9
CHARGING CYCLE
MULTI US 3300 operates in a three step fully automatic cycle IUoUp. 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 0.4 A, the charger switches to
pulse maintenance. If the battery is charged and the terminal voltage of the battery falls to
12.9 V, the charger automatically starts again at the first step of the charge characteristic.
The MULTI US 3300 measures both voltage and current in order to determine out whether
the charging process is finished or whether a new charging cycle must be started. Various
methods are used, depending on the time of the measurement; see table:
When?
Reading
Yes
No
Before the start or
after changing the
charging mode.
Voltage higher than
12.9 V?
Green indicator lit
until the voltage
< 12.9 V.
Orange indicator,
charging process.
During the charging
process.
Current greater than
0.4 A?
Orange indicator,
charging process.
Green indicator
illuminated until the
voltage < 12.9 V.
Time
Vo
ltage/Current
Current
Voltage
Absorption
Uo
Pulse
Up
Bulk
Io
Bulk:
Charging where about 80% of the energy is returned. The charger delivers an
almost constant current until the battery voltage reaches the set level.
Absorption:
Charging up to almost 100%. The charge current tapers and the voltage is
kept constant at the set level.
Pulse:
Maintenance charge. The charging process ranges between 95 % and 100 %.
The battery receives a pulse if the voltage falls. This stage will keep your battery in a good
condition if it is not being used.
