Posted by sspence on May 3, 2010, 3:17 pm
> Well the idea of grid tie (called net metering) is that you don't need
> batteries. The grid acts as a battery. This is what is attractive to me, I
> would not need batteries. And I like that because batteries are expensive
> and don't last forever.
> I think Xantrex makes one that will also work off-grid? Then you could use a
> battery charger I would assume...
> Xantrex which now seems to be "Schneider"...http://www.schneider-electric.com/corporate/en/products-services/rene ...
> Then there are plenty of 120 volt AC or 240 volt AC battery chargers.
> And you can get a transfer switch for the generator.
> "David Lesher" wrote in message
> > I'm looking for make/models of inverter systems that can work in
> > two different cases:
> > a) Grid-tie; when excess PV output is sold back to the utility.
> > b) Offline backup: When the grid's dead; you draw down on
> > battery backup, and/or generator.
> > While some folks talk about doing both in one box, it appears
> > both regulatory and technology issues generally preclude same,
> > at least in the 15KW/3ph. and up PV range.
> > Further, we want to take advantage of the PV capacity
> > whenever. In other words, in b) mode, we want the PV output to
> > supply loads, including battery recharge. Most of the vendors
> > I've looked at fall down in that regard.
> > (At first, I thought it could be done at the DC level, but no
> > joy there; the grid-tie inverters want DC strings in the hundreds
> > of volts; the stand-alone ones are expecting 48V or other lower
> > voltage DC inputs.)
> > Sunny/aka SMA tells me they can not only recharge the battery
> > plant from the PV inverter, but if the array can't keep up; it
> > will request a generator start and all three 60 Hz. sources will
> > play, in tune as needed.
> > So my questions:
> > 1) Has anyone here used such a system?
> > 2) Know of any other venders of such cooperative systems?
Using the grid as your battery doesn't help you when th grid is down.
We went 30 days with no grid in the Ice Storm of '98.
Posted by z on May 3, 2010, 4:13 pm
>> Well the idea of grid tie (called net metering) is that you don't
>> need batteries. The grid acts as a battery. This is what is
>> attractive to me,
> I
>> would not need batteries. And I like that because batteries are
>> expensive and don't last forever.
>>
>> I think Xantrex makes one that will also work off-grid? Then you
>> could us
> e a
>> battery charger I would assume...
>>
>> Xantrex which now seems to be
>> "Schneider"...http://www.schneider-electric
> .com/corporate/en/products-services/rene...
>>
>> Then there are plenty of 120 volt AC or 240 volt AC battery chargers.
>>
>> And you can get a transfer switch for the generator.
>>
>>
>>
>> "David Lesher" wrote in message
>> > I'm looking for make/models of inverter systems that can work in
>> > two different cases:
>>
>> > a) Grid-tie; when excess PV output is sold back to the utility.
>>
>> > b) Offline backup: When the grid's dead; you draw down on
>> > battery backup, and/or generator.
>>
>> > While some folks talk about doing both in one box, it appears
>> > both regulatory and technology issues generally preclude same,
>> > at least in the 15KW/3ph. and up PV range.
>>
>> > Further, we want to take advantage of the PV capacity
>> > whenever. In other words, in b) mode, we want the PV output to
>> > supply loads, including battery recharge. Most of the vendors
>> > I've looked at fall down in that regard.
>>
>> > (At first, I thought it could be done at the DC level, but no
>> > joy there; the grid-tie inverters want DC strings in the hundreds
>> > of volts; the stand-alone ones are expecting 48V or other lower
>> > voltage DC inputs.)
>>
>> > Sunny/aka SMA tells me they can not only recharge the battery
>> > plant from the PV inverter, but if the array can't keep up; it
>> > will request a generator start and all three 60 Hz. sources will
>> > play, in tune as needed.
>>
>> > So my questions:
>>
>> > 1) Has anyone here used such a system?
>> > 2) Know of any other venders of such cooperative systems?
>
> Using the grid as your battery doesn't help you when th grid is down.
> We went 30 days with no grid in the Ice Storm of '98.
>
Yeah I think a lot of people are looking to grid tie (probably for tax
reasons .. and to get the 5 cents/kwh or whatnot) but also have the
batteries for when the grid is down.
It's best of both worlds if you can afford it.
Posted by David Lesher on May 4, 2010, 1:06 am
>Using the grid as your battery doesn't help you when th grid is down.
>We went 30 days with no grid in the Ice Storm of '98.
