AI-based battery health monitoring
How is battery health monitored? What is a battery monitoring systems?
A battery health monitoring system (BHMS) usually consists of a microcontroller rack and a software user interface. It is designed for 24×7 continuous monitoring of all batteries of a battery bank in order to identify weak batteries before they fail, and to improve the overall system performance. Such battery health monitoring systems are commonly used in stationary applications like data centers.
In vehicles, reliable and precise information about battery state of charge (SOC) and state of health (SOH) still remains a concern, both for users and for the industry. Even conventional busses and trucks with diesel engines frequently fail in autumn and winter, as temperatures drop and battery health decreases. Few vehicle fleets are equipped with solutions to monitor battery health in a centralized manner by the fleet manager
How are battery health stats monitored with our AI-based solution?
COMPREDICT has developed a virtual sensor that can detect the battery condition status using machine learning algorithms. It can be retrofitted to any vehicle with a telematics system on board: conventional light vehicles, trucks and busses as well as hybrid.
What we do is that we measure the voltage during a short period while the engine is being started: approximately 10 seconds. The AI-based virtual sensor analyzes the voltage curve over time and detects the battery health status automatically.
No manual parameterization is required to tell the algorithms, whether the vehicle is a passenger car or a truck or a bus. As soon as a vehicle is connected for the first time, the software runs an automatic self-parameterization, the same way like it’s done in the use case for vehicle overload detection.
The driver just needs to make sure that the battery is in good condition when the vehicle is connected for the first time. Either a new battery is mounted, or a manual batter check done prior to connection. After this initial drive, the battery is monitored automatically by the software. During daily operation, real-time information about the current health status of each vehicle’s battery is either sent to the telematics provider or displayed on AI-View, our own data visualization platform.
Devices & input values for battery condition monitoring
As input for our algorithms we need a voltage signal with a frequency of, ideally, 30 Hz. If the frequency is smaller, only a part of the engine starts will generate usable data for monitoring. The voltage can be measured directly by the vehicles themselves or by simple devices commercially available on the market, like dongles, and connected to the telematics system. Because of the short period of time we analyze, the data volume is very small.
We are currently deploying at scale our virtual sensor into commercial telematics solutions in order to make it available for end-users and fleet managers.
Give us a sign to integrate it into your favorite telematics solution!
Battery types for cars, trucks and busses
Lead-acid-batteries are a cost-efficient solution as starter batteries for conventional vehicles with diesel or gasoline engines, without start-stop function. They support only a limited number of power-consuming on-board accessories (autoradio, air conditioning, USB devices …) and their typical lifespan is around 4 years.
An EFB battery (“Enhanced Flooded Battery”) is an improved version of the standard Lead-acid-battery, with an additional polyester scrim (sort of fabric) to stabilize the plates. They have an increased lifetime and a better discharge performance, which makes them suitable for vehicles with a simple start-stop function.
AGM batteries (“Absorbent Glass Mat”) also have a cell chemistry based on Lead and Lead-oxide but the liquid electrolyte is absorbed in a fleece separator made of glass fibers. Key advantages are that they can cope with higher power demand, an even longer lifetime and that they are leak-proof. They are used in vehicles with automatic start-stop systems with brake energy recuperation, or with power-consuming on-board accessories.
Busses and trucks can use any of these battery types depending on motorization. As they work with 24 Volt, they have two 12-Volt batteries in series.
Mild hybrid vehicles operate at a voltage of 48V. The most dominant solution for this application are Li-ion batteries. Sometimes four 12-Volt ABM-batteries are mounted in series. Among other alternative solutions, Sodium-ion batteries can also be used. These work without Lithium or Cobalt, and have a much lower risk of thermal runaway than Li-ion batteries.
Hybrid electric / plug-in hybrid electric and full electric vehicles require higher voltage, in the range of 400 – 800 Volt. For these high-voltage applications, Lithium-ion batteries are currently state-of-the art. A variety of other battery types are under development, like hybrids between supercapacitors and batteries, or Sodium-ion cells. In all of these electrified vehicles, a battery management system (BMS) controls complex charge/discharge strategies in order to preserve battery health in various environmental conditions and usage profiles.
How to check the voltage of car batteries manually?
The nominal (normal) voltage of Lead-acid, EFB and AGM batteries is 12 Volt. When fully charged and at rest (vehicle parked), as a rule of thumb, the voltage should be between 12 and 13 Volt. This depends on outside temperature and battery health status. It decreases with battery age or when the car is parked for a long time. When the voltage of a 12-Volt battery drops below 10V at rest, then it generally needs to be changed.
A wide range of battery testers are commercially available for personal or professional use, for 12 Volt or higher range. Such a manual check of the battery always takes time, first to take the tester to the vehicle, then to access the battery and to test the battery with engine off and on or through any other procedures. Most of us do not do a regular check, even professional drivers of light duty vehicles, of trucks or busses. Imagine a fleet: checking each vehicle by hand and taking manual notes of battery status is time consuming and error prone.
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