Three-Stage Charging - Xantrex TC1012 Owner's Manual

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 21 days, the charger will automatically restart
charging in order to refresh the batteries.
Battery Voltage
Vgas voltage
Charge
start
Figure 2-2 Three-Stage Charging Process
975-0401-01-01
Vbat = Vabs
for 1 minute
Vbat = Vgas
for 1 minute
ABS
BULK
CC
Start of
charging cycle
About Truecharge™ 2 Battery Charger
lout < 10% lrating
for 1 minute
ABS
CV
ABS CV timeout
max 5 hrs
FLOAT timeout
max 21 days
Total ABS timeout
max 8 hrs
Vbat < 12.5 V
for 15 minutes
FLOAT
Time
2–3