5
1.3.3 Specific Gravity and Temperature
Specific gravity (SG) and temperature readings can be entered manually or
automatically from a compatible data storing hydrometer. In automatic mode,
the user connects the hydrometer to the Cellcorder via an RS-232 cable and
transfers the readings by pressing the appropriate function key.
In manual mode, the display prompts for the readings for each cell. The
Cellcorder automatically inserts the first two numbers of the specific gravity
reading to speed up the entry process. For example, for a reading of 1215, the
display shows SG = 12 _ _ and the user enters the 1 and 5. After specific
gravity is entered, enter the temperature.
1.4 System Features
This section describes the features of the Cellcorder.
1.4.1 Float Voltage Readings
The Cellcorder measures the voltage applied during full float operation. The
voltage range covers all cells or modules up to 16 volts. Reading accuracy is
to four full digits.
1.4.2 Internal Cell Resistance
Internal resistance of a cell can be determined by how that cell responds to a
momentary load. The instantaneous voltage drop and load current applied are
used to calculate the resistance. The Cellcorder algorithms make this
measurement possible on cells that are floating on-line. This method is useful
for determining weak, potentially failing cells when comparing internal cell
resistance of all the like cells in the string. For more information, refer to
Application Note CC-001
.
1.4.3 Intercell
Resistance
The Cellcorder measures and displays the total resistance of the connection
between the terminals of two cells electrically connected to each other. This
measurement includes resistance of the connector and the contact resistance
at the points of connection to the cell terminals.
1.4.4 Auto
Ranging
The Cellcorder automatically selects the correct voltage range and load
resistor for the test being performed.
