Thickness and number of windings for 12 or 24 volt 17 foot wind turbines?

[joestue]

transmission line cost and efficiency obviously follow volts^2, so when i buy some land in the middle of nowhere and solar cells/wind.. they are going to be wired for at least 400 volts.

lets talk about inverters.

it doesn't really matter what voltage you get, efficiency is going to be about the same, favouring the higher voltage due because of higher manufacture costs for lower voltages.
name brand and cost is going to determine quality here more than anything.
why? because they all use mosfets to turn 12/24/48vdc into 200/400 to make AC
a fet's Rds(on) approximately follows the square of the voltage rating for the same silicon.
the market is pretty saturated for 12vdc inverters.. so although it seems like an expensive unit is better.. often its not, as in the case of that 48v $450, 4Kw inverter. i don't think you could get a 12vdc inverter for the same price and quality.


electrical machines don't care if they are wound for 12 volts or 48 volts, so comparing a geared up 12v to a 48 v direct drive is not a valid metric, i will get the same efficiency from a geared up 400 volt as i will a geared up 12volt, at the machine terminals.
but you're telling me to run 2/0 down the tower? i think not.
i'll put the rectifier on the tower and run two 12 awg lines down the tower 500 feet before you even buy the 100 amp rectifier block and heat-sink.

there's even been threads about synchronous rectification for 12v turbines.. is it worth it? depends how much that 10% loss means to you...

storage..

batteries are pretty reliable, the smaller the cell, generally the less reliable they are.
except for the mass produced cells, like 18650's, AA, 2/3rds C and D cells.
for 12v lead acid batteries, the last string on the positive side generally fails first.
but if you got 2 volt cells and are thinking that 2x 24 in parallel is going to be more reliable than 1x48?
-only if you don't record amp hours per cell, and define reliability as still putting out nominal volts.
in this case, 2x 24 volts will be twice as reliable, but each cell still has the same failure rate as 1x48.

with 48 v you can remove one and still use the battery at 95% capacity, try doing that with 24v or 12v.
so 48 wins there.
(hybrid car manufactures and submarines stopped at 200-300 volts because that's a sweet spot for reliability in that situation at the time.)


CFL lighting.

I find it hard to believe that 12 volt CFls are more efficient than 120vac fluorescents.
if that's the case then there's a market for more efficient ballasts, (like maybe get an electronic one?)
and did you get these numbers from a light meter or the manufacture???
if you really want to go there, you might as well light your house with low pressure sodium, or High pressure sodium, or HID

if the only reason you're going for 12 v is for the lights.. i don't know what to say here.

appliances...
even 120vac is too low for the current they draw!
buy a VFD off ebay to run the 120vac refrigerator, they don't care what the input voltage looks like, as long as your power source can take a capacitive input filter load. if it can't see if it will handle it with a choke installed.
you're SOL for heating with low voltage dc anyway.
you can even use the same VFD to run the furnace fan.

what even runs off 12/24 vdc these days?
most electronic loads no longer care if they get 85 vac or 264 vac, its boosted to ~380vdc anyway.

[fabricator]

Guys n Gals;

If I knew how to I would split this thread off to preserve the original question which seems to have gotten lost. Maybe its me that is lost?

I am in the middle @24 Volts but don't have any intention of joining in the voltage wars.

I will make a blanket statement, however:

Blanket Statements are a bad thing [TM]

 

Tom

O Thimk swaro got a lot of information, possibly a little too much

[rossw]

Ok, now I really believe an apology is in order from Ross for the village idiot post, that kind of conduct by a moderator is certainly uncalled for.

1. I never asked ot be made a Global Moderator.
2. I forgot how "thin skinned" some people were - the term "VI" wasn't meant
    to be offensive - and certainly in my circles it wouldn't have been.

3. Not withstanding that, I unreservedly apologise for the reference and will
    now go back and remove it from the original post.

[fabricator]

A classy act, thank you.

[Madscientist267]

Ok, so now that the fire is out, and since this thread is all jacked up anyway, will someone answer my question now about parallel vs serial?

Steve

[fabricator]

Ok, so now that the fire is out, and since this thread is all jacked up anyway, will someone answer my question now about parallel vs serial?

