looking for big inverter

[[email protected]]

Does anyone make a large inverter? I'm exploring the idea of running
things entirely off-grid. So I'm exploring what all could be done with
various elements of solar, natural, and renewable power sources to see
if this might be practical and what constraints it may have when it
comes time to do this.

But one limitation I have found is that inverters seem to all be on the
small side and with only limited ability to "stack" them. The largest
I have seen is 6000 watts. The largest Xantrex model (besides their
three phase grid tie units) is just 5500 watts. It can be "stacked"
up to 2 units either parallel (120 volts only) or series (120/240 volts).
But 11000 watts is a little on the wimpy side and you can't parallel a
stacked pair.

I could just have multiple systems (probably 2 to 4). But that makes
more of a wiring nightmare. It would be easier to have a larger inverter.
And I would be more comfortable with having a single unit that does the
3-wire system for 120/240 volts integrated. I have no committment on the
DC side voltage, but I'd like to be sure it is within the range that can
be handled by common circuit breakers from Square-D and Cutler-Hammer.

The built-in charger in the Xantrex (and many other) units is also not
useful. For example, AC power sources might not be able to support the
peak demand, but I would certainly want to have them supplement batteries
in those cases. The goal of this is to be off-grid, not as a backup for
utility outage.

Anyone know of larger single-phase inverters that are in, or can be stacked
to be in, the 15 to 50 kW range at 120/240 volts?

Separate chargers (AC to DC converters) would also be nice, especially if
they can handle really weird power (wide voltage and frequency variation).

 

[TimPerry]

Does anyone make a large inverter? I'm exploring the idea of running
things entirely off-grid. So I'm exploring what all could be done with
various elements of solar, natural, and renewable power sources to see
if this might be practical and what constraints it may have when it
comes time to do this.

yes indeed.

the "Cadillac" is considered by some to be made by Liebert
http://www.liebert.com/dynamic/catprodlist.asp?pid=6&cycles=60HZ

at present one of my locations uses a 15 kW Powerware unit, upgradeable to
20K with more modules http://www.powerware.com/USA/default.asp?CC=1

other makers are GE and APC and MGC


mine uses a series bank of gel cells to produce 208V 3 phase. the conversion
process is continuous. in other words all the mains power is rectified to DC
then regenerated to AC. this gives you a warm fuzzy feeling when lightning
storms pass by and a couple dozen 'mission critical' computers and servers
are running.

 

[Bill Kaszeta / Photovoltaic Resources]

Does anyone make a large inverter? I'm exploring the idea of running
things entirely off-grid. So I'm exploring what all could be done with
various elements of solar, natural, and renewable power sources to see
if this might be practical and what constraints it may have when it
comes time to do this.

But one limitation I have found is that inverters seem to all be on the
small side and with only limited ability to "stack" them. The largest
I have seen is 6000 watts. The largest Xantrex model (besides their
three phase grid tie units) is just 5500 watts. It can be "stacked"
up to 2 units either parallel (120 volts only) or series (120/240 volts).
But 11000 watts is a little on the wimpy side and you can't parallel a
stacked pair.

I could just have multiple systems (probably 2 to 4). But that makes
more of a wiring nightmare. It would be easier to have a larger inverter.
And I would be more comfortable with having a single unit that does the
3-wire system for 120/240 volts integrated. I have no committment on the
DC side voltage, but I'd like to be sure it is within the range that can
be handled by common circuit breakers from Square-D and Cutler-Hammer.

The built-in charger in the Xantrex (and many other) units is also not
useful. For example, AC power sources might not be able to support the
peak demand, but I would certainly want to have them supplement batteries
in those cases. The goal of this is to be off-grid, not as a backup for
utility outage.

Anyone know of larger single-phase inverters that are in, or can be stacked
to be in, the 15 to 50 kW range at 120/240 volts?

Separate chargers (AC to DC converters) would also be nice, especially if
they can handle really weird power (wide voltage and frequency variation).

