Xantrex Technology 815-3012, 815-3024 manual Battery Charging Reference, Bulk Stage, 97-0019-01-01

Freedom SW 3K2K InvChg Owners Guide.book Page 59 Wednesday, October 9, 2013 1:34 PM

Battery Charging Reference

The charging cycle is a multi-stage (three-stage) process. Whenever qualified AC power is present at the inverter’s input, it passes power through to the connected load and begins charging the batteries.

Bulk Stage	Absorption Stage	Float Stage
Battery
Voltage
	Absorption Voltage
	3-Stage Charge	Float Voltage
		Time

Max Absorb Time - Dflt 3 hrs (adjustable 1 min - 8 hrs)

Battery

Current

Max Charge

Rate

Absorption Exit Current

Threshold = 2% of programmed AH capacity

NOTE:

When the charge cycle is interrupted, the charger will restart charging at the beginning of the multi-stage algorithm.

Exit Current Threshold can be effectively disabled by programming the amp-hour capacity to the minimum. In this case, absorption will only exit once the Max Absorption timer expires.

Charge current during equalize state (optional state not shown here) is normally limited to 10% of the programmed amp-hour capacity setting. If this setting is programmed to the maximum, the charge current during equalize is instead limited to whatever is programmed for the maximum current limit of the unit.

Synchronized charge states are active when more than one charging device is connected in the system via the Xanbus network.

•The first unit (Freedom SW) to enter bulk, causes all other chargers to enter bulk.

•The first Freedom SW to enter absorption causes all other Freedom SWs to enter absorption.

•The last Freedom SW ready to exit absorption triggers all Freedom SWs to exit absorption and exit charge.

Bulk Stage

Time

Figure 32 Three-Stage Battery Charging Cycle

Bulk charge is the first stage in the charging process and provides the batteries with a controlled, constant current. Once the battery voltage rises to the absorption voltage threshold, the charger switches to the absorption stage.

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