-(defun ff/battery-percent ()
- (/ (* 100 (string-to-number (ff/file-first-line (concat ff/battery-dir "/charge_now"))))
- (string-to-number (ff/file-first-line (concat ff/battery-dir "/charge_full")))))
+(defun ff/battery-percent (prefix)
+ (condition-case nil
+ (/ (* 100 (string-to-number (ff/file-first-line (format "%s/%s_now" ff/battery-dir prefix))))
+ (string-to-number (ff/file-first-line (format "%s/%s_full" ff/battery-dir prefix))))
+ (error -1))
+ )