Kindles will go to sleep after 10 minutes of inactivity. There isn't an adjustable timer.
If you've downloaded a lot of books, you can expect a temporary increase in power usage while the device indexes the books. If it doesn't level off in a day or two, try rebooting: Make sure the Kindle is charged, unplug it, press and hold the power button in for a full 30 seconds (time it, and ignore prompts), then release and leave it alone for a few minutes while it restarts.
it should be around 21 hours if you're talking about a Paperwhite. The 10th Gen Kindle says this in the Product Details:
A single charge lasts up to four (4) weeks, based on a half hour of reading per day with wireless off and the light setting at 13. Battery life will vary based on light settings, wireless usage. Audible audiobook streaming over Bluetooth will reduce battery life.
and that's around 14 hours. Also, if it's brand new and you've downloaded a bunch of books, those books all need to be indexed and that will eat up any battery charge very quickly. It's usually a good idea to put it on a charger anytime you're not using it during the first few days
ETA: Other things also affect battery usage: reading speed (more page turns = more battery use), frequency of using the definition or instant translation functions, looking at footnotes, page refresh set to every page or every 6 pages ( take less) as well as books stuck indexing
Making assumptions about how a thing works is counter productive.
Amazon does have a 30 day return window so you can vent your outrage on them that way, perhaps driving them out of business to your endless glee. Buy the device that does the thing you want done and life is a lot smoother and you won't have to get angry at people or things that are not responsible for the problem.
You could, you know, try *suggesting* this as a worthy feature to Amazon.
NOTE: I do NOT speak for or represent Amazon in any fashion. This is a customer to customer forum.
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