Steve

Well, as far as I know in higher voltage systems the most efficient way to do it is have however many paralell strings run into a buss box then just make one series jump in the box, always pull the pos and neg from opposite ends of the paralell strings to the buss bars, there is an example in a post i made a page or two back.

[rossw]

The bottom line is, don't try to tell me that a 48 volt system is "more efficient" as a generalization, just because it takes smaller copper, because I'll prove you wrong.

Now we're getting to the nitty-gritty of it. Generalizations in general, are bad. I believe your post was also in similarly "general" terms, so you're guilty as well

The bottom line, when everything is said and done, is the cost per kWh in equipment, maintenance and repairs on the system spread out over several years, and that includes eventual battery replacement and recycling of your old batteries.

Thats only part of the TCO. You need to factor in any oportunity losses (things you couldn't do because your system wasn't up to it), and unnecessary replacements of unrelated equipment (caused by a poor choice of equipment - SMPSs damaged by spikes, for example), losses of frozen foods because your freezer didn't stay cold, etc etc.

I've kept immaculate records on everything I've done and I estimate my cost at battery replacement time to be 14.7 cents per kWh spread out over 10 years on my 12 volt system, using today's prices and adjusting for 2% increase in the cost of batteries, per year, after 10 years.  The cost of grid power is around 10.5 cents, so I still can't compete with the cost of grid power today.  But in 10 years I'll bet I can.  What's your figures on your 48 volt system?

I *KNOW* mine is more expensive than it could have been - but thats my *choice*. That I *chose* a larger inverter than I could have squeeked by with, that I *chose* more solar panels than I oculd have managed with, that I *chose* to use heavier copper and better luggs and heavier copper bar, and nicer AGM cells etc.

All that said, and based on the energy I've *USED* my power based on your criteria above (total expenditure, total power used, 10 years) I have arrived at 28c/kWh. Thats already pretty close to the cost of "grid power" around here - people are paying around 22-25c/kWh, but thats going up every quarter and people have been warned it will be 30-50% more in 12 months (minimum, some are warning of 100% price increase in that time).

If I were to re-calculate based on my "potential to produce", my cost would be under 19c/kWh. (The reason is that once my batteries get to "Absorb" state, I'm only using about 75% of my panels output, and in "Float" I'm using less than 30%... I only have 72 kWh of batteries, but as I actually *produce* substantially more than I *use* there's little point in getting more battery capacity. I should probably be using it to (pre)heat the domestic hot water, that'd help "use" some of the extra "potential power" each day.

(the 28c is Australian - at the time I built all this, that would be about  USD 21c)

[Madscientist267]

So rather than several strings in series tied in parallel, there are groups that are in parallel which are tied in series...

ie:

Instead of:

(-)
|
 === - [   ] + === - [   ] + === - [   ] + ===
|                                                                    |
 === - [   ] + === - [   ] + === - [   ] + ===
|                                                                    |
 === - [   ] + === - [   ] + === - [   ] + ===
                                                                     | (+)

you have:

(-)
|
=== - [   ] + ===
|                          |
=== - [   ] + ===
|                          |
=== - [   ] + ===
|                          |
=== - [   ] + ===
                           |
 ==========
|                         
=== - [   ] + ===
|                          |
=== - [   ] + ===
|                          |
=== - [   ] + ===
|                          |
=== - [   ] + ===
                           |
 ==========
|                         
=== - [   ] + ===
|                          |
=== - [   ] + ===
|                          |
=== - [   ] + ===
|                          |
=== - [   ] + ===
                           | (+)

Right?

Personal Disclaimer: ASCII art sucks to begin with... and I'm not much of an artist... 

Steve

[rossw]

Well, as far as I know in higher voltage systems the most efficient way to do it is have however many paralell strings run into a buss box then just make one series jump in the box, always pull the pos and neg from opposite ends of the paralell strings to the buss bars, there is an example in a post i made a page or two back.

I think I've previously posted my battery arrangements here - but incase they're too hard to find I'll re-post here to.

Basically, I have 3 parallelled strings each of 24 series cells. Each series string has its own fuse and isolator before the "common bar".

This allows me to easily/trivially isolate one bank at a time, let it sit, measure individual cell voltages etc, and bring it back on-line.

