Outback Power Systems GFX Series Inverter/Charger Operators Manual - Manual (Page 22)

Operation
20
900-0114-01-00 Rev A
Note: If the MATE’s ac transfer control menu is set to gen, the charger skips both Sell and Silent, and
proceeds directly to Float stage. (It will remain in Float until a new charge cycle is required, possibly
through loss of AC power.) If ac transfer control is set to grid, the charger goes through Silent as
noted and proceeds to Float only when the batteries drop to the Refloat voltage level. (See pages 14
and 15, and the MATE manual, for more information on ac transfer control.)
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 the draw of any other DC loads), and maintains them at 100% of capacity.
Target point: Float Voltage setting. The default set point is 13.6 Vdc (in a 12-volt system).
Time limit: Float Time setting.
If the voltage exceeds the Float voltage setting (usually due to another charging source), the inverter
can sell current to the loads (or the source) in an effort to bring the voltage down to the set point.
This will reduce the inverter’s draw from the AC source.
Float Timer
This is not a separate stage of charging. On the chart, 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 Refloat voltage.)
Repeated Silent
The unit re-enters the Silent mode as it did on page 19. The unit remains on the AC source, but the
charger is inactive.
Target point: Refloat Voltage setting.
The unit will continue cycling between Float and Silent for as long as the AC source is present.
However, if excess DC power is available and the batteries rise above the Sell RE set point, the unit can
re-enter Sell and begin selling the excess as described above.
The unit can only re-enter Sell when none of the timers are active. If any of the timers have accumulated
time while in Silent, the unit will enter the highest stage with accumulated time and proceed from
that point.
Figure 5 Repeated Charging Cycles
No
Charge
Bulk
Absorption
Sell RE
AC Loss
Sell RE
Bulk
Absorption
Silent
Float
Float
Timer
Absorption Set Point
Sell RE Set Point
Float Set Point
Refloat Set Point
Voltage
Time
Rebulk Point