Function and structure
Batteries_Rail_Power_Manual_en02.docx
21
Note
If the battery temperature ≥ is 60 °C, the charging process must be interrupted to prevent
damage to the cells. Select a control that does not resume charging until the battery temperature
has dropped to ≤ 55 °C
Note
You can assume that the temperature sensor is defective if the battery charger is measuring
temperatures above +80 °C or below -50 °C. The battery charger will not be able to operate the
battery if the temperature sensor is not in the correct range.
In this case, set the battery charger so that the charging voltage is limited to 2.21 V/cell (float
charge at 30 °C).
The battery charger should generate a SERVICE message and the defective temperature sensor
should be replaced within a few days.
5.4.3.2.
Two stage, temperature compensated charging (IU0U-charging)
A two-stage charge (constant current / constant voltage) is recommended for rail.power
batteries. In addition, a temperature-compensated charging characteristic is required in
order to avoid excessive currents at high ambient temperatures and to fully charge the
batteries at low temperatures. Based on the charging parameters at design temperature, the
charging voltage is increased or decreased depending on the measured battery
temperature.
The following figure shows the charging voltage per cell depending on the battery
temperature monitored by the charger. It shows the temperature compensated charge with
- 4 mV/°C per cell based on 20 °C for rail.power batteries related to a two-stage constant
voltage charge with current limitation.
1 = Float charge
2 = Boost charge
Charg
ing
V
o
lta
ge
[
V
]
Electrolyte Temperature [°C]
