Accelerated-life testing and thermal effects in valve-regulated lead-acid batteries

Elevated-temperature data and test methods are presented for Gates products commonly used in telecommunications applications. Failure modes are enumerated and life projections based on these tests are presented and evaluated; where possible, comparisons are made with actual product field failure results and it is found that substantial discrepancies exist. Temperature factors in both laboratory testing and field conditions are discussed and simulations of temperature effects in above-ground cabinets show that life projections based on average daily temperatures may be overly optimistic. It is shown that temperature and cell chemistry can have a dramatic impact on product life at elevated temperatures. Accelerated-life tests at 60-80°C show that Gates products will meet or exceed that published float life of 8-12 years at 23°C. Thermal effects in telecommunication applications are such that the interior of the battery will always be hotter than the surrounding environment by some factor, the latter having a profound impact upon battery life