-;; Either BATn or yeeloong-bat, basically.
-(defconst battery--linux-sysfs-regexp "[bB][aA][tT][0-9]?$")
+(defcustom battery-linux-sysfs-regexp "[bB][aA][tT][0-9]?$"
+ "Regexp for folder names to be searched under
+ /sys/class/power_supply/ that contain battery information."
+ :version "25.2"
+ :type 'regexp
+ :group 'battery)