--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / [email protected] |
|------------------------------------/-------------------------------------|

Some examples (not an offer or advertisement, posted only for information):
(basically list prices)

XANTREX PV-SERIES LARGE INVERTERS & ACCESSORIES
PV "S" Series Inverters (2nd generation PV-series complete w/ DC & AC discos, nite disco, & isolation transformer)
Xantrex 100kW, HE, 3-ph 208Vac, LCD display, w/ 208/120vac iso transformer $81,100
Xantrex 100kW, HE 3-ph 208Vac, LCD display, w/ 480/277vac iso transformer $81,100
Xantrex 225kW, 3-ph 208Vac, LCD display, w/ 480/277vac iso transformer $128,846
PV Series Inverters
Xantrex 10kW Intertie Inverter, 3-phase 208Vac, LCD display $8,473
Xantrex 15kW Intertie Inverter, 3-phase 208Vac, LCD display $12,220
Xantrex 20kW Intertie Inverter, 3-phase 208Vac, LCD display $15,452
Xantrex 30kW Intertie Inverter, 3-phase 208Vac, LCD display $20,989
Xantrex 45kW Intertie Inverter, 3-phase 208Vac, LCD display $26,647

(Most Grid-Tie Models can not operate without a grid)

BALLARD INTERTIE INVERTERS
Grid-Tie Models (MSRP)
Ballard Ecostar 480V 75 kW inverter/transformer $61,500
Ballard Ecostar 480V 30 kW inverter/transformer $27,500
Ballard Ecostar 208V 30 kW inverter/transformer $27,500

SATCON LARGE INVERTERS & ACCESSORIES (MSRP)
AE-30kW PV Series Inverters
SatCon 30kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $30,555
SatCon 30kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $31,275
SatCon 30kW 1-ph 240Vac w/AC & DC discos, iso trans, display & comm port $36,110
Sub-Combiner w/ 3 100A circuits. For 30 or 50 kW SatCon inverters. $509
SatCon 6 to 10 Year Optional Warranty Extension for 30kW 3-ph. $2475
SatCon 11 to 15 Year Optional Warranty Extension for 30kW 3-ph. $4950
SatCon 6 to 10 Year Optional Warranty Extension for 30kW 1-ph. $2925
SatCon 11 to 15 Year Optional Warranty Extension for 30kW 1-ph. $5850

AE-50kW PV Series Inverters
SatCon 50kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $35,000
SatCon 50kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $35,910
Internal Sub-Combiner w/ 3 100A circuits. For 30 or 50 kW SatCon inverters. $509

SMA INVERTERS
Commercial/Industrial Inverter
Sunny Central 125kW Grid-Tie Inverter w/ transformer & discos $63,000

SatCon 6 to 10 Year Optional Warranty Extension for 50kW 3-ph. $2835
SatCon 11 to 15 Year Optional Warranty Extension for 50kW 3-ph. $5670

AE-75kW PV Series Inverters
SatCon 75kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $53,000
SatCon 75kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $54,095
Internal Sub-Combiner w/ 6 100A circuits. For 75 or 100 kW SatCon inverters. $955
SatCon 6 to 10 Year Optional Warranty Extension for 75kW 3-ph. $4293
3SC-75A-15YR SatCon 11 to 15 Year Optional Warranty Extension for 75kW 3-ph. $8586

AE-100kW PV Series Inverters
3SC-AE-100-60-A SatCon 100kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $66,000
3SC-AE-100-60-D SatCon 100kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $67,275
3SC-SC6 Internal Sub-Combiner w/ 6 100A circuits. For 75 or 100 kW SatCon inverters. $955
3SC-100A-10YR SatCon 6 to 10 Year Optional Warranty Extension for 100kW 3-ph. $5346
3SC-100A-15YR SatCon 11 to 15 Year Optional Warranty Extension for 100kW 3-ph. $10692

AE-135kW PV Series Inverters
3SC-AE-135-60-A SatCon 135kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $80,000
3SC-AE-135-60-D SatCon 135kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $81,460
3SC-SC9 Internal Sub-Combiner w/ 9 100A circuits. For 135 kW SatCon inverter. $1,435
3SC-135A-10YR SatCon 6 to 10 Year Optional Warranty Extension for 135kW 3-ph. $6480
3SC-135A-15YR SatCon 11 to 15 Year Optional Warranty Extension for 135kW 3-ph. $12960


