D
David Lesher
- Jan 1, 1970
- 0
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?
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?