200 amp, 600V DC rated HRC fuses and 500 amp isolators (keys removable when turned off)
[img width= height=]http://house.albury.net.au/13sep2010/thumb.100_4591.JPG[/img]

Primary and Secondary strings (on plinth) and tertiary (on floor), inverter, charge controller, PV metering, turbine control etc on wall
[img width= height=]http://house.albury.net.au/23may2010/thumb.100_4463.JPG[/img]

[fabricator]

This is what I have.
 24VDC Series Bus.pdf (146.86 kB - downloaded 213 times.)

[fabricator]

Well, as far as I know in higher voltage systems the most efficient way to do it is have however many paralell strings run into a buss box then just make one series jump in the box, always pull the pos and neg from opposite ends of the paralell strings to the buss bars, there is an example in a post i made a page or two back.

I think I've previously posted my battery arrangements here - but incase they're too hard to find I'll re-post here to.

Basically, I have 3 parallelled strings each of 24 series cells. Each series string has its own fuse and isolator before the "common bar".

This allows me to easily/trivially isolate one bank at a time, let it sit, measure individual cell voltages etc, and bring it back on-line.

200 amp, 600V DC rated HRC fuses and 500 amp isolators (keys removable when turned off)
<img src="ttp://house.albury.net.au/13sep2010/thumb.100_4591.JPG">

Primary and Secondary strings (on plinth) and tertiary (on floor), inverter, charge controller, PV metering, turbine control etc on wall
<img src="ttp://house.albury.net.au/23may2010/thumb.100_4463.JPG">

Taht is one impressive system, how many amp hours do you have there?

[rossw]

Taht is one impressive system, how many amp hours do you have there?

The cells are 2V, 500AH at C10,  484AH at C8. I draw them down at about C75 so place your guess at effective capacity

3 strings in parallel would see a "nominal" rating of 1500 AH - but we really should be talking in watt-hours - then you can directly compare battery banks of various constructions, voltages etc. This lot should be good for nominally 72 kWh.

[fabricator]

Very nice. mine should be around 48 kwh.

[ChrisOlson]

Now we're getting to the nitty-gritty of it. Generalizations in general, are bad. I believe your post was also in similarly "general" terms, so you're guilty as well

I'm guilty of a lot of things.  But I must say it irritates me a bit when people start claiming that in order to have a "real" system it has to be 48 volt.

The poor fellow that started this thread asked about options, not a big System Voltage War with some people getting all bent because somebody else runs an off-grid system on 12 volts, and they think 48 volt is the Gold Standard Of Off-Grid.

If swaro only has a good selection of 50 Hz 12 volt inverters in Sweden, then that's what you use and build.  It's a viable option, but will be a bit of a challenge with a 17 foot turbine.  Telling him that it's not viable, just because you think it's not the Gold Standard Of Off-Grid is bad information.  All the power in Sweden is 230 volt, 50 Hz, and that sort of equipment is just not common in 24 or 48 volt stuff where he lives.  My father and mother-in-law live in Lungvi and they got solar panels and an inverter - 12 volt - that's what's common and affordable over there.
--
Chris

[rossw]

I'm guilty of a lot of things.  But I must say it irritates me a bit when people start claiming that in order to have a "real" system it has to be 48 volt.

"it irritates me" when people also put out - without qualification or limitation - that modified sinewave, low-voltage systems will do everything anyone ever needs to live off-grid too.

The poor fellow that started this thread asked about options, not a big System Voltage War with some people getting all bent because somebody else runs an off-grid system on 12 volts, and they think 48 volt is the Gold Standard Of Off-Grid.

You missed the point. I shouldn't be surprised. I wasn't geting bent because you were using a 12V system. Hell, I couldn't care less if you used candles and lived in a cave. Really. But what DOES irk me is when someone suggests or recommends something that simply isn't up to the job it's claimed. If you'd put in the limitations and exceptions you've applied subsequently, I wouldn't have even commented in the first place.

If swaro only has a good selection of 50 Hz 12 volt inverters in Sweden, then that's what you use

Of course.  Oh, unless you insist on re-inventing and re-building everything from the ground up

It's a viable option, but will be a bit of a challenge with a 17 foot turbine  Telling him that it's not viable, just because you think it's not the Gold Standard Of Off-Grid is bad information.

Suggesting that anyone should just go with 12V/MSW without any indication or hint that there may be limitations is equally "bad information".

All the power in Sweden is 230 volt, 50 Hz, and that sort of equipment is just not common in 24 or 48 volt stuff where he lives.

