In this paper we present a method for experimental lifetime measurements of sensor networks. Despite the importance of experimental validation, none of the lifetime models proposed so far has been validated experimentally. One of the reasons for the absence of practical validations might be the long lifetime of batteries which make the validation of the proposed models non-trivial and time consuming. Our solution enables validation of lifetime models within a reasonable amount of time. We also use our method to validate a simple mathematical model that provides bounds on the lifetime of sensor networks.