The battery drain after updating to Android 12 on your Pixel 5 is a pretty common issue. Sometimes the system is still indexing and optimizing apps in the background right after an update, which can cause higher battery use for a day or two. If the problem persists beyond that, try checking for apps that might not be fully compatible with Android 12 yet and consider doing a cache partition wipe from recovery mode—it can clear out old data that might be causing inefficiencies. Also, ensure your location and background activity permissions are set sensibly, as some apps might be running excessive background processes after the update.

@Aman Mehta The build number you mentioned, SP1A.210812.015, actually corresponds to Android 12’s initial release for Pixel devices, so it’s unlikely the update itself is the direct cause of sudden battery drain. More often, battery issues post-update come from apps not being fully optimized for the new OS version or background processes resetting. It might help to check battery usage stats to see if any app is unexpectedly consuming power and consider a cache partition wipe or a factory reset if nothing else works.