Temperature-Dependent Battery Charge

Temperature-Dependent Battery Charge

The optimum charge voltage is set by the power module according to the battery temperature.

The power module monitors the voltage at the battery and specifies the charge voltage for the alternator via the engine electronics (DME or DDE).

Due to the load-dependent voltage drop on the supply line between the alternator and the battery, the values for
- TARGET alternator voltage
- and SPECIFIED alternator voltage can differ.







Maximum values of the battery voltage depending on the battery temperature:
16 V at -17 degrees C
13.5 V at 40 degrees C

The voltage range can be limited to the following values by coding:
Maximum value 15.5 V
Minimum value 14.0 V

If the measurement of the battery temperature is outside the tolerance
- due to defective temperature sensor
- or due to breaks in wiring the voltage at the battery is adjusted to a fixed value of 14.3 V.

Notes for Service department

Operational test of charge control
Cool down the temperature sensor with cooling spray and at the same time observe the voltage. The cooling of the temperature sensor must lead to a rise in voltage.

The rise in voltage takes place slowly in 0.1 V steps every 5 seconds.