Operation

About Charging

The XC Series has three full current rated, independently controlled outputs which enable it to charge three different batteries or battery banks. Each output can accommodate any one of the four allowable battery types, regardless of what battery types are connected to the other outputs. Each output can be in a different stage of charge, ralative to the other banks; for exampe, Bank 1 in float, Bank 2 in absorption and Bank 3 in bulk. Each bank can accommodate a separate battery temperature sensor. The XC Series can also perform either multiplex (3 stage) charging, or sequential (2 stage) charging.

Important: The battery banks are not galvanically isolated from each other. They share a common negative.

Multiplex 3-Stage Charging

In multiplex charging mode the charger will check all qualified battery banks every 15 seconds to determine which bank is most in need of charging. That bank will then be charged for the next 15 seconds. Every 15 minutes the charger will query all outputs and detect which battery banks are present and healthy.

The multiplex charging mode employs the 3-stage charging algorithm: Bulk,

Absorption, and Float. During the Bulk stage the battery is accepting high current.

In the Absorption stage the battery voltage is held constant and the current declines.

A battery will also "gas" (produce hydrogen and oxygen) during this stage. Finally,

in the Float stage, the charger continues to provide voltage at a lower level to

maintain the battery in a fully charged state. If there is no load on the battery, it will

typically draw very little current. The charger, however, is able to provide current to

its full rating to power DC loads on the battery. In float, if batteries are very new or

a battery is on the low end of the size range and if it is fully charged to the point

where it will not accept any more current, then the charger will enter an adaptive

float/no float behaviour where it will alternate between float charging (

) and

resting the battery ( ).

 

The charger will restart the charging cycle in the Bulk stage if the battery voltage

 

drops below 12.5 V (12 V units) or 25 V (24 V units) for 15 minutes. After 21 days,

 

the charger will automatically restart charging in order to refresh the batteries.

3–2

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Xantrex Technology XC5012, XC2524, XC3012, XC1524 manual About Charging, Multiplex 3-Stage Charging