Sharp VL-E39S Service Manual page 65

2 minutes.
Since this period is provided to activate the battery, the
completion of charging is not detected. Only the battery
protection functions such as overvoltage detection, ab-
normal temperafure detection, etc. are available here.
The next operation is the initial charging as in case of Nl-
Cd battery.
Differing from the Nl-Cd battery, the limit voltage of the
overvoltage detection is 5.1V and an abnormal tempera-
ture detection function is provided.
The third stage is the quick charging mode; which is
equivalent to the quick charging of the Ni-Cd battery.
The phenomenon detection function in this mode and
the mode shift due to detection are as follows:
I)
-~
V detection
If battery voltage
-~V
(22 to 62mV) is detected,
the mode is switched to the trickle charge mode.
II)
Overvoltage detection
Excess of battery voltage over 5.1V is judged to
be abnormal, and the mode is switched to the
trickle charge mode.
III)
~
T detection
If the gradient of temperature rise of the charging
battery exceeds 1°C/min., it is judged that the
charging is completed soon and the mode is
switched to the sub-charging mode.
IV) Abnormal temperature detection
If the battery temperature reaches 60°C to 65°C
during charging, charging is stopped to protect
the battery, and the mode is switched to the
trickle charging mode.
V) Timer operation
When 180 minutes elapse after start of quick
charging, the mode is switched to the SUb-charg-
ing mode.
In the sub-charging mode which is set due to
~
T detec-
tion and timer operation in the quick charging mode,
constant current (about 0.5A) charging is performed as
with the pre-charging mode.
At this time, the mode is switched by
-~
V detection
function, overvoltage detection function and abnormal
temperature detection function as in case of quick
charging. But the mode is switched to the sub-charging
mode by the built-in timer when one hour elapses after
the pre-charging is started.
As with the Ni-Cd battery, the trickle charging current is
supplied at the constant voltage and fixed resistance in
the trickle charging mode (fifth stage).
10-4