Currently there are 2 patches (EU only):
Battery percent in status bar (statusbatpercent)
This patch replaces date in statusbar with battery percent. It is not possible to display "%" character, so it shows battery percent as ":35:" instead.
Battery icon in status bar with 25% bars (statusbaticon)
This patch makes the battery icon display each bar as 25% of battery charge.
It needs Luma3DS with game patching and optionally exheader patching from latest release (otherwise you need to patch SM checks on each boot).
It is only available for EU home menu as that is what I have, but it can be easily ported to other regions.
Download: https://github.com/nowrep/3ds-patches/releases
Battery percent in status bar (statusbatpercent)
This patch replaces date in statusbar with battery percent. It is not possible to display "%" character, so it shows battery percent as ":35:" instead.
Battery icon in status bar with 25% bars (statusbaticon)
This patch makes the battery icon display each bar as 25% of battery charge.
It needs Luma3DS with game patching and optionally exheader patching from latest release (otherwise you need to patch SM checks on each boot).
It is only available for EU home menu as that is what I have, but it can be easily ported to other regions.
Download: https://github.com/nowrep/3ds-patches/releases