bq20z80-V101
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SLUS625D–SEPTEMBER 2004–REVISED OCTOBER 2005
Voltage( ) (0x09)
This read-word function returns an unsigned integer value of the sum of the individual cell voltage measurements
in mV with a range of 0 to 20000 mV.
Current( ) (0x0a)
This read-word function returns a signed integer value of the measured current being supplied (or accepted) by
the battery in mA, with a range of –32,768 to 32,767. A positive value indicates charge current and negative
indicates discharge.
NOTE:
SBS.Current( ) is the average of four internal current measurements over a
one-second period.
AverageCurrent( ) (0x0b)
This read-word function returns a signed integer value that approximates a one-minute rolling average of the
current being supplied (or accepted) through the battery terminals in mA, with a range of -32,768 to 32,767.
SBS.AverageCurrent( ) is calculated by a rolling IIR filtered average of SBS.Current( ) data with a period of
14.5s. During the time after a reset and before 14.5s has elapsed the reported SBS.AverageCurrent( ) =
SBS.Current( ).
MaxError( ) (0x0c)
This read-word function returns an unsigned integer value of the expected margin of error, in %, in the
state-of-charge calculation with a range of 1 to 100%.
SBS.MaxError( ) is set to 100% on a full reset, and is updated by the following mechanism.
On QMAX and Ra table update, the SBS.MaxError( ) is set to 1%.
On QMAX update, the SBS.MaxError( ) is set to 3%
On Ra table update, the SBS.MaxError( ) is set to 5%
SBS.MaxError( ) is incremented 0.05% for every increment of SBS.CylceCount( ) after the last QMAX update
RelativeStateOfCharge( ) (0x0d)
This read-word function returns an unsigned integer value of the predicted remaining battery capacity expressed
as a percentage of SBS.FullChargeCapacity( ), in %, with a range of 0 to 100%.
AbsoluteStateOfCharge( )(0x0e)
This read-word function returns an unsigned integer value of the predicted remaining battery capacity expressed
as a percentage of SBS.DesignCapacity( ), in %, with a range of 0 to 100% with any fractions of % rounded up. If
SBS.BatteryMode( ) [CAPACITY_MODE] is set, then the predicted remaining capacity is a percentage of
SBS.RemainingCapacity( ) / SBS.Design Energy( ).
NOTE:
SBS.AbsoluteStateOfCharge( ) can return values > 100%.
RemainingCapacity( ) (0x0f)
This read-word function returns an unsigned integer value, with a range of 0 to 65535, of the predicted charge or
energy remaining in the battery. The SBS.RemainingCapacity( ) value is expressed in either charge (mAh) or
energy (10 mWh), depending on the setting of SBS.BatteryMode( ) [CAPACITY_MODE].
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