Outback Power Systems GS4048A Operators Manual - Manual (Page 20)

Operation
18 900-0161-01-00 Rev A
Mini Grid
In Mini Grid mode, the Radian 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 Radian 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 Table 16 on page 65.
While connected to the utility grid, the inverter’s 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 float stage, the
inverter will disconnect from the grid.
If the inverter is connected to the utility grid and the charger is turned off, another DC source such as
renewable energy should be present to charge the batteries. The inverter will observe the batteries as
if it was performing the charge. When the batteries reach the required voltages and charging times to
achieve float stage, the inverter will disconnect from the grid. This means that the regulator for the
renewable source must be set to the same settings as the Radian (or higher). Check the settings of
both devices as needed.
See page 27 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 Radian inverter will offset the loads with excess renewable energy if it is available from the batteries.
See page 35 for more information on Offset operation. However, the Offset function is inapplicable when
the Radian 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 the MATE3 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 Grid Use Time and Load Grid Transfer functions of the MATE3
system display. These functions do not have similar priorities to
Mini Grid or HBX, but they do control the
inverter’s connection and disconnection with the grid. Mini Grid should not be used with these functions.
 When deciding whether to use Mini Grid mode or HBX, the user should consider the aspects of each.
∼ Mini Grid logic is based in the Radian inverter and can function in the absence of the MATE3. HBX logic
is based in the MATE3 and cannot function unless the MATE3 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 intended to protect the batteries
from excessive discharge; however, most of its 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 source is larger than the size of the loads. If this
condition is not met, Mini Grid will not disconnect the inverter from the utility grid.