If it was easy, anyone could do it.  It's *EXACTLY* the same here, mate.  230V, 50Hz, and I had to hunt far and wide to find ANYONE that would supply what *I WANTED*. I was all ready to import it because nobody had it. And hell, did I pay a premium for it! The inverter cost me $10,000 alone. Plus freight. And that was after I sweet-talked them down from the $13,800 it was supposed to be.

[windvision]

Hey Rossw...................give it up. Geez

[bob g]

wow, i missed a perfectly good argument ?

that isn't like me!

here is my take,

you learn to live with who you brought to the dance!

or in other words you work with what you have or can afford, that is just reality.

as for 12, 24, 48 or 63.4vdc systems (ok i threw in the last one)

there are so many factors involved in my opinion, and it all depends on what ones needs are, what you got to work with
and probably more important how you can work around limitations.

i see a lot of folks getting all knotted up over efficiency of a single component without regard to how it might work into the
overall efficiency of the total system.

its pretty easy to find a modified square wave inverter that it better than 90% efficient however how efficient is the system?

motors will run on modified square wave, but they run hotter, so the efficiency of the motor is lower, thankfully motor loads
are generally short duration comparatively speaking or more folks would understand this relationship much sooner.

i suppose it also depends on if your system is only windpower based, if you have a cogen or hydro or some other power source
that can be located very closely to the battery bank, perhaps a 12 and certainly a 24 volt system might compete well with a 48volt system,, line losses and cost of copper is a serious consideration these days with copper on the stock exchange trading at 4.25/lb

another thing i would like to point out, that is the existence of telecom inverter systems, such as the exetech mx serious
they are bloody expensive new, but if you watch they can be had surplus for a price that cannot be beat. generally they are always 48volt and generally they always arrive in working order.  exeltech will repair them for a very low cost, they are modular, fairly efficient,and about bullet proof.  i bought a 4kwatt pure sine wave rack mount for 500 bucks a couple years ago, and another 30kwatts worth last year for a similar cost per kwatt.  they can be setup as redundant n+1, split phase or three phase. and they are second to no one in having the lowest distortion in the industry, mtbf of over 20 years.

having said all that i wish they were 24volt versions, only because i have a serious investment in R&D invested in high efficiency charging capability at that voltage, something that i have not been able to match yet at 48volts.

if i were heavily reliant on wind power, my genny would be wound for as high a voltage as i could get away with, brought down the tower as wild ac and processed to fit my system down at the power room.

without concern for wind i think i could design a system at 12volts and certainly 24 that would compete with 48volt systems, up till i had to connect an inverter wherein is the problem, i can't see how to get around the efficiency hit one takes at the load feeding it with anything other than pure sine wave.  not many 12volt pure sine wave inverters made in larger sizes commonly available in the higher voltages.

just my opinion

not that anyone asked

bob g

[ChrisOlson]

The inverter cost me $10,000 alone. Plus freight. And that was after I sweet-talked them down from the $13,800 it was supposed to be.

LOL!  It's amazing how easy it is to not be able to see the forest for the trees.  You just illustrated my whole point in grand style.  I got $5,300 in my whole system - wind turbines, solar panels, towers, batteries, inverters, wiring, panels, generator - $5,300.

Now, I don't sit in front of a 1,000 watt big screen TV, drinking cold beer out of a 'fridge turned up to Max Cold, with a 1.5 kW air conditioner blowing on me to keep me nice and comfy when it's 95 degrees outside.  But if I wanted to spend another 5 Grand on my 12 volt system, to get up the cost level of the 48 volt Gold Standard Of Off-Grid, I probably could.

Limitations?  All it takes is money and there is no limitations.  Right?  I believe swaro said he just is not going spend no 10 Grand on an inverter.  So he's going to have to be Third World like the rest of us who don't have the 48 volt Gold Standard Of Off-Grid.
--
Chris

[ChrisOlson]

i can't see how to get around the efficiency hit one takes at the load feeding it with anything other than pure sine wave.

Just not the case anymore with some of the newer modified sine inverters, Bob.  Our 'fridge is the single biggest power user in our house.  I've amp checked it several times on both modified sine inverter power and "clean" generator power, and it draws the identical .90 amps on both @ 115 volts.  In some of these newer modified sine inverters they put more "steps" in the sine wave and the motor can't tell the difference.

