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How Do I Set My XW+ / MPPT To Charge Based on Absorption Time Only?

Issue
Need to configure the charger on the inverter or charger controller to be based only on time.

Product Line
MPPT60, MPPT80, XW, XW+, CSW

Environment
Inverter and/or charge controller used in a situation where Absorb Time needs to be fixed.

Cause
There may be times where a fixed Absorption Time is preferred over current controlled Absorb Time.  Normally, the XW and MPPTs will end Absorption when the charging amps drops to 2% of the set capacity for 1 minute or when the time is Absorption reached the setting for Absorb Time.  If the batteries seem to be short charging due to a condition such as sulfation, then using a fixed Absorb Time may help burn off some of the sulfation in the batteries.  This should not be confused with having shorted cells, as that will not be recoverable using this method.

In the Conext SW and legacy XW with older firmware, it is not possible to set the capacity to 0Ah.  Instead, setting to battery capacity to 50A will force those inverters to only stop absorption when the charging amperage is 1A or lower for 1 minute.  This may still be enough to complete an Absorption using the length of the Absorb Time setting.  For a legacy XW, it would be preferable to upgrade the firmware to revision 1.07.

Resolution
By setting the Battery Capacity to 0Ah, the inverter and/or charge controller is forced to use only the Absorb Time to determine when Absorption will end.  The battery manufacturer should be consulted for a recommended length of absorption as well as charging threshold prior to commissioning the system.
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