Abstract: The electrical resistance aging properties of a coating intended for use on a base material in a primary alkaline cell battery are be tested by manufacturing at least one test device, measuring a first and a second electrical resistance across two distinct circuits in the device, and calculating the effective electrical resistance at the interface between a cathode mix and a coated surface of the base material as the difference between the two electrical resistances. By storing the test device at temperatures above ambient, the aging properties of the coated surface resistance are estimated by repeating the electrical resistance measurements at predetermined time intervals at ambient temperature.