It happened to me too and I'm so fed up that I'm here to share my woes with all of you!
My battery level has also completely disintegrated since this update. I've gone through every setting on my phone and turned off lots of features as well as updating all my apps in hopes that it would help, but nothing has.
Previous to update 17 I had excellent battery life; I'm using a 2nd Gen SE - it is an older model but the phone itself was nearly new. Now since the update I'm suddenly being told that my battery needs replaced.
No suggestions by Apple or experts has changed a thing and it's such a widespread issue that it makes me suspect that it's a flaw built into the update, perhaps intentionally.
Supposedly after any update there are background actions occurring that can affect battery life for awhile, but after a month nothing has gotten better.
Then of course they released 17.1.2, which only addressed some security issues, and next month another big update will be released, so who is to say how long we'll have to wait after it to see if it helps?
I really hope that they finally do something to fix this battery drain, but I'm not holding my breath.
Apple has a history of destroying battery life on purpose in an attempt to force users to upgrade, they've even been sued for it by entire countries and found to be liable.
But apparently that hasn't stopped them from continuing to engage in bad business practices, because here we are.
They think it'll make people rush out to purchase new devices, but all it really results in is a lack of trust from their customers.
After this poor experience I don't think I'll buy another iPhone because there's no guarantee that they won't purposely make my device obsolete or refuse to fix update issues like this in a reasonable amount of time.
There is no excuse for one of the largest tech companies on the planet to not do everything in their power to correct an issue that they created as soon as possible, so the only conclusion that I can come to is that they wanted this to happen.