Bill Kaszeta
Photovoltaic Resources Int'l
Tempe Arizona USA
[email protected]

 

[[email protected]]

| Probably much more capacity than you will ever want is the inverter at the
| Sylmar Intertie Station in California. It is used to send and receive power
| at -0.5-0-+0.5MV dc to ac at something like 1200A. It was manufactured by a
| Swedish company. You can find out its name by Googling. Will that be large
| enough?

I've seen pictures of that and some others like it. The shipping and
installation costs are gonna be a killer

 

[[email protected]]

| |> Does anyone make a large inverter? I'm exploring the idea of running
|> things entirely off-grid. So I'm exploring what all could be done with
|> various elements of solar, natural, and renewable power sources to see
|> if this might be practical and what constraints it may have when it
|> comes time to do this.
|
| yes indeed.
|
| the "Cadillac" is considered by some to be made by Liebert
| http://www.liebert.com/dynamic/catprodlist.asp?pid=6&cycles=60HZ
|
| at present one of my locations uses a 15 kW Powerware unit, upgradeable to
| 20K with more modules http://www.powerware.com/USA/default.asp?CC=1
|
| other makers are GE and APC and MGC
|
|
| mine uses a series bank of gel cells to produce 208V 3 phase. the conversion
| process is continuous. in other words all the mains power is rectified to DC
| then regenerated to AC. this gives you a warm fuzzy feeling when lightning
| storms pass by and a couple dozen 'mission critical' computers and servers
| are running.

You missed an aspect of my original quest. The power source is not AC.
The above mentioned units are UPSes that take AC in (DC is an intermediate
step). I'm looking for true inverters that take DC in, not AC. So a UPS
does not qualify.

 

[[email protected]]

| XANTREX PV-SERIES LARGE INVERTERS & ACCESSORIES
| PV "S" Series Inverters (2nd generation PV-series complete w/ DC & AC discos, nite disco, & isolation transformer)
| Xantrex 100kW, HE, 3-ph 208Vac, LCD display, w/ 208/120vac iso transformer $81,100
| Xantrex 100kW, HE 3-ph 208Vac, LCD display, w/ 480/277vac iso transformer $81,100
| Xantrex 225kW, 3-ph 208Vac, LCD display, w/ 480/277vac iso transformer $128,846
| PV Series Inverters
| Xantrex 10kW Intertie Inverter, 3-phase 208Vac, LCD display $8,473
| Xantrex 15kW Intertie Inverter, 3-phase 208Vac, LCD display $12,220
| Xantrex 20kW Intertie Inverter, 3-phase 208Vac, LCD display $15,452
| Xantrex 30kW Intertie Inverter, 3-phase 208Vac, LCD display $20,989
| Xantrex 45kW Intertie Inverter, 3-phase 208Vac, LCD display $26,647

These are 3 phase. I need single phase only.


| (Most Grid-Tie Models can not operate without a grid)

If that were th only issue, I'm sure I could find a way around it,
such as supplying some fake grid like power from a smaller inverter.


| BALLARD INTERTIE INVERTERS
| Grid-Tie Models (MSRP)
| Ballard Ecostar 480V 75 kW inverter/transformer $61,500
| Ballard Ecostar 480V 30 kW inverter/transformer $27,500
| Ballard Ecostar 208V 30 kW inverter/transformer $27,500

Smell like 3 phase to me.


| SATCON LARGE INVERTERS & ACCESSORIES (MSRP)
| AE-30kW PV Series Inverters
| SatCon 30kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $30,555
| SatCon 30kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $31,275
| SatCon 30kW 1-ph 240Vac w/AC & DC discos, iso trans, display & comm port $36,110
| Sub-Combiner w/ 3 100A circuits. For 30 or 50 kW SatCon inverters. $509
| SatCon 6 to 10 Year Optional Warranty Extension for 30kW 3-ph. $2475
| SatCon 11 to 15 Year Optional Warranty Extension for 30kW 3-ph. $4950
| SatCon 6 to 10 Year Optional Warranty Extension for 30kW 1-ph. $2925
| SatCon 11 to 15 Year Optional Warranty Extension for 30kW 1-ph. $5850

