Greg Barnett - Vehicle Battery Fires: Why They Happen and How They Happen

The vehicle of today is as much electrical and electronic as it is mechanical. The backyard mechanic has been replaced with highly trained dealership technicians. Engineering demands are in a constant state of change. The wiring harness on the average vehicle has become a large maze of wires routing throughout the vehicle.

The rise in the use of electrical and electronic systems has come with a cost: The simple truth is that electrical fire is the most common type of fire occurring in automobiles. Reporting of fires to the National Highway Traffic and Safety Administration must occur within days of the auto manufacturer learning of the event or the manufacturer will risk incurring fines that can run into the millions of dollars.

The first rule in fire analysis of automobiles and related products is that there are no absolutes . Electrical system failure modes vary widely and depend on many factors. Generally, for an electrical failure to cause a large fire, some type of fuel must be in the immediate vicinity of the failure.

Still, if no fuel is available to help fire propagation, the electrical failure can still be catastrophic. The vehicle may well be destroyed by smoke damage. However, with a nearby source of available fuel, the damage path will be far greater.

Any investigating engineer or technician who has been assigned to troubleshoot the cause and origin of a fire can only respond according to their individual level of training and experience. Troubleshooting is not a skill that can be taught in the classroom. It is a skill honed by many years of hands-on experience.

Care should be exercised so that the investigation does not bend the facts to fit a given fire theory. Rather, the big picture should be examined in context with the evidence discovered.

Because the topic of electrical fire is not a widely taught subject, the purpose of this book is to assist in the analysis with some understanding of the issues faced in electrical system design, battery construction, fault modes, etc. The investigating engineer should apply both deductive and inductive reasoning to the analysis. The scientific method should not be discarded in an attempt to make a pet fire theory work.

However, some fires have consumed the evidence to the point where a determination cannot be made with any degree of certainty. In this instance, evidence will be quite limited. Therefore, the analysis will have its limitations, and this fact should be included in the discussion. In some cases, a cause undetermined report is all that the evidence will support.

The following is a brief history of the battery from the earliest cell discovered in antiquity to the modern lead-acid battery. Many more developments have occurred between inception and use in the modern automobile. Only the more notable developments are covered. A historical timeline is included to credit the inventors and innovators that added to the development of the lead-acid battery. The more modern developments are discussed in later chapters. Greater focus is placed on the lead-acid battery, because this design is the most common in automobiles worldwide.

The descriptions and basics of the battery are covered for readers unfamiliar with this specific technology. Otherwise, you may wish to skip ahead unless you are a fan of history.