Even our microwave oven transformer does not "buzz" on modified sine power.  The one and only thing I've found that doesn't work with it is digital clocks - they tend to "drift" and don't keep perfect time on modified sine wave.
--
Chris

[bob g]

Chris

thanks for the input on the newer msw inverters,

i do have a question though,

once you go to all the trouble to make several steps, you might as well go all the way to pure sine wave design?

unless the msw is more apt to handle brutal loads? or some other reason?

because my system is a dual voltage one, 24 and 48, reasons are two

1. i got a place to split up aging good batteries and get the last of their useful life out of them, and

2.  the 24 volt side is basically for such loads and i haven't found 48vdc equivalents for, such as certain specialized pumps
and control systems, relays etc.

the 24 volt side could live with msw and i would certainly take a look at such a unit in the 2-3kva class that could be used as
a back up for my 48volt system, covering critical loads such as the refrigeration  loads.

does aims make a good tough 24 volt 2-3kva unit that has proven reliable and priced in the 500 dollar range? or will it take more money?

bob g

[rossw]

LOL!  It's amazing how easy it is to not be able to see the forest for the trees.  You just illustrated my whole point in grand style.  I got $5,300 in my whole system - wind turbines, solar panels, towers, batteries, inverters, wiring, panels, generator - $5,300.

FFS, you're stomping on me for not taking into consideration other peoples local limitations, but you're happy as larry to crap on me without the same courtesy.

I don't suppose you ever considered local regulations, or some of the insanely expensive equipment I host for other people - for example, I host one of the six "atmospheric research systems" sensors in Australia. They're a mere $80,000 each. And they're hard to get, and I don't suppose the people who own it would be particularly happy if I plugged it into a squarewave inverter and blew the cr@p out of it.

Now, I don't sit in front of a 1,000 watt big screen TV, drinking cold beer out of a 'fridge turned up to Max Cold, with a 1.5 kW air conditioner blowing on me to keep me nice and comfy when it's 95 degrees outside.  But if I wanted to spend another 5 Grand on my 12 volt system, to get up the cost level of the 48 volt Gold Standard Of Off-Grid, I probably could.

Nor do I. And 95 degrees is nowhere near hot - we get over 115 - but I still don't have aircon.

Limitations?  All it takes is money and there is no limitations.  Right?  I believe swaro said he just is not going spend no 10 Grand on an inverter.  So he's going to have to be Third World like the rest of us who don't have the 48 volt Gold Standard Of Off-Grid.

I supplied "similar" 6KW 48V->240V inverter to someone else recently - even at our inflated Australian prices, it was only about 15% of the price of mine. That option simply wasn't available to me *AT THE TIME*.

To quote someone else: give it a fracking rest.

[ChrisOlson]

once you go to all the trouble to make several steps, you might as well go all the way to pure sine wave design?

I don't really know.  I've had some modified sine inverters that are just horrible.  They'll make the battery charger for your laptop hum and get very hot, make microwave ovens buzz really bad, ceiling fan motors will buzz loudly, etc..

I have a high speed bench grinder in my workshop that has a motor in it that those MSW inverters that make things buzz will not start.  If I turn on my drill press first, then turn on the bench grinder it will start and run.  These AIMS inverters I got now start that bench grinder just like it's on generator power and they don't have any of the problems with stuff buzzing or getting hot.  But they still won't run digital clocks and get them to keep time.

I got a Schumacher 2 kW modified sine inverter, too, that I run my well pump with and that's another one that will start that bench grinder motor with no problems.  The Schumacher does make a microwave oven buzz pretty good though, and my 'fridge draws .94 amps instead of .90 with it, so it's power isn't quite as "clean" as the AIMS units.

The other thing I've found with the AIMS inverter is that it drops its voltage down to about 97-98 under no load and you have to put about 5 watts load on it to get it to raise its voltage to 110.  As the load increases on it it continues to raise the voltage up to the full 120 at full rated output.  During heavy surge loads I've seen it at 125.  So if you have some device that absolutely requires at least 110 but the device draws less than 5 watts it might not work right.

does aims make a good tough 24 volt 2-3kva unit that has proven reliable and priced in the 500 dollar range? or will it take more money?