Bingo. We'll have a propane generator, but it's big, noisy and $$$$ to run
for long.
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
Posted by Josepi on May 3, 2010, 5:55 pm
I think the OP is looking for battery backup as a prerequisite spec.
I have a unit all-in-one unit that does all that but only a 3kW unit with
peak cap of 10kW for 120 seconds.
Well the idea of grid tie (called net metering) is that you don't need
batteries. The grid acts as a battery. This is what is attractive to me, I
would not need batteries. And I like that because batteries are expensive
and don't last forever.
I think Xantrex makes one that will also work off-grid? Then you could use a
battery charger I would assume...
Xantrex which now seems to be "Schneider"...
http://www.schneider-electric.com/corporate/en/products-services/renewable-energies/renewable-energies-intermediate.page?q=NNM1:Solar+Grid+Tie+Systems&f3%3ARenewable+Energies&p_function_id 210
Then there are plenty of 120 volt AC or 240 volt AC battery chargers.
And you can get a transfer switch for the generator.
"David Lesher" wrote in message
> I'm looking for make/models of inverter systems that can work in
> two different cases:
> a) Grid-tie; when excess PV output is sold back to the utility.
> b) Offline backup: When the grid's dead; you draw down on
> battery backup, and/or generator.
> While some folks talk about doing both in one box, it appears
> both regulatory and technology issues generally preclude same,
> at least in the 15KW/3ph. and up PV range.
> Further, we want to take advantage of the PV capacity
> whenever. In other words, in b) mode, we want the PV output to
> supply loads, including battery recharge. Most of the vendors
> I've looked at fall down in that regard.
> (At first, I thought it could be done at the DC level, but no
> joy there; the grid-tie inverters want DC strings in the hundreds
> of volts; the stand-alone ones are expecting 48V or other lower
> voltage DC inputs.)
> Sunny/aka SMA tells me they can not only recharge the battery
> plant from the PV inverter, but if the array can't keep up; it
> will request a generator start and all three 60 Hz. sources will
> play, in tune as needed.
> So my questions:
> 1) Has anyone here used such a system?
> 2) Know of any other venders of such cooperative systems?
Posted by David Lesher on May 4, 2010, 1:04 am
>Well the idea of grid tie (called net metering) is that you don't need
>batteries. The grid acts as a battery. This is what is attractive to me, I
>would not need batteries. And I like that because batteries are expensive
>and don't last forever.
And when the grid fails?
>I think Xantrex makes one that will also work off-grid? Then
>you could use a battery charger I would assume...
>Xantrex which now seems to be "Schneider"...
>Then there are plenty of 120 volt AC or 240 volt AC battery chargers.
>And you can get a transfer switch for the generator.
If only it were that simple. One big goal is: use solar power
when both on and off grid. I've seen several schemes that just
shut down the PV input when offgrid.
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
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> batteries. The grid acts as a battery. This is what is attractive to me, I
> would not need batteries. And I like that because batteries are expensive
> and don't last forever.
> I think Xantrex makes one that will also work off-grid? Then you could use a
> battery charger I would assume...
> Xantrex which now seems to be "Schneider"...http://www.schneider-electric.com/corporate/en/products-services/rene ...
> Then there are plenty of 120 volt AC or 240 volt AC battery chargers.
> And you can get a transfer switch for the generator.
> "David Lesher" wrote in message
> > I'm looking for make/models of inverter systems that can work in
> > two different cases:
> > a) Grid-tie; when excess PV output is sold back to the utility.
> > b) Offline backup: When the grid's dead; you draw down on
> > battery backup, and/or generator.
> > While some folks talk about doing both in one box, it appears
> > both regulatory and technology issues generally preclude same,
> > at least in the 15KW/3ph. and up PV range.
> > Further, we want to take advantage of the PV capacity
> > whenever. In other words, in b) mode, we want the PV output to
> > supply loads, including battery recharge. Most of the vendors
> > I've looked at fall down in that regard.
> > (At first, I thought it could be done at the DC level, but no
> > joy there; the grid-tie inverters want DC strings in the hundreds
> > of volts; the stand-alone ones are expecting 48V or other lower
> > voltage DC inputs.)
> > Sunny/aka SMA tells me they can not only recharge the battery
> > plant from the PV inverter, but if the array can't keep up; it
> > will request a generator start and all three 60 Hz. sources will
> > play, in tune as needed.
> > So my questions:
> > 1) Has anyone here used such a system?
> > 2) Know of any other venders of such cooperative systems?