Product Manual

Operation
18 900-0161-01-01 Rev B
GridZero
In
GridZero
mode, the Radian inverter remains grid-connected, but prioritizes the use of battery
or renewable sources to run loads. It uses only renewable energy to recharge the batteries.
The inverter tries to “zero” the grid use, drawing on AC power only when needed to supplement
stored DC sources. Note that the inverter draws up to 1 Aac regardless of the DC sources.
In a MATE3-class system display, the selectable options are
DoD Volts
and
DoD Amps
. Any
time the batteries exceed the
DoD Volts
setting by 0.8 Vdc, 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 prolong cycle life and increase
battery capacity, the rate of discharge can be limited using the
DoD Amps
setting. This item
should be set lower than the current 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 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 energy demand of all loads and possible
losses. The renewable source must also charge the batteries. The inverter does not charge the
batteries in
GridZero
mode.
BENEFITS:

This mode seamlessly blends the use of battery power and grid power. It puts renewable energy to
the most effective use without selling power to the utility grid.

GridZero
mode minimizes dependence on the grid as long as certain conditions are met.

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.

This mode utilizes the
Grid Support
settings. See page 37 for more information on this function.
NOTES:
IMPORTANT:
Setting
DoD Volts
too low will severely discharge the batteries. The battery bank may not
have sufficient reserve to provide backup in the event of a grid failure. To prevent the loss
of power, load use and the
DoD Volts
setting should be planned accordingly.

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 36 for more information on
Offset
operation. However, the behavior of
Offset
in GridZero
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 (or load demand) is too low, the renewable source will be prematurely curtailed.
The system will be unable to use the renewable energy and will then be more dependent on the grid.
The
DoD Amps
setting should be raised periodically until the renewable energy is fully utilized.