I think fabricator has a 5 kw 24 volt and he also has a smaller 2.5 kW 24 volt, both under $500.  They also have a 3 kW 24 volt pure sine unit that's more money (around $800), and they have their industrial line of 7 kW 24 volt inverters that have bigger heat sinks, deliver double their rated power for 9 seconds, and are available in 120 or 240 volt.  But those are over $1,500.  I think freejuice has one of those industrial ones, but his is 48 volt.
--
Chris

[smidy]

here is a link to a lokal suplier in sweden that sells inverters http://24volt.eu/osc2/catalog/index.php?currency=EUR&cPath=25 , there you got prices for inverters in the range from 12 volts to 48 volts in € there are both msv and sinevave and of course it is in swedish so i translate msw=modifierad sinus and pure sinevave=ren sinus that is about wath he got lokal, but there are probably other supliers in sweden to but i think the prices are simular. for example 400w pure sinvave in 12 volt is 613.07€ and 400w pure sinevave in 48 volt is 681.19€, expensive YES but the differance betwen 12 and 48volts is so smal that the inverterprice that it dosent mather for wich systemvoltage he will shoot for. i hope this will calm the war betwen chris and ross 

[DanB]

We all get a bit too snitty here at time, I apologize as well.

The voltage issue has been beaten into the ground anyhow.

regarding modified vs sine wave inverters - my experience has been that almost always modified sine wave units work fine, and the inverters themselves are generally more efficient.  However some stuff that you plug into them is less efficient on the modified sine wave.

Some stuff will not work off them - I've seen certain satellite internet modems that refuse to work with them.  I've seen some cordless drill charges melt when plugged into them (in my case, it was almost a fire on my workbench while I was sleeping!) - and I've seen some cordless drill chargers simply not work at all.  I've seen some laser printers that refuse to work with them.

But most of the time they work fine and most of the folks in my community here, still use them (most folks here are still on 12 Volts)

Some of the less expensive inverters are not grounded properly - if you attempt to ground them to a breaker box in a 'normal' house that's wired and grounded to code - you'll cook the inverter immediately.

So I expect, no matter what you buy - if it is a quality unit that your electrical inspector will 'sign off' ~ it's likely going to be fairly expensive no matter what voltage you shoot for.  That said - some are less than others...  it depends on what features you require.

[ChrisOlson]

Some stuff will not work off them - I've seen certain satellite internet modems that refuse to work with them

Oh yeah, that's one thing I should mention for Bob because he asked about the AIMS units I got.  I got a little battery charger thing that charges AA and AAA batteries and I keep batteries charged all the time for my wireless anemometer and outdoor temp sensor because I have to change batteries in those things every two weeks in cold weather.  That charger does not work with my inverters if it's the only thing plugged in.  If the 'fridge or something comes on the house so the inverter raises the line voltage to at least 110, then the red charge light comes on on it.

I attribute to the fact that the little thing must draw less than 5 watts and it doesn't have enough load to bring the inverter out of idle mode.

But I should also mention that I had that problem, only worse, with the Xantrex inverter I used to have.  That Xantrex would go into idle mode and it pulsed the current in the line searching for a load.  I had some LED night lights that wouldn't come on with that inverter unless I turned something else on to increase the load on it and bring it out of idle mode.  That was a pure sine inverter.

I've never used an inverter yet that didn't have some sort of glitch someplace.  But I've had ones that were a lot worse than what I got now.  And I've found the modified sine inverters are definitely slightly more efficient in the DC->AC conversion than pure sine.  Most times it's a trade-off because some of your AC stuff might not be as efficient on modified sine.  My Gibson 'fridge is the "benchmark" I use to test a MSW inverter - if it draws .90 amps with the compressor going and 3.46 amps with the defrost heater going in it, then I consider it a "good" inverter.  If it draws more than that I consider it a "poor" inverter with "dirty" power output, and I sell the thing on eBay and get rid of it.  I've probably bought, tried and sold a dozen different inverters over the past 3-4 years because they didn't perform as advertised.
--
Chris

[DanB]

yes, I've seen lots of inverters with search mode that wont power up very small loads even w/search turned all the way down.  That's not what I meant though by certain chargers just refusing to work...  I never use search mode anyhow because my satellite modem, and my fridge  - are always on.

