[knc1]

Screen at 28% ?
Let me guess, that model has an IPS screen.
Pretty, but at a price in power usage.

Turn the screen off and use a Kindle as a remote screen.

Does your traffic congestion application mark those congestion spots that where caused by people who where looking at their cell phone screen rather than where they where going for you?

Avoid becoming one of the congestion spots yourself, turn the screen off.

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Yes, any sort of 'stream' handling means the cpu / electronics never has time to power-down, even on their own time scale of doing things people can't notice.

Record your music (or whatever) onto the phone, play recorded music rather than streamed.

Power your 'phone from the vehicle - I.E: Use a 'car charger' for it.

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Having decreasing storage capacity over the age of the battery, usually noticed as shorter times between re-charges, is a fact of life with the battery design.

Sometimes made even worse by the usage patterns of the user.
As the battery ages, it is even more important not to let it "deep discharge" -
Keep in mind the Capone quote:
"Vote Charge early, vote charge often."