Charging Cycle - CTEK MULTI US 3300 User Manual

time until the required mode is reached, the button is then released. The selected mode is
saved in a memory in the charger and remains there even if the charger is switched off.
Mode 14.4V/0.8A
This mode is normally used for batteries <14Ah.
Mode 14.4V/3.3A
Normal setting for wet batteries, maintenance free and for most Gel batteries.
Some gel batteries prefer a slightly lower voltage. Please consult the battery
manufacturer when in doubt.
Mode 14.7V/3.3A
This setting is recommended for a battery at temperatures <41°F. It is also
recommended for many AGM batteries like Optima, Maxxima and Odysses.
Consult your battery manufacturer when in doubt.

CHARGING CYCLE

MULTI US 3300 operates in a four step fully automatic cycle. It starts the charging with
an almost constant current (0.8A or 3.3A) until maximum voltage (14.4V or 14.7V) is
reached. At this point the charger switches to constant voltage, and the current supply
to the battery is gradually reduced. If the current drops to 0.4A, the charger switches to
pulse maintenance. If the battery is charged and the terminal voltage of the battery falls to
The MULTI US 3300 measures both voltage and current in order to determine out whether
methods are used, depending on the time of the measurement; see table:
When?
Before the start or
after changing the
charging mode.
During the charging
process.
Reading Yes
Voltage higher than Green indicator lit
12.9V? until the voltage
<12.9V.
Current greater than Orange indicator,
0.4A? charging process.
No
Orange indicator,
charging process.
Green indicator
illuminated until the
voltage <12.9V.
US • 9