Well, at least there is a single phase one in there. Rather pricy. Maybe
it's all the grid-tie certification that adds to that ... plus the tranny.


| AE-50kW PV Series Inverters
| SatCon 50kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $35,000
| SatCon 50kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $35,910
| Internal Sub-Combiner w/ 3 100A circuits. For 30 or 50 kW SatCon inverters. $509

More 3 phase.


| SMA INVERTERS
| Commercial/Industrial Inverter
| Sunny Central 125kW Grid-Tie Inverter w/ transformer & discos $63,000

Scoured their web site last night. Anything over about 3600 watts is
grid-intertie at 3 phase.


| SatCon 6 to 10 Year Optional Warranty Extension for 50kW 3-ph. $2835
| SatCon 11 to 15 Year Optional Warranty Extension for 50kW 3-ph. $5670
|
| AE-75kW PV Series Inverters
| SatCon 75kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $53,000
| SatCon 75kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $54,095
| Internal Sub-Combiner w/ 6 100A circuits. For 75 or 100 kW SatCon inverters. $955
| SatCon 6 to 10 Year Optional Warranty Extension for 75kW 3-ph. $4293
| 3SC-75A-15YR SatCon 11 to 15 Year Optional Warranty Extension for 75kW 3-ph. $8586
|
| AE-100kW PV Series Inverters
| 3SC-AE-100-60-A SatCon 100kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $66,000
| 3SC-AE-100-60-D SatCon 100kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $67,275
| 3SC-SC6 Internal Sub-Combiner w/ 6 100A circuits. For 75 or 100 kW SatCon inverters. $955
| 3SC-100A-10YR SatCon 6 to 10 Year Optional Warranty Extension for 100kW 3-ph. $5346
| 3SC-100A-15YR SatCon 11 to 15 Year Optional Warranty Extension for 100kW 3-ph. $10692
|
| AE-135kW PV Series Inverters
| 3SC-AE-135-60-A SatCon 135kW 3-ph 480Vac w/AC & DC discos, iso trans, display & comm port $80,000
| 3SC-AE-135-60-D SatCon 135kW 3-ph 208Vac w/AC & DC discos, iso trans, display & comm port $81,460
| 3SC-SC9 Internal Sub-Combiner w/ 9 100A circuits. For 135 kW SatCon inverter. $1,435
| 3SC-135A-10YR SatCon 6 to 10 Year Optional Warranty Extension for 135kW 3-ph. $6480
| 3SC-135A-15YR SatCon 11 to 15 Year Optional Warranty Extension for 135kW 3-ph. $12960

Tons of 3 phase.


| Bill Kaszeta
| Photovoltaic Resources Int'l
| Tempe Arizona USA
| [email protected]

Much of this endeavor is aimed at being disconnected from the grid/utility.
I'm sure solar will be a big part of the system. Wind might be, too. And
I'll look for other possibilities such as waterfalls, wood burners, etc.
But feeding power back to the utility is just not where I'm going with this
at all.

 

[[email protected]]

| |> Does anyone make a large inverter? I'm exploring the idea of running
|> things entirely off-grid. So I'm exploring what all could be done with
|> various elements of solar, natural, and renewable power sources to see
|> if this might be practical and what constraints it may have when it
|> comes time to do this.
|>
|> But one limitation I have found is that inverters seem to all be on the
|> small side and with only limited ability to "stack" them. The largest
|> I have seen is 6000 watts. The largest Xantrex model (besides their
|> three phase grid tie units) is just 5500 watts. It can be "stacked"
|> up to 2 units either parallel (120 volts only) or series (120/240 volts).
|> But 11000 watts is a little on the wimpy side and you can't parallel a
|> stacked pair.
|>
|> I could just have multiple systems (probably 2 to 4). But that makes
|> more of a wiring nightmare. It would be easier to have a larger inverter.
|> And I would be more comfortable with having a single unit that does the
|> 3-wire system for 120/240 volts integrated.
|
| Using a single system gives a single point of failure.

