Click on Freeze List to disable and re-enable auto-
scrolling. The On Top check box causes the datalog win-
dow to remain on top of other windows; when un-
checked, other windows may cover up the datalog
window. You may minimize the datalog window at any
time without disrupting the datalogging process.
The Datalog Settings on the menu bar provides for set-
ting the time interval between each point datalogged.
This pull-down menu provides options with a minimum
of five-second intervals. Another option allows stopping
the datalog when the EV2903 detects that the batteries
are idle.
The datalog is saved as a text (.txt) file. If you desire a
plot, we suggest importing into a program such as Micro-
soft Excel.
TM
Standard Operation and Helpful
Hints
Learning the Battery Capacity
Upon initialization of the program and/or inserting a dif-
ferent or new set of batteries, preferably start out by
charging the batteries to “Full.”
Then, discharge the
batteries until “Empty.” Doing this will allow the
EV2903 to “learn” the capacity during the first discharge
cycle.
Batteries
For optimal battery performance, replace batteries as a
complete set. The EV2903 charges the battery stack in
series and not each cell individually. Charging termina-
tion takes place when any cell is fully charged.
Dis-
charging terminates when any cell reaches EDV. Please
refer to the bq2903 data sheet.
Battery Stack Voltage (EDV)
When the bq2903 senses EDV, it disconnects the battery
stack from the load. At this time, the bq2014 Gas Gauge
cannot sense the battery stack voltage, sensing only 0
volts. The battery stack voltage will decrease quickly
due to the averaging routine internal to the bq2014.
When the EV2903 detects EDV, it will display “N/A” as
the Battery Stack Voltage.
Calibrating Battery Stack Voltage
The Battery Stack Voltage display should be within
±
90mV of the true battery stack voltage. For better ac-
curacy, use the Calibration button.
Measure directly
across the battery stack and input this value in the Cali-
bration window. Select Done.
For three- and four-cell calibration, measure directly
across the “+” terminal of battery 1 to the “-” terminal of
battery 3.
Message Status Bar
The lower right-hand corner of the EV2903 screen will
display helpful messages throughout the operation of
the EV2903 program. This message bar will indicate
the number of complete charge and discharge cycles.
Utilities Menu
Use this menu to calibrate the battery stack voltage and
to set the number of data points which the EV2903 uses
to average the current. Benchmarq suggests using 60
data points, which will smooth out graphs showing the
current.
Also in the Utilities menu are options for the Register
window and Flag window. Use these windows to moni-
tor the status of the bq2014. Please refer to the bq2014
data sheet for information concerning these registers
and flags.
5
EV2903
