Capacity of the battery is usually specified in Ampere-Hour. So far, while designing a routing protocol people are considering that if C is the capacity of the battery and the current drawn out of it is at rate R then total time to evacuate is T=C/R. On contrary, the batteries show Rate Capacity Effect. That is, Capacity of a battery decreases with increase in discharge current. Thus lifetime of the battery also decreases significantly with increase in discharge current. Researcher have been minimizing this effect using proper pulse shape and traffic shaping, all at physical layer of communication protocol. Our present work deals with these limitations of realistic battery model at network layer in routing protocols itself. We are presenting here two types of power aware algorithms to overcome this issue. In our algorithm Rate Capacity Effect, Minimum Drain Rate and Minimum Transmission Power Constraints are exploited altogether as a metric to design a routing protocol, which minimizes Rate Capacity effect and ultimately gives improved lifetime of the sensor network. This is to be noted that this improvement in lifetime of the battery used in sensor nodes is in addition to the improvement done at physical layer by other researchers.