True. So I might also consider redundancy and transfer switching. But
the Xantrex 2x5500 was just a bit on the wimpy side. If they offered a
7500 watt model that could be series stacked, that might be good enough.
Or if the 5500's could be connected with 4 units in a series + parallel
scheme to get 120/240 at 11000 watts, and double that to 22000, that
would do, as well. But I've looked at details and it's stacking is very
much limited. It has only one stacking cable (I assume is a phase lock
control, among other things).

 

[TimPerry]

You missed an aspect of my original quest. The power source is not
AC.
The above mentioned units are UPSes that take AC in (DC is an
intermediate step). I'm looking for true inverters that take DC in,
not AC. So a UPS
does not qualify.

they run on batterys... you just dont use the AC inputs for your application

 

[[email protected]]

| With used UPS's so plentiful, I would suggest an industrial one. Make
| sure it can be started from battery while off line.

That might be an option. But remember, this means tearing the thing apart
and connecting the DC to my external battery array. It also means being
able to handle a fairly wide DC voltage swing. I'm guessing many of the
industrial UPS controllers are going to see a lot of this as a "system
problem" and go into shutdown.

I'm not ruling out building my own. And industrial UPSes that get tossed
because of dead batteries no one realized could be replaced (I've seen it
happen) might be a nice source of parts, at least.

 

[[email protected]]

| [email protected] wrote:
|> On Thu, 2 Nov 2006 19:55:04 -0500 TimPerry
|>
|>> |>>> Does anyone make a large inverter? I'm exploring the idea of
|>>> running things entirely off-grid. So I'm exploring what all could
|>>> be done with various elements of solar, natural, and renewable
|>>> power sources to see if this might be practical and what
|>>> constraints it may have when it comes time to do this.
|>>
|>> yes indeed.
|>>
|>> the "Cadillac" is considered by some to be made by Liebert
|>> http://www.liebert.com/dynamic/catprodlist.asp?pid=6&cycles=60HZ
|>>
|>> at present one of my locations uses a 15 kW Powerware unit,
|>> upgradeable to 20K with more modules
|>> http://www.powerware.com/USA/default.asp?CC=1
|>>
|>> other makers are GE and APC and MGC
|>>
|>>
|>> mine uses a series bank of gel cells to produce 208V 3 phase. the
|>> conversion process is continuous. in other words all the mains power
|>> is rectified to DC then regenerated to AC. this gives you a warm
|>> fuzzy feeling when lightning storms pass by and a couple dozen
|>> 'mission critical' computers and servers are running.
|>
|> You missed an aspect of my original quest. The power source is not
|> AC.
|> The above mentioned units are UPSes that take AC in (DC is an
|> intermediate step). I'm looking for true inverters that take DC in,
|> not AC. So a UPS
|> does not qualify.
|>
|
| they run on batterys... you just dont use the AC inputs for your application

There are two issues with this:

1. Waste of money buying the AC->DC part I don't need
2. Connecting the DC circuitry to my external DC power source

 

[[email protected]]

| On 11/2/06 10:12 PM, in article [email protected],
|
|> You missed an aspect of my original quest. The power source is not AC.
|> The above mentioned units are UPSes that take AC in (DC is an intermediate
|> step). I'm looking for true inverters that take DC in, not AC. So a UPS
|> does not qualify.
|
| You should stop looking. You are in over your head. The typical UPS will do
| what you want if its rated is adequate. Just take out the battery and wire
| you dc to where the battery is connected. Then just do not use the rest of
| it.

I think not. Many UPSes do run tests and exercises on the battery inside
to check its charge level and charge acceptance quality. External batteries
could easily confuse them unless there is attached circuitry. It is NOT a
trivial, or even safe, procedure to connect a UPS to external batteries it
was not designed for.

A plain inverter works different than a UPS, too. A UPS expects a narrow
battery voltage range whereas many inverters operate on a wider range of
voltages.

