Xantrex Truecharge 20+ Amp Owner's Manual - page 59
Charging Algorithms
B–3
Bulk Charge
In the first stage, known as the bulk charge, Truecharge+ delivers its full-
rated output current.This constant current is delivered to the batteries until
the battery voltage approaches its absorption voltage—typically around
14.4 volts for 12 volt batteries. The bulk charge stage restores about 75%
of the battery’s charge.
Absorption
Charge
During the absorption charge, the charging voltage is held constant near
the gassing voltage, and the battery gradually reduces the charging current
it demands as it attains full charge. Once the current drops below 4 Adc
for three minutes, the charger either exits to Float for gel and AGM
batteries or charges flooded batteries for one more hour.
This extended one-hour charge ensures that the batteries are fully topped
up and is recommended by the flooded battery manufacturers.
Float Charge
The float charge is a maintenance mode in which the output voltage of the
charger is reduced to a lower level, typically about 13.5 volts to maintain
the battery’s charge without losing electrolyte through gassing. Unlike
many standalone chargers, Truecharge+ can be left connected to your
battery indefinitely without risk of overcharging.
In the float mode, the charger will initiate a new charge cycle under any of
these conditions:
•
AC power is disconnected and reconnected
•
any battery drops below 12.5 VDC for 15 minutes
•
21 days have passed from the time the charger completed Absorption.
The chart in
shows the three-stage charging profile.