Because the return value of `pmset' on Mac OS X Mavericks changed, If you evaluate (display-battery-mode 1), the following error occurs.
`wrong-type-argument number-or-marker-p N/A'.
I made a patch for this issue.
Thanks for reading.
--
Masashi Fujimoto
--- battery.el 2013-01-02 05:37:17.000000000 +0900
+++ mavericks-battery.el 2013-