If you have HomePods and worse-than-expected battery life on iPhone, try turning off Settings > General > AirPlay > “Transfer to HomePod.” It’s expensive in power as it’s constantly ranging.

In the screenshot, I turned off the setting during the middle charge. First time I have seen flat battery drain in months.

A battery usage graph showing usage at a very negative slope from 100% to 25% followed by a recharge and a less negative slope followed by a near zero slope for a duration. Less usage over time.

Another unexpected drain: the Finder device setting “Show this iPhone when on Wi-Fi” causes a large amount of energy usage by lockdownd, via saagar.

Discovered this using his excellent sysdiagnose energy log viewer.

Graph of energy usage, with a selected region showing battery usage going down quickly.List of energy usage by process by percentt