Share your experience!
As stated, when the phone reachs low battery (30%), it sounds off loudy.
Anyway to disable it?
Hi @lenz_au, I understand your concern and will make sure to forward your thoughts on this internally as user feedback. As for a workaround, I can only refer to my previous post here. 
Landed here for the same reason, shocked that something as basic as this would get through. Do you guys not test these units before putting them to market. It's so annoying and counter productive, I check my phone every time I get this notification, defeating the purpose of it, wasting more battery.
Many of the changes we do are based on user feedback and we always strive to be on the forefront when it comes to listening to our users and consumers. I understand that some changes such as this one may be a bit more difficult to get used to than other changes, and that some users may prefer how it was before - but rest assured that I will forward this internally on your behalf as user feedback @Lyonsk3.
Z5 is my fourth Xperia smartphone.
First it was annoying blue tint on low light photos that was never fixed.
Now it's annoying battery sound notifications.
If there's no improvement soon I'm moving to different brand.
Kind regards.
For feedback:
it's annoying that the phone beeps at certain battery levels.
I don't want to turn off my phone at night, because people should be able to ring me out of my sleep in important situations.
Battery at 30, 15 or 4 percent is not important, not at all. The battery indicator is permanently displayed for exactly that purpose.
I am all for disabling these warning sounds (or better: allow me to disable/enable it).
I gave away my Z1, because all kinds of notifications permanently interrupted my sleep. Never happened with HTC.
Found myself here for same reason but I don't blame the Z5. My phone only started doing this since most recent android update. Longpress on the low battery notification and disable peeking. This can also be found in notification settings for the app System UI
@cwarky I have not had the chance to try that work around yet, does it disable the notification for both 30% and 15%?
Got the same problem after Android update (7) erlier this year. All fine with Anroid 6. Extremely annoying. I understand the need to have a notification if you feel so, but there MUST be an option to disable such stupid disinformation. Didn't get any help from my home location therefore writing here. Please, SONY do something, people have been upset for months already as I have learned when seeking for help.
I am very sorry to hear that you feel that way @VerySlow, and please believe me in that we take user feedback very seriously. 
However, in this case the sound notification works as intended, however as I mentioned previously in this thread, I would be glad to forward your thoughts on this internally as user feedback.
@cwarky wrote:Found myself here for same reason but I don't blame the Z5. My phone only started doing this since most recent android update. Longpress on the low battery notification and disable peeking. This can also be found in notification settings for the app System UI
This solution is good enough for me.