Lex Man, "short battery life" most likely not related to a broken power button but most likely related to water damage. You do want to start with a new battery. Also, make sure that you clean the phone completely if you have any inclination on keeping it for a while. If you do not clean it properly it will continue to corrode until it is damaged beyond any reasonable repair. I'd suggest that you clean it using [guide|5825|this guide]. It was written for an iPhone but all the points are pertinent to your phone as well. After that, replace the battery.
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Lex Man, "short battery life" most likely not related to a broken power button but most likely related to water damage. You do want to start with a new battery. Also, make sure that you clean the phone completely if you have any inclination on keeping it for a while. If you do not clean it properly it will continue to corrode until it is damaged beyond any reasonable repair. I'd suggest that you clean it using [guide|5825|this guide]. It was written for an iPhone but all the points are pertinent to your phone as well. Use [https://www.ifixit.com/Device/Sony_Xperia_Z2|these guides] to work on your phone. After that, replace the battery.
Lex Man, "short battery life" most likely not related to a broken power button but most likely related to water damage. You do want to start with a new battery. Also, make sure that you clean the phone completely if you have any inclination on keeping it for a while. If you do not clean it properly it will continue to corrode until it is damaged beyond any reasonable repair. I'd suggest that you clean it using [guide|5825|this guide]. It was written for an iPhone but all the points are pertinent to your phone as well. After that, replace the battery.