Sony h.ear on 3 Mini Wireless Help Manual page 18

You can also check the remaining battery charge with the "Sony | Headphones Connect" app. Android smartphones and
iPhone/iPod touch both support this app.
Note
If you connect the headset to an iPhone, iPod touch, or Android smartphone with "Media audio" (A2DP) only in a multipoint
connection, the remaining battery charge will not be displayed correctly.
The remaining battery charge may not be properly displayed immediately after a software update or if the headset has not been
used for a long time. In this case, repeatedly charge and discharge the battery multiple times to properly display the remaining
battery charge.
Related Topic
What you can do with "Sony | Headphones Connect" app
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