Outback Power Systems GS8048 manual Offset, Charging Stages Over Time1

Operation

Voltage
Absorption Set Point	Absorption
Float Set Point				Float Timer
Sell Set Point
	Offset			Offset
Re-Float Set Point		Silent	Float	Silent

Bulk

No

Charge

Time

Figure 3 Charging Stages Over Time1

Voltage

Absorption Set Point

Absorption

Float Set Point

Float

No	Bulk	No Charge
Charge

Time

Figure 4 Charging Stages Over Time1 (Generator mode)

well, even if their timers have not expired. The remaining time for the slaves will be retained in the timer for each inverter.

The Absorption timer does not reset to zero when AC power is disconnected or reconnected. It only resets to zero if it runs out, or if an external STOP BULK command is sent. The rest of the time, it retains any remaining time. It adds more time to the Absorption period whenever the batteries fall below a certain voltage. (See page 23 for more information on how the timer works.)

Offset

This is not a charging stage. The Offset function is designed to use excess battery energy to power the loads, even when an AC source is present. Offset can operate in any stage of charging, but is shown in Figure 3 to display the function when no charging stages or timers are active. This function is described more fully on page 19.

Offset is a constant-voltage mode of operation. The inverter cannot import current to charge the batteries to a target voltage, but it can export any excess current to constantly hold them at this value. The target voltage used when no other stages are active, as shown in Figure 3, is the Sell Voltage 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.

1The points where the dark blue line intersects the vertical dotted line indicate a change from one step to the next. The points where they also intersect with a horizontal dotted line indicate that the charger has switched to a new target voltage.

900-0020-01-00 Rev A 21