How does the inverter rating work?

foolios

For example;
the OUTBACK POWER VENTED VFXR3524A 3500W 24VDC HYBRID SERIES SINE WAVE INVERTER

I do not understand how the amount of wattage passing through the inverter is controlled. 
Is the A/C output connected to a breaker in the main panel or does it have to be wired to a subpanel/alternate load box/transfer switch?

If it can be connected to a breaker in the main panel;
I would guess then all the rating is saying is, is that this is the maximum amount of watts you should size your installation for because this is all that the inverter will provide. The control of max power is done and handled by the inverter.
This seems to suggest that all the power created by the solar system will be used by any load in the main panel with any extra wattage then exported out to the grid.

If it has to be connected to a separate load box;
I would guess this would mean that I have to make sure that the loads are not going to require more than the rated wattage of the inverter.
But in this scenario, how does the excess power created by the solar/battery system get into the grid?

Which scenario is the correct one? I am hoping that this GTI can be connected to the main panel.

Thanks in advance for any explanations.

foolios

I think, I realize what is happening with the rating. It's that this device has the battery backup ability. So just like any inverter, it is going to have a max load capability to provide the backup power to the particular loads which have to stay within the inverter's rating. So it appears that any extra generation will still go into the grid so long as at least one of those subpanel breakers are closed. Correct?
But this seems to mean that you must be careful to size each breaker in the subpanel. Not only is it going to provide load but it also has to be able to handle the extra power feeding into the grid. 
How do you size the breaker for the load and the possible feedback safely?

BB.

A "pure" GT solar inverter... Just connects to the main panel. And as you say, the power either goes local and any "extra" goes backwards through the power meter (for all the world, the Utility looks like a "giant AC battery bank" and your discharging/charging the AC utility "battery").

For a Hybrid system... The GT mode is the same thing (more or less--your local battery gets "priority" for recharging first).

However, you do need a second "sub panel" where you would wire up your "protected circuits" (those circuits that get AC power when the grid "goes down"). Anything in your main AC panel will not be "battery backed" AC power from your inverter (unless you want all AC circuits to run from your AC hybrid inverter during a power failure).

-Bill

Raj174

Hi foolios,

I have the Radian GS4048A which has the same functionality modes as the VFXR3524 but it's a little bigger, is 48 volt DC and 240 volt AC. This is how it's connected. A breaker on the main panel feeds an epanel and the inverter AC input. The epanel has a bypass switch that connects power to the sub panel or connects the inverter output to the sub panel. The inverter can back feed (sell to) the grid through it's supply breaker in the main panel or blend grid power with solar/battery production to supply larger loads or surges than the inverter could handle alone (Grid Zero mode).  It also can work as if off grid in (Mini Grid mode).

Rick

foolios

Thank you. Those explanations make it much clearer.