This is probably the only thing I dislike about the z2, so I'd love to be able to turn off the LED when charging. To be honest the red isn't so bad, it's the blasted green that turns on when the battery is full.
I emailed Andrew Moore, the developer of the Light Flow app, and he replied:
I've never found a way to supress the charging light when the phone is
on on sony phones (it's the same with the z and z1). I did a little
experimenting with a z and with root it's possible to stop if I think
but before getting chance to experiment more my xperia z died on me
(only 2 days old - not related to my development, but a sim card
reader error) - sony wouldn't replace it as they said it'd cost more
to replace than a new phone so I lost £400 on a dud phone and never
got around to getting another to experiment with. I'm pretty sure
without root it'll be impossible to stop.
I also found something that suggested the Xposed framework included the ability to disable the LED charge indicator.
So at this point we have two options:
1) Wait for Sony to see the light (geddit?) and add the ability to disable the charge LED in a future firmware update (Samsung has this on the Galaxy s5, I noticed)
2) Root, and see if there's some way to disable the LED.
I'm waiting to see what happens with TA backups before I decide to root, so if someone is braver than me and figures things out I'd love to hear about it!
Phone: Nexus 5
Tab: iPad Air
Blog: Is There Food?