Why is it that when I and many other people ask straightforward questions,
a lot of people seem to go out of their way to answer something else?
I know the difference between an inverter and a UPS and I am looking for
an inverter.

 

[Paul Hovnanian P.E.]

Does anyone make a large inverter? I'm exploring the idea of running
things entirely off-grid. So I'm exploring what all could be done with
various elements of solar, natural, and renewable power sources to see
if this might be practical and what constraints it may have when it
comes time to do this.

But one limitation I have found is that inverters seem to all be on the
small side and with only limited ability to "stack" them. The largest
I have seen is 6000 watts. The largest Xantrex model (besides their
three phase grid tie units) is just 5500 watts. It can be "stacked"
up to 2 units either parallel (120 volts only) or series (120/240 volts).
But 11000 watts is a little on the wimpy side and you can't parallel a
stacked pair.

I could just have multiple systems (probably 2 to 4). But that makes
more of a wiring nightmare. It would be easier to have a larger inverter.
And I would be more comfortable with having a single unit that does the
3-wire system for 120/240 volts integrated. I have no committment on the
DC side voltage, but I'd like to be sure it is within the range that can
be handled by common circuit breakers from Square-D and Cutler-Hammer.

The built-in charger in the Xantrex (and many other) units is also not
useful. For example, AC power sources might not be able to support the
peak demand, but I would certainly want to have them supplement batteries
in those cases. The goal of this is to be off-grid, not as a backup for
utility outage.

Anyone know of larger single-phase inverters that are in, or can be stacked
to be in, the 15 to 50 kW range at 120/240 volts?

At these power levels, you really might want to consider a 3-phase
distribution system.

The economics of 3 vs single phase is probably what dictates the 5 kW
upper end on the latter.

 

[[email protected]]

| [email protected] wrote:
|>
|> | With used UPS's so plentiful, I would suggest an industrial one. Make
|> | sure it can be started from battery while off line.
|>
|> That might be an option. But remember, this means tearing the thing apart
|> and connecting the DC to my external battery array. It also means being
|> able to handle a fairly wide DC voltage swing. I'm guessing many of the
|> industrial UPS controllers are going to see a lot of this as a "system
|> problem" and go into shutdown.
|>
|> I'm not ruling out building my own. And industrial UPSes that get tossed
|> because of dead batteries no one realized could be replaced (I've seen it
|> happen) might be a nice source of parts, at least.
|>
| All of the larger UPS that I have seen have had terminals for external
| batteries. Even ones as small as 1KVA often have them.

Generally these are for the battery systems they manufacture and have
specified. It's probably not a generic DC input.


| However, they aren't designed to take that large a dc voltage swing
| (other than the usual voltages present on a charging/discharging set of
| batteries). If the voltage swing takes the level down to the alarm and
| trip points then, yes, the UPS will act on it.
|
| Another point to watch out for is that inverters, particularly big
| inverters, normally have chargers that work off the crests of the input
| supply. They typically need a supply which isn't "squashed", e.g isn't
| like that produced by many small generators. A 1.5KVA inverter may
| easily need a 5kVA generator to run the charger at full capacity.

I'd rather have the chargers for any AC sources completely separate.

 

[[email protected]]

