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KraftPowercon Sweden AB, Hjalmar Petris väg 49, S-352 46 Växjö, Sweden, Tel: +46 470-705200, Fax: +46 470-705201,
www.kraftpowercon.com
Umid (%) = 100 x (number of cells from negative up to the measurement point) / (total
number of cells)
Example:
A 110 V battery consisting of nine 12 V battery blocks (6 cells per block). The closest
midpoint will then be the positive terminal on block no 4 or 5, calculated from the negative.
We choose to measure the midpoint in the positive terminal at block no 4. We then have 4
blocks x 6 cells/block = 24 cells, from negative up to the measurement point. The total
number of cells is 9 blocks x 6 cells/block = 54 cells. The formula above gives 100 x 24 / 54
= 44.44 %.
Now set the estimated percentage as the midpoint's actual position.
5.13.4
Parameters for measuring battery temperature
For measurement of the battery's ambient temperature,
an external temperature sensor must be installed, see
section
6.4.3.4. Without sensors, the two alarms “High
temperature, battery” and “Low temperature, battery”
will lose their function. Additionally you lose the option
of using the temperature controlled float charging
voltage.
Start by specifying whether the sensor is connected or not.
For temperature control of the float charging voltage, you need to specify a number of parameters.
These specify two different slopes to the control curve and the limits for the permitted control
range. The data for these parameters is based on information from the battery manufacturer.
In
Figure 1: Temperature curve
the
battery manufacturer's charge curve is
shown with a dashed line. This curve is
approximated to two straight lines with
individual slopes (the thick line).
Furthermore, an upper and lower limit is
specified for temperature control, Ut
min
and Ut
max
. Do as follows to determine the
slope of the two lines:
1.
Take the battery manufacturer's
recommended charge curve.
2.
Draw using a rule a straight line from
the 20° point in each direction
following the curve as closely as possible.
3.
Determine the two points on the drawn lines that correspond to the lowest and highest
temperature possible, T1 and T2. Read from the voltage axis the voltages that correspond to
the line you have drawn. This gives U1 and U2.
4.
Calculate the slopes dU1 and dU2 as follows:
dU1 = number of battery cells x (U1 - Ut
20°
) / (20° - T1)
dU2 = number of battery cells x (Ut
20°
- U2) / (T2 - 20°)
where the voltages U1, U2 and Ut
20°
are expressed in mV/cell.
As an example of typical values, the slopes are specified for a few standard types of battery. The
example uses a 110 V battery with a total of 54 cells.
NOTE: The battery manufacturer's specifications may have changed. These numbers should
therefore only be considered as examples.
1. Tudor, type OPzV: dU1/cell = 4.00 mV/°C
=>
dU1 = 4.00 x 54 = 216 mV
===././BATTERYTEMP.==
Installed: Yes
dU1: 216mV/°C
dU2: 180mV/°C
Out-min: 97.20V
Out-max: 127.90V
________________________________
Select Return
Is
temperature sensor
installed?
Yes
No
________________________________
Ready
T1
20°C
T2
U1
Ut
max
Ut
20°
Ut
min
U2
V
°C
Figure 1: Temperature curve
