Lead Batteries for Dash-Cam Applications: Experiences and Lab Test Development

Abstract

In modern road vehicles, one of the major energy consuming devices is the dash-cam, which is becoming more popular in many markets for several reasons. This dash-cam device is also operated during vehicle stand-still, therefore the energy demand usually is covered by the car's lead starter battery. In this paper, the influence of dash-cams on vehicle electrical systems in two different vehicles was investigated on the road and on the roller dynamometer. In both vehicles, similar strategies for battery operation and SoC maintenance were observed, but significant differences were found in Start/Stop characteristics and low-temperature operation. Vehicle A allowed for a higher DoD range during discharge, while vehicle B allowed for Start/Stop operation also at lower temperature conditions. In particular, the Start-Stop system was investigated in terms of average SoC, but also missed engine stop opportunities and premature engine restart events. Based on this knowledge, battery laboratory tests were developed that represent the operating mode of a vehicle with an activated dash-cam under controlled conditions. One test was an accelerated life test that was focused on the maximum charge throughput of the test batteries, and another test was focused on the reaction mechanism, which was found to be sulfation. These tests were validated with lead batteries of different technologies: AGM batteries (absorbent glass mat) turned out to be superior over flooded batteries in this vehicle application.