What is the battery temperature sensor? What are the symptoms of a battery temperature sensor malfunction? What is the optimal operating temperature for the battery ?….?
What is a Battery Temperature Sensor?
Modern vehicles have many sensors. Some sensors serve a more important purpose than others but the main purpose of all sensors, regardless of their size or purpose, is to gather data and then transmit it to an on-board computer. One of these sensors is the battery temperature sensor. This sensor can also be called a battery monitoring sensor, smart battery sensor (IBS), or electronic battery sensor [EBS].
The battery temperature sensor is usually a thermistor. It is usually composed of two wires on the negative end of the battery terminal. It determines the ambient temperature and measures the resistance to the battery. The resistance will change with temperature.
These data are then sent to the PCM (on-board computer). The PCM monitors the temperature, voltage, and state of charge of the battery. These inputs are used by the PCM to fine-tune charging system voltage and idle speed, and other parameters that will improve fuel efficiency and prolong battery life.
The battery temperature changes the ideal charging voltage. The battery temperature sensor gives the information needed to adjust the charge voltage continuously based on actual battery temperature. Temperature compensation ensures that the voltage of the battery is sufficient to compensate for temperature fluctuations during operation.
While the primary purpose of the battery temperature sensor, is to provide voltage necessary for battery longevity, it also performs other important tasks. The battery temperature sensor sends a signal back to the PCM when it is cold to disable functions like heated seats, navigation and air conditioning. A warning message will be displayed on the instrument panel in this situation. The PCM will charge your battery using the alternator. Once the battery is fully charged, all accessories will become available to you again.
In vehicles with Start Stop, the function of the battery sensors is especially important. The battery management software must check that the battery has enough charge to start the vehicle. The Start-Stop function will be disabled if the battery charge drops below 50%. These vehicles usually have a higher charging system current. On some vehicles, the Start-Stop may not function if the sensor or battery is removed. The PCM will then learn the battery parameters.
The battery temperature sensor allows for the control of the alternator much more efficiently. This reduces the engine’s load, which in turn saves fuel and reduces emissions.
Like all sensors, the temperature sensor’s battery wears down and gets damaged over time. The most common reason the sensor fails is corrosion, dirt, or battery acid. The battery sensor can be damaged during maintenance and removal. The fault can sometimes be resolved by disengaging the battery and cleaning both the connector and the sensor. In other cases, the component will need to be replaced.
These fault codes are related to the temperature sensor battery:
- – P0514 Temperature Sensor Circuit Range/Performance
- – P0515 Temperature Sensor Circuit Malfunction
- – P0516 Low Temperature Sensor Circuit for Battery Temperature Sensor
- High Temperature Sensor Circuit for P0517 Battery Temperature Sensor
What is the ideal operating temperature for a battery?
The battery can be described as a storage device for energy. It contains chemicals. The current results from the reactions between those chemicals. The temperature affects the rate at which the chemical reaction takes place. The increased rate of chemical reactions can increase battery performance to a certain extent. Temperatures above 40°C can cause permanent damage to the chemical (electrolytes), which may result in battery life being reduced and shorter charge cycles. Thermal runaway is the most serious.
The chemical reactions of the batteries slow down at low temperatures. The internal resistance of a battery increases while its ability to generate high current drops. On cold days, a car’s battery won’t produce enough current to turn the engine on. The electrolytes in the battery can freeze at extremely low temperatures and cause the battery to fail.
The charging voltage must always be controlled accurately to ensure safe and efficient charging. Temperature is a factor in the optimal charging voltage. The battery temperature sensor ensures that the proper charging voltage is delivered to the device at the right times.
Low charging voltage when the battery is cold will cause it to become undercharged. Lead-acid battery damage is caused by insufficient charging. The battery’s positive plate will deteriorate if it is heated. These conditions can lead to a shorter battery life and lower performance.
What are the Signs of Battery Temperature Sensor Problem?
Although the battery temperature sensor is intended to last for the lifetime of the vehicle, debris and contamination can cause it to fail or prematurely wear down. A malfunctioning or damaged battery temperature sensor will cause the vehicle to display common warning signs and symptoms that warn the driver. The following are some common signs and symptoms that indicate a damaged sensor.
Fluctuations of Engine Speed (RPM).
Most often, the battery does not have any effect on the engine once the vehicle has started. The voltage regulator or alternator supplies power to other components. If the battery temperature sensor is damaged, it can interrupt the electrical flow to your ignition system. This could cause engine idle fluctuations.
Low Battery Voltage
A bad battery sensor can’t accurately measure the temperature of the battery and could send inaccurate information to the computer. This may lead to insufficient battery charge. If the battery isn’t charged properly, it can slowly discharge. This is a sign that the battery does not have enough power to turn the engine on and prevents you from using electrical accessories.
Engine Malfunction Lamp
The engine fault lights will be lit if the computer on board sets the fault codes. Sometimes the instrument cluster’s battery warning light will also go on in some cases. The indicator light is usually a sign of a problem in the charging system.
Locate the Battery Temperature Sensor
The battery temperature sensor is normally mounted on the positive terminal of the battery. This clamp connects to the vehicle body for grounding. Depending on the vehicle model, the location of this sensor might vary. A battery sensor may be located on one terminal, while others are on both. Some vehicle models have it located directly beneath the battery. It is because heat is warmer towards the bottom and center of the battery. This means that it is easy to find as it will always remain in the same place around the battery.
The battery temperature sensor plays an important role in modern vehicles’ charging systems. It is therefore impossible to remove or cancel the sensor.
You will need to remove the two terminals from the battery in order to replace the sensor. You can then unplug the sensor, and install your new sensor by unscrewing it.
