know what as I'm not familiar with those, and I would imagine in the wind turbine rectifier
3. Charge controller
4. Inverter
5. Input from generator
6. Main AC panel and any sub panels

Haven't seen any lightning here yet but I was thinking protection on the wind turbine at the very least. Refer to above mentioned thread on lightening and grounding. A lot of folks don't think it is a very good idea to protect your system by sending a lightning strike down your conduit into your system where it may very well fry everything. It appears that many have opted for a separate conduit away form the system wiring and keeping it outside the house.

There's so much about lightning and sooooo many theories. It's so confusing. I've opted to do what the mfgr for my solar (outback and midnight solar) recommend and used the lightning protectors below. They shunt all energy from a lightning strike to the system ground and out to the ground rod. These are what I'm using at each of the spots mentioned above: http://store.solar-electric.com/deliar.html I hope I don't ever find out if they're effective

I have noticed quite a variety of opinions about some grounding procedures and even more seem to differ about lightning protection. It really has made me stop for a minute to think about how I want to go about this.

If you read into the disagreement you find it comes down along two sides of a line defined mostly by building codes. Almost all of the solar installations north of the border are grid-tied and those who have sunk thousands into their systems are starting to second guess the inspectors grounding requirements that are geared solely to safety at the expense of their equipments' well being.

Lightning protection on my wind turbine is something that I am really thinking I will be sending outside, down to the ground and not through my system...

Originally Posted by BajaGringo

Sorry Larry - the brand is SineTech and the model is a PM-3000H-24. Attached is some info on the unit. I don't believe they are stackable...

I am not familiar with that inverter, but it appears to have most of the bells and whistles that you would want. Was it very expensive?

As far as lightening protection, the more grounds the better. We recently had a very close strike to our house. No damage except for 2 things. the next morning my wifes lap top computer was dead. The computer was just sitting on the desk, not plugged into anything, not charging. Now it is dead. My serius radio boom box uses a wall wort transformer to work on house power, and the transformer somehow got fried, found another one that put out the same voltage and now the radio works again. Lightening does strange stuff. If you get a direct all bets are off. No matter how well you are grounded it is probably going to burn out everything.
Larry

Good one... a real consideration... thanks

That inverter goes on eBay for something like 1200. So far it has worked flawlessly. How do you have your system set up for lightning protection Larry?

This is an awfully basic question, in light of such detailed, technical posts. But can anybody tell me approximately how much one spends per year on batteries for their solar power systems?

The batteries in our system have a ten year life, at least they are supposed too, we're on year three now only maintainance is some distilled water on occassion, well just once so far, our system plus the solar hot water system was under 10,000.... In this day and age the best way to go in my book.

Originally Posted by Msterieus

This is an awfully basic question, in light of such detailed, technical posts. But can anybody tell me approximately how much one spends per year on batteries for their solar power systems?

the better question is what is the cost per kilowatt ... that is the unit of measure we are charged for our power and what most use in planning their system .. I think.. at least that was what I had been using..

Or one just spends what ever it takes to get to the level of production which is needed, without concern for cost... of production...

I don't have a system.. only had planned to build one for the house.. sometime back..

Still is a good idea.. given the uncertain times we appear to be entering into.. (Stephen Hawkings statement about finite resources and population growth)

Something that has and apparently will never catch on.. "zero population growth", coupled with decreased "wants" and a shift towards what is "needed"..

But, then that just starts a whole lot of new arguments about all kinds of stuff... doesn't it...

Old age does have it's benefits.. I don't really have to worry about 20, 30 or 40 years from now... if I make it through this day.. I'm happy..

And today, is a nice day... will enjoy it and a watching the rerun of the Tour de France

On top of which, the infrastructure here in Baja cannot sustain the additional output required by many, power often does go out and sometimes for days, our system is set to maintain a full charge at all times with a back-up to the grid if needed which is very rare in itself.Next major issue facing us here is H2o now that one am at a loss for, anyone know if wells are permitted, have been thinking about it, but haven't researched it. Think the best one can do here is to learn to be as self-sufficient as you can be.

Originally Posted by Msterieus

This is an awfully basic question, in light of such detailed, technical posts. But can anybody tell me approximately how much one spends per year on batteries for their solar power systems?

You will get a different answer to that question from everyone you ask. Some advocate that you buy cheap batteries to start with so that when you ruin them you won't be out so much money. I disagree with that logic, I say start out with good sealed batteries and a good charge controller the first time. I got lucky and met a guy whos business is to replace battery banks for large industial companys and govrnment installations. The first set of batteries I got from him were 2 years old, I paid him $400, and used those batteries for 7 years at which time I sold them for what I paid for them originally and bought some more from him for $600. I have had these for about 4 years. So all in all I have $600 invested in the last 11 years, right around $50 per year.
Larry
PS The first set of batteries that I sold 4 years ago are still going strong, they are Absolyte llp and are now 13 years old.