Sorry if these questions are too simple, but I'm a bit new at this.

1) Why do grid tie inverters shut down when the utility goes away? I understand the idea of islanding but it seems to me that one can isolate an inverter from the utility grid but allow it to continue to supply power to a house.

2) How does adding a battery to a GT inverter work? (Is this then a "hybrid" inverter?) I know the battery can supply power to the inverter for conversion to AC (and not endanger workers when the utility is down) but do the PV panels supply power to the inverter directly, for conversion to AC, or do they charge the battery only, or both?

TIA

It's a code requirement. UL 1741 IIIRC.



You cannot add a battery to a GT inverter, you need a hybrid inverter (XW6048) and a charge controller.

When the utility shuts down, what does the XW6048 do? Will it supply the household load, or just charge the batteries?

What's a good reference for an overview, including schematics showing panels, charge controllers, etc? Can't find anything on the Xantrex website.

If you are using only a XW6048 & a battery bank, it will switch over (has it's own internal transfer switch) from Pass-Through / Charge mode, and into INVERT mode. You won't even see the computer screen blink. Like a giant UPS.

Bur figure an average house is pulling/using 2Kw of power (200 amp service can supply 48Kw to a house) and the inverter can only produce 6Kw. You need to have the inverter only feed your critical loads (kegerator, the aunt's Iron Lung, coffee pot)
The batterys will last __ depending on your loads and battery bank size. You can add charging from a 240V generator (AC2 input) or from solar with a charge controller wired to the batteries

When the Grid returns, the Invert stops, and battery charge (from the grid) resumes

Is this correct?

1) When the utility is up, the XW6048 acts like a grid tie inverter, including net metering.
2) When the utility goes down, the XW6048 draws from the batteries only, not from the PV panels.
3) The batteries can be charged simultaneously from the PV panels and(?)/or from a generator.

Is this correct?

1) When the utility is up, the XW6048 acts like a grid tie inverter, including net metering.
2) When the utility goes down, the XW6048 draws from the batteries only, not from the PV panels.
3) The batteries can be charged simultaneously from the PV panels and(?)/or from a generator.

Yep, you've got it.