Outback Power Systems GS8048 manual Battery Charging, Charging Steps, No Charging, Bulk Stage

Operation

Battery Charging

IMPORTANT:

Battery charger settings need to be correct for a given battery type. Always follow battery manufacturer recommendations. Making incorrect settings, or leaving them at factory default settings, may cause the batteries to be undercharged or overcharged.

The inverter uses a “three-stage” battery charging process. The three stages are Bulk, Absorption, and Float. These stages follow a series of steps, which are shown on graphs (see page 21).

NOTES:

The process shown in Figure 3 also includes the step of selling power back to the utility, as this is integrally tied with the battery charger. This step, and Figure 3, are only applicable when the Radian inverter is in the Grid Tied input mode.

The process shown in Figure 4 eliminates Silent, Float Timer, and other parts of the process. Figure 4 is only applicable when the Radian inverter is in the Generator input mode.

The target points and time limits cited under various steps are also used by the inverter’s Offset function. (See page 19.) These items are settable using the MATE3 system display. (See the MATE3 Owner’s Manual.)

Charging Steps

No Charging

If the inverter is not charging, any of the following conditions may apply:

The unit is inverting or not connected to a qualified AC source.

The unit is connected to an AC source but is in a mode or stage that does not use the charger. (Silent mode is one example.)

The unit is connected to an AC source but the charger has been turned off.

Bulk Stage

This stage activates the charger. This is the first stage in the three-stage charge cycle. It is a constant-current stage which drives the battery voltage up. This stage typically leaves the batteries at 75% – 90% of their capacity, depending on conditions.

Target point: Absorb Voltage setting. The default setting is 57.6 Vdc.

The initial DC current is the maximum current the charger can deliver. It will begin at the charger’s specified maximum, but will gradually decrease as the voltage increases. This is a tradeoff in wattage and is normal for the charger.

Absorption Stage

This is the second stage of charging. It is a constant-voltage stage. Current varies as needed to maintain the voltage, but will typically decrease to a very low number over time. This “tops off the tank”, leaving the batteries at essentially 100% of capacity.

Target point: Absorb Voltage setting.

Time limit: Absorb Time setting. This timer counts down from the inception of the Absorption stage until it reaches zero. The timer can be viewed. (See the MATE3 manual.)

For multiple inverters only:

The charging of multiple stacked inverters is synchronized and is governed by the master. When the master inverter reaches the end of Absorption (and other stages), the slaves will exit Absorption as

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