In this paper, a battery-powered Internet of Things assisting Cognitive Radio (CR-IoT) network is considered. In CR-IoT network, a set of IoT End Nodes (ENs) are assumed to cooperatively sense the channel. Each EN performs a Spectrum Sensing (SS) and reports its decision to a Fusion Center in order to reach the decision on the PU status. Such monitoring of PU comes at the cost of additional energy resources consumed by the EN to perform SS and reporting, and raises the need to set a suitable protocol to manage the data exchange. The extra operations may exhaust the energy of the EN battery, especially when Low Power Wide Area Networks (LPWAN) technology is used. In this paper, an Eligibility Score-based (ESco) Strategy is defined to reflect the eligibility of an EN to make a reliable SS taking into consideration its battery level. Our strategy is adapted to LoRaWAN Class-B protocol in order to handle real world scenarios. Necessary modifications are introduced to the existing protocol protocol in order to support the synchronization between the ENs and the Application Server, (which the SS need is identified), and the on-demand nature of the SS requests. To evaluate our strategy, LoRa sensors' parameters are considered in our simulations. The numerical results highlight the efficiency of the proposed strategy by showing the extension of the ENs' lifetime compared to classical strategies.