| [email protected] wrote:
|>
|> Does anyone make a large inverter? I'm exploring the idea of running
|> things entirely off-grid. So I'm exploring what all could be done with
|> various elements of solar, natural, and renewable power sources to see
|> if this might be practical and what constraints it may have when it
|> comes time to do this.
|>
|> But one limitation I have found is that inverters seem to all be on the
|> small side and with only limited ability to "stack" them. The largest
|> I have seen is 6000 watts. The largest Xantrex model (besides their
|> three phase grid tie units) is just 5500 watts. It can be "stacked"
|> up to 2 units either parallel (120 volts only) or series (120/240 volts).
|> But 11000 watts is a little on the wimpy side and you can't parallel a
|> stacked pair.
|>
|> I could just have multiple systems (probably 2 to 4). But that makes
|> more of a wiring nightmare. It would be easier to have a larger inverter.
|> And I would be more comfortable with having a single unit that does the
|> 3-wire system for 120/240 volts integrated. I have no committment on the
|> DC side voltage, but I'd like to be sure it is within the range that can
|> be handled by common circuit breakers from Square-D and Cutler-Hammer.
|>
|> The built-in charger in the Xantrex (and many other) units is also not
|> useful. For example, AC power sources might not be able to support the
|> peak demand, but I would certainly want to have them supplement batteries
|> in those cases. The goal of this is to be off-grid, not as a backup for
|> utility outage.
|>
|> Anyone know of larger single-phase inverters that are in, or can be stacked
|> to be in, the 15 to 50 kW range at 120/240 volts?
|
| At these power levels, you really might want to consider a 3-phase
| distribution system.
|
| The economics of 3 vs single phase is probably what dictates the 5 kW
| upper end on the latter.

Which 3 phase configuration would you suggest? Will it give me both 120
volts and 240 volts? (208 volts is not good enough because most things
for homes that need more than 120 volts need 240, not 208).

Know of any that are not "grid tie" types?

 

[TimPerry]

There are two issues with this:

1. Waste of money buying the AC->DC part I don't need
2. Connecting the DC circuitry to my external DC power source

personally, i use jumper cables when needed <grin>

you should call an application engineer at one of the reputable
manufacturers. i'm sure they would build a unit to your spec. as far as i
know, all units of this size are built to order anyway.

 

[[email protected]]

| you should call an application engineer at one of the reputable
| manufacturers. i'm sure they would build a unit to your spec. as far as i
| know, all units of this size are built to order anyway.

They are built to order from an already designed model.

 

[Spokesman]

| On 11/2/06 10:12 PM, in article [email protected],
|
|> You missed an aspect of my original quest. The power source is not AC.
|> The above mentioned units are UPSes that take AC in (DC is an intermediate
|> step). I'm looking for true inverters that take DC in, not AC. So a UPS
|> does not qualify.
|
| You should stop looking. You are in over your head. The typical UPS will do
| what you want if its rated is adequate. Just take out the battery and wire
| you dc to where the battery is connected. Then just do not use the rest of
| it.

I think not. Many UPSes do run tests and exercises on the battery inside
to check its charge level and charge acceptance quality. External batteries
could easily confuse them unless there is attached circuitry. It is NOT a
trivial, or even safe, procedure to connect a UPS to external batteries it
was not designed for.

A plain inverter works different than a UPS, too. A UPS expects a narrow
battery voltage range whereas many inverters operate on a wider range of
voltages.

Why is it that when I and many other people ask straightforward questions,
a lot of people seem to go out of their way to answer something else?
I know the difference between an inverter and a UPS and I am looking for
an inverter.

An invertor is part of a UPS.




|------------------------------------/-------------------------------------|

 

[[email protected]]

| |> On Fri, 03 Nov 2006 18:27:41 GMT Salmon Egg <[email protected]>
| wrote:
|> | On 11/2/06 10:12 PM, in article [email protected],
|> |
|> |> You missed an aspect of my original quest. The power source is not AC.
|> |> The above mentioned units are UPSes that take AC in (DC is an
| intermediate
|> |> step). I'm looking for true inverters that take DC in, not AC. So a
| UPS
|> |> does not qualify.
|> |
|> | You should stop looking. You are in over your head. The typical UPS will
| do
|> | what you want if its rated is adequate. Just take out the battery and
| wire
|> | you dc to where the battery is connected. Then just do not use the rest
| of
|> | it.
|>
|> I think not. Many UPSes do run tests and exercises on the battery inside
|> to check its charge level and charge acceptance quality. External
| batteries
|> could easily confuse them unless there is attached circuitry. It is NOT a
|> trivial, or even safe, procedure to connect a UPS to external batteries it
|> was not designed for.
|>
|> A plain inverter works different than a UPS, too. A UPS expects a narrow
|> battery voltage range whereas many inverters operate on a wider range of
|> voltages.
|>
|> Why is it that when I and many other people ask straightforward questions,
|> a lot of people seem to go out of their way to answer something else?
|> I know the difference between an inverter and a UPS and I am looking for
|> an inverter.
|
| An invertor is part of a UPS.

