Just a solution because i dont like much the new phones and i own a nexus 5 try using battery guru it extends battery life much.If you are desperate for an upgrade and concerned about battery life go for the moto x play it offers a feeling to the vanilla android also
What I am using is honor ,which belongs to Huawei . It has a good battery ,when it is only 10% of the electricity,I still use it to listen to music for 1 hour and left 8% of the electricity.