Grid zero, Operation – Outback Power Systems GS4048A Operators Manual User Manual
Page 21
Operation
19
∼ HBX can be combined with the settings of any other input mode (Generator, UPS, etc.). The Mini Grid
input mode is limited to its own settings and does not have access to certain functions of other modes.
∼ See page 45 for more information on HBX, Grid Use Time, and Load Grid Transfer.
Grid Zero
In
Grid Zero mode, the Radian inverter runs primarily from battery (and renewable) energy while
remaining connected to an AC source. The inverter only draws on the AC source (usually the utility
grid) when no other energy is available. Using the DC sources, the inverter attempts to decrease the
use of the AC source to zero.
In the MATE3 system display, the selectable options are
DoD Volts and DoD Amps. Any time the
batteries exceed the
DoD Volts setting, the Radian will send power from the batteries to the loads. As
the battery voltage decreases to the
DoD Volts setting, the inverter will reduce the rate of flow toward
zero. It will maintain the batteries at this setting.
The Radian inverter can manage large quantities of power. To prevent damage to the batteries from
rapid discharge, the rate of discharge can be limited using the
DoD Amps setting. This item should be
set lower than the amperage provided by the renewable source.
When
DoD Volts is set low, this mode allows more renewable energy to be delivered from the batteries to
the loads. However, it will also leave less of a battery reserve in the event of a grid failure.
When
DoD Volts is set high, the batteries will not be discharged as deeply and will retain more of a backup
reserve. However, not as much renewable energy will be sent to the loads.
The renewable energy source needs to exceed the size of the loads after accounting for all possible
losses. The renewable source is also required to charge the batteries after this mode discharges them.
The inverter’s battery charger does not function in
Grid Zero mode.
BENEFITS:
Grid Zero mode allows a system to minimize or eliminate dependence on the utility grid. This is only
possible if certain conditions are met. See the Notes section.
This mode puts battery and renewable energy to the most effective use without selling power to the utility
grid and without dependence on the grid.
The inverter remains connected to the utility grid in case the grid is needed. If large loads require the use of
grid power, no transfer is necessary to support the loads.
NOTES
:
If the renewable energy source is not greater than the size of the inverter loads, this mode will not work well
over time. The renewable source must be capable of charging the batteries as well as running the loads.
This occurs when renewable energy production exceeds the
DoD Amps setting.
The 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 behavior of Offset in Grid Zero mode is
different because it uses the
DoD Volts exclusively.
The inverter’s battery charger cannot be used in this mode. However, the charger menu settings and timer
operations are not changed when this mode is selected.
The battery should be discharged whenever possible in the attempt to “zero” the grid usage. If the
DoD
Amps setting is limited or loads are not present, the batteries will be unable to accept much renewable
recharging the next time it is available. The renewable energy will be wasted, leaving the system
dependent on the utility grid more than necessary.