A UPS includes an inverter. But I am looking for a inverter that stands
alone by itself. You do know what an inverter is, I presume.

 

[Paul Hovnanian P.E.]

| [email protected] wrote:
|>
|> Does anyone make a large inverter? I'm exploring the idea of running
|> things entirely off-grid. So I'm exploring what all could be done with
|> various elements of solar, natural, and renewable power sources to see
|> if this might be practical and what constraints it may have when it
|> comes time to do this.
|>
|> But one limitation I have found is that inverters seem to all be on the
|> small side and with only limited ability to "stack" them. The largest
|> I have seen is 6000 watts. The largest Xantrex model (besides their
|> three phase grid tie units) is just 5500 watts. It can be "stacked"
|> up to 2 units either parallel (120 volts only) or series (120/240 volts).
|> But 11000 watts is a little on the wimpy side and you can't parallel a
|> stacked pair.
|>
|> I could just have multiple systems (probably 2 to 4). But that makes
|> more of a wiring nightmare. It would be easier to have a larger inverter.
|> And I would be more comfortable with having a single unit that does the
|> 3-wire system for 120/240 volts integrated. I have no committment on the
|> DC side voltage, but I'd like to be sure it is within the range that can
|> be handled by common circuit breakers from Square-D and Cutler-Hammer.
|>
|> The built-in charger in the Xantrex (and many other) units is also not
|> useful. For example, AC power sources might not be able to support the
|> peak demand, but I would certainly want to have them supplement batteries
|> in those cases. The goal of this is to be off-grid, not as a backup for
|> utility outage.
|>
|> Anyone know of larger single-phase inverters that are in, or can be stacked
|> to be in, the 15 to 50 kW range at 120/240 volts?
|
| At these power levels, you really might want to consider a 3-phase
| distribution system.
|
| The economics of 3 vs single phase is probably what dictates the 5 kW
| upper end on the latter.

Which 3 phase configuration would you suggest? Will it give me both 120
volts and 240 volts? (208 volts is not good enough because most things
for homes that need more than 120 volts need 240, not 208).

A previous post had a whole list of them. Most of the 3-phase units are
120/208, but many 120/240V appliances will work on 208.

If what you have is a bunch of smaller loads, you might be better off
splitting them up and running a group of smaller inverters. If you
really have large individual loads, they will be more efficient running
on 3 phase than single phase.

Know of any that are not "grid tie" types?

Many of the grid-tie units also operate independently.

 

[[email protected]]

| A previous post had a whole list of them. Most of the 3-phase units are
| 120/208, but many 120/240V appliances will work on 208.

Many, but not all. I've seen things designed for 240 at best just not
work on 208, and at worst burn up.


| If what you have is a bunch of smaller loads, you might be better off
| splitting them up and running a group of smaller inverters. If you
| really have large individual loads, they will be more efficient running
| on 3 phase than single phase.

I am considering the split up. But I don't want to be splitting things
up too much. So the goal is each section would be a minimum of 60 amps
of 120/240. What I could get out of the Xantrex units is 45 amps.

How does 3 phase make larger loads more efficient? It's a lower voltage.


|> Know of any that are not "grid tie" types?
|
| Many of the grid-tie units also operate independently.

Now for single phase 120/240 (or series stackable 120).

Or a 6-phase unit.

So, is the real answer that no one makes a single phase 120/240 volt 15kw
inverter (just inverter) ... or a 7.5kw series stackable 120 volt one?

All these other ideas might be considered. But right now the quest is to
find that elusive inverter that in 1 or 2 units can get me 120/240 volts
at 15kw (60 amps).

If I do go with three phase, I'd rather have it producing 480Y/277.
Then it's a cheap set of three transformers to step it down to 120/240
in three separate single phase systems ... or a 6 phase system if I tie
it all together.

And I might just build my own. Then I can try out a pulse density loop
design.