Battery Charging; Battery Safety; Battery Capacity - Sony Ericsson CMD-Z7 Service Manual

2.5 Battery Charging

There is no charging circuitry in the battery pack. The CMD-Z7 has complete charger function internally.
The telephone can be charged only with the battery connected the phone. This situation can be sub-divided into
two situations: the phone is on or off. It can be charged with the AC Adapter, Travel Charger or Cigar Lighter
Charger.
The battery symbol is used to indicate the charging, and to indicate when the battery is fully charged. This is done
using the following sequence of icons:
The uncharged segments of the battery are moving in a right to left manner until the charging stops. The
sequences for each charging level is repeated until the battery is charged to that level.
When the charging sequence is finished the flashing of the battery level sign stops.
The phone shows the full-battery icon.
Note: When the battery pack is completely discharged, it can take some time until the battery icon appears when
charging

2.6 Battery Safety

The battery pack contains a single Li-polymer cell, a safety circuitry and, in addition, a microprocessor unit which
manages RTC information by reading out the binary counter value in the microprocessor. The charging circuitry
and the safety circuitry together guarantee a double fail-safe battery pack. This means that each component can
be either short or open and still all the safety requirements will not be violated.
The safety concept protects against:
Over voltage: The charging is stopped when Battery Voltage (Vbat) reaches 4.27V- 4.3V. The charging resumes
when Vbat falls below (4.045V - 4.145V).
Under voltage: When the cell voltage drops below 2.242V – 2.358V the cell is disconnected for discharging.
Charging is still possible.
Current fuse: Finally, if all protection functions are out of order due to abnormal condition, the current fuse protects
the device from explosion and fire with melting. The fuse melts 10A during 1 second.

2.7 Battery Capacity

QN-Z7BPS 680mAh; Lithium Polymer Technology
The phone can be charged even during making phone calls.
However, the shortest charging time will be reached when the phone is switched off.
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