In addition to the familiar functions, the Smart Charge system also performs the following functions:
The battery charging current is optimized through continuous calculation of the battery temperature and monitoring of the alternator output voltage.
The alternator load is signaled to the PCM (powertrain control module) in order to provide it with an early indication when an electric component is to be switched on or off, thereby also providing information about imminent changes to the amount of torque demanded by the alternator. By evaluating this information the PCM is capable of increasing the stability of the engine under idling.
The two remaining functions of the Smart Charge system are controlled by the GEM.
Electrical consumers are switched off when the battery voltage is low if the GEM determines (as a result of the message received from the PCM on the CAN bus via the instrument cluster) that the battery voltage has dropped below the threshold value.
When the threshold for low battery voltage is reached the GEM switches off the following consumers in this order at intervals of 5 seconds:
If the battery voltage increases back above the lower threshold then all of the consumers which were previously switched off are reactivated by the GEM.
Once the electric consumers have been reactivated their status is "switched off", i.e. the consumers are switched off and await an input signal provided from the relevant switch via the GEM; this means that the driver needs to switch these components back on again.
Electrical consumers are switched on when the battery voltage is excessively high if the GEM determines that the battery voltage has increased above the threshold for overvoltage and the charging system warning indicator has come on.
When the threshold is reached the GEM switches on the following consumers in this order at intervals of 5 seconds:
When these components are deactivated again their status is "switched off". This means that the consumers are waiting for an input signal provided from the relevant switch via the GEM.