Xantrex Technology TC2 204060 manual Three-Stage Charging

TC2 204060 Series BattChg Owners Guide.book Page 29 Friday, July 8, 2011 11:44 AM

Installing Batteries

Three-Stage Charging

The three-stage charging mode employs the following sequence: Bulk, Absorption, and Float. During the Bulk stage the batteries are accepting a constant maximum current. In the Absorption stage, the battery voltage is held constant and the current declines. A battery will “gas” (produce hydrogen and oxygen) when its voltage exceeds the “gassing” voltage. 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 auxiliary DC loads on the battery.

The charger will restart the charging cycle in the Bulk stage if the lowest battery voltage of the three banks drops below 12.5 V (12 Vdc chargers) or 25 V (24 Vdc chargers) for 15 minutes. After seven days, the charger will automatically restart charging in order to refresh the batteries.

Vbat = Vabs	lout < 10% lrating
for 1 minute	for 1 minute
Battery Voltage
Vbat = Vgas	Vbat < 12.5 V
for 1 minute	for 15 minutes

Vgas voltage
Charge
start
BULK	ABS	ABS	FLOAT
	CC	CV
		ABS CV timeout	Time

max 5 hrs

Start of		FLOAT timeout
		max 7 days
charging cycle
	Total ABS timeout
	max 8 hrs

Figure 9 Three-Stage Charging Process

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