Outback FX-R Series Operator Manual

Operation
900-0167-01-01 Rev A 19
Mini Grid
In
Mini Grid
mode, the FXR inverter automatically rejects an AC source and runs solely from
battery (and renewable) energy. The inverter only connects to the AC source (usually the utility
grid) when the batteries run too low.
The inverter runs on battery-supplied power for as long as the batteries can be sustained. It is
expected that the batteries will also be charged from renewable sources such as PV. When the
batteries become depleted, the system reconnects to the utility grid to operate the loads.
The inverter will reconnect to the utility grid if the battery voltage decreases to the
Connect to
Grid
set point and remains there for the
Delay
time period. These items are shown in the tables
which begin on page 66.
While connected to the utility grid, the FXR charger can be set either On or Off. If the charger is
turned on, the inverter will proceed through a full charging cycle. Upon reaching the end of the
charging cycle, the inverter will disconnect from the grid.
If the inverter is connected to the utility grid and the charger is turned off, another source such as
renewable energy should be present to charge the batteries. The inverter will observe the
batteries as if it was charging. When the batteries reach the required voltage and time to end the
cycle, the inverter will disconnect from the grid. This means that the renewable source regulator
settings must be the same as the inverter (or higher). Check both settings as needed.
See page 29 for more information on the battery charging cycle.
BENEFITS
:

Mini Grid
mode allows a system to minimize or eliminate dependence on the utility grid. This is only
possible if certain conditions are met. See below.
NOTES
:
 The inverter will offset the loads with excess renewable energy if it is available from the batteries. See
page 38 for more information on Offset operation. However, Offset is inapplicable when the inverter
disconnects from an AC source. The renewable energy supports the inverting function instead.

This mode has similar priorities to the high-battery transfer (
HBX
) function used by a MATE3-class
system display. However, it is not compatible with
HBX
and cannot be used at the same time. When
using
Mini Grid
mode, the system display should disable
HBX
to prevent conflicts.
Mini Grid
mode is also incompatible with the system display
Grid Use Time
and
Load Grid Transfer
functions. These functions do not have similar priorities to
Mini Grid
or
HBX
, but they do control the
inverter’s grid connection and disconnection.
Mini Grid
should not be used with these functions.

When deciding whether to use
Mini Grid
mode or
HBX
, the user should consider aspects of each.
 Mini Grid logic is based in the FXR inverter. After programming, it can function in the absence of the system
display. HBX logic is based in the system display. It cannot function unless the system display is installed
and operating.
 Mini Grid can use utility grid power to fully recharge the batteries every time it reconnects to the grid.
HBX can only do so under specific circumstances.
 HBX set points have a wide range of settings. Mini Grid uses settings which protect the batteries from
excessive discharge; however, most settings are automatic and do not allow customization.
HBX works more efficiently with a larger renewable source, but there is no specification for renewable size.
Mini Grid cannot work properly unless the renewable source is larger than the loads. If this condition is not
met, Mini Grid will not disconnect the inverter from the utility grid.
 Mini Grid is one of seven inverter-level functions (modes) which share a single input. Selecting it prevents
any other input mode from being used. HBX is a system-level function which can be combined with the
settings of other input modes.
 See the system display literature for more information on HBX mode, Grid Use Time, and
Load Grid Transfer.