Pros and cons with all this stuff.  I've been running SW series trace inverters for a while now.  My last one was an SW 2512 (2500 Watt, 12 Volts) - it worked fine and pulled loads that my 6000 Watt honda generator (which is only 3000 Watts on a single side of 120VAC) wouldn't.  the 4000 watt 48V unit I have now has been flawless and seemingly bomb proof - I really push it sometimes.  I really like the outback inverters, however I've been using the older trace SW ones here, because I got them used for a 'bargain'.

[ghurd]

I was at 12 Volts here until I built my first 17' machine - and decided to change everything (which involved removing all the 12 volt lights/pumps/etc ~ new inverter, charge controllers, re-wiring solar panels and giving away a few solar panels) at that time. 

Dan,
I often wondered why people in a situation such as yourself would not leave a small 12V system in place.
The wire is still burried, the 12V items are still there, you must have a small tower and enough stray parts to throw up a small 12V turbine in 10 minutes, and probably have a few functional batteries for it?  Why not use the stuff?
G-
 

[DanB]

Hi Ghurd -
I really don't have much spare stuff around here to do a decent 12V system - I could do it, in sort of a sloppy way, but I wouldn't really have use for it.  Usually if I have spare stuff around I find a better home for it.

[swaro]

Hi Smidy
I have seen the home page you recommend. But I have also seen a web site from Scotland that sells 48 volt converter pure wave to about 1300 euros.
http://www.cclcomponents.com/product.asp?ID=1460

I myself am not quite sure if I should order from scotland, if I order from Sweden you can get some assurance that you may almost forget when ordering abroad.
You may be able to see the differences or advantages and disadvantages of it from Sweden who 24volt sell and the sold from Scotland. I myself am not too familiar with the converter.

Hi fabricator,
It was very good conversation topic, I learned a lot, I hope everyone got something good from the heated debate.

[cdog]

Anyone have any opinions on exeltech?
Stand alone, or even one of their industrial ''rack'' units?

[fabricator]

Hi Smidy
I have seen the home page you recommend. But I have also seen a web site from Scotland that sells 48 volt converter pure wave to about 1300 euros.
http://www.cclcomponents.com/product.asp?ID=1460

I myself am not quite sure if I should order from scotland, if I order from Sweden you can get some assurance that you may almost forget when ordering abroad.
You may be able to see the differences or advantages and disadvantages of it from Sweden who 24volt sell and the sold from Scotland. I myself am not too familiar with the converter.

Hi fabricator,
It was very good conversation topic, I learned a lot, I hope everyone got something good from the heated debate.

Every once in a while you gotta add a little ozone to the air to give it that fresh smell, like a big lightning storm just rolled through   And BTW, YOU started this crap storm!

[Madscientist267]

Naa... there's no testosterone in here... really... 

The silver lining would be the nitty gritty details of two (or more) very strongly opinionated people who both know their $#!+... I'll give it that...

Good reference material when coming back to look for that 'tie breaker'.

But sometimes... Jeesh! 

Steve

[bob g]

cdog:

i am not familiar with exeltech's stand alone inverters, but i am with their industrial rack mounted stuff
it is all first rate, rock solid and tough as nails

the rack mounted systems (mx series) have individual 1kwatt inverters inserted into the rack and the racks come in
3 or 4 sizes holding up to 6 inverters, and the control module, along with some optional cards that do other stuff.

the module inverters are hot swappable, and they rely on the control module to generate the sine wave signals that they
all sync to, unless one of the inverters ia a master in which case it controls all the other inverters.

exeltech advertises that they will repair any repairable failure for a flat fee, 150 bucks which isn't bad in my opinion
if you have a bad inverter, you simply pull it from the rack and continue to use the rest at a capacity of what they are capable of
and then send in the failed unit for repairs.

the racks are also stackable and one control card can control i think up to 15 inverter modules iirc for a total of 15kwatts

new the systems are very expensive, but they make the very cleanest sine wave on the market today advertised as under 2% thd
and usually measured at under 1% thd,   the older units were stated to have a 21 year mtbf, the system has worked out so well
that the have extended that to 40 years i have heard,, that is incredible.

these systems do come up as surplus from time to time, and are generally always 48volt front end units.
although exeltech will build them from 12, 24, 36, 48, 60, 72 and 108dc and they also state they will build to custom voltages as well.

my bet all the exeltech inverters are built to the same high standards

last i checked they are 100% built in the good old USA too

bob g