Outback Power Systems GS8048 Operator Manual - Manual (Page 24)

Operation
22 900-0020-01-00 Rev B
setting. (Excess current typically comes into the batteries from a PV array, wind turbine, or similar
renewable energy source.)
Target point: Sell Voltage setting. The default setting is 52.0 Vdc.
This setting is typically lower than the Float voltage setting. Although the batteries are not
discharged, they are maintained at a somewhat lower voltage so that the maximum amount of power
can be exported. It is recommended that this item be set at the batteries’ natural rest voltage.
In the
Grid Tied input mode, excess power is sent first to any loads on the inverter’s output, using the
Offset function (see page 19). If the exported power exceeds the load requirements, the excess is sold
back to the utility grid, using the inverter’s AC input terminals. The unit will maintain this activity for
as long as excess power is available. See page 11 for more notes on the
Grid Tied input mode.
Regardless of the input mode setting, if no renewable energy is present, the inverter will exit (or skip)
this step and enter Silent.
Silent
This is not a charging stage, but a quiescent period between stages. The inverter remains on the AC
source, but the charger is inactive. It enters this condition upon completing the Absorption stage and
concluding (or skipping) Offset operation.
In Silent, the batteries are not in significant use by the inverter, but they are also not being charged.
The battery voltage will naturally decrease when not maintained by another means such as a
renewable source.
The term “Silent” is also used in the context of stacking inverters and Power Save levels. See page 27.
Target point: Re-Float Voltage setting. When the battery voltage decreases to this point, the
charger becomes active again. The default set point is 50.0 Vdc.
NOTE: If the Radian inverter is placed in the Generator input mode, the charger skips Silent and
proceeds directly to Float stage (see Figure 4 on page 21). It will remain in Float until AC power is
disconnected, which usually means that the generator was stopped manually or automatically.
See page 9 for more information on this mode.
Float Stage
This is the third stage of charging. It is a constant-voltage stage. Current varies as needed to maintain
the voltage, but typically drops to a low number. This stage offsets the batteries’ tendency to
self-discharge (as well as offsetting the draw of any other DC loads), and maintains them at 100% of
capacity.
Target point: Float Voltage setting. The default set point is 54.4 Vdc.
Time limit: Float Time setting.
NOTE: The remaining stages below do not apply in the Generator input mode. The next activity that
can occur is a new charging cycle. The criteria for beginning a new cycle are described on page 23.
Float Timer
This is part of Float stage and is not a separate stage of charging. On the charts on page 21, it is
marked as a separate step to note that the timer only begins running upon reaching the Float set
point. It does
not begin running at the beginning of Float stage. (The Float timer is reset to its
maximum amount whenever the batteries drop to the Re-Float voltage.)