USE AND FUNCTION OF THE BATTERY SENSOR
ENERGY MANAGEMENT
The electronic battery sensor is an important part of the vehicle energy management. The sensor informs the car of the exact battery status, measures the temperature and controls the charging voltage and charging current accordingly.
The massively increased on-board currents in current vehicle models and in particular the micro-hybrid start-stop applications and recovery of braking energy place new demands on car batteries. Increasingly, kinetic energy is also converted into electrical energy during coasting (= free rolling of the car) and this charges the battery.
Use and function of the sensor
Energy management continuously records parameters such as voltage, current and temperature via a battery sensor. These measured values are used to calculate important parameters such as state of charge (SOC), state of function - starting ability (SOF) and overall condition - age of battery (SOH State Of Health) and a variety of other values.
The data are sent to the vehicle computer. The driver then decides on the energy balance in the vehicle and, if necessary, restricts the use of comfort consumers such as heated seats or air conditioning, switches off the start-stop function and signals this to the driver on the display with the corresponding information. If the alternator then recharges sufficiently, the control unit automatically reactivates all consumers and functions.
Customer benefits in brief:
The ultimate goal is to ensure that the engine is started at all times and, in doing so, avoid vehicle failure. The sensor also supports intelligent alternator control, which reduces CO2 emissions, saves fuel and protects the environment. If the battery no longer provides the desired performance, the system records a „defective battery“ and thanks to this early warning system, a plannable battery exchange is feasible.
Industry-specific abbreviations quickly explained:
BEM - Battery Energy Management =
BMS - Battery Management System =
EEM - Electrical Energy Management =
EMS - Energy Management System.
EBS - Electronic Battery Sensor =
IBS - Intelligent Battery Sensor.
SAM - Signal Acquisition and Assessment Module (control unit).
For many more abbreviations, see: Battery ABC.
What to look out for when charging!
Connect the red clamp to the positive terminal and the black clamp to earth*
- In modern vehicles, this is particularly relevant due to the battery sensor, as otherwise the sensor cannot detect the charging current correctly and may generate an error message. Once again: The charging current must pass through the sensor, otherwise the control unit will not know that the battery has been charged and will report "Restart not possible" in the worst-case scenario.
- *This recommendation was also made in the past, because of the sparking when contacting the negative terminal. (Ground = bare metal point away from the battery).
- All of this information must also be taken into account for the jump start!
The battery sensor is an indication of a vehicle with start-stop function and battery energy management (BEM). Never install a conventional starter battery in a vehicle with start-stop technology that is equipped with an AGM or EFB battery as standard.
Not even if the automatic start-stop system is switched off temporarily or permanently, because the cyclical load caused by additional electrical or electronic consumers is enormous and leads to the battery failure of a conventional starter battery within a few months! Continuous operation in a partially discharged state (SOC State Of Charge at approx. 70%) alone is a guarantee for the premature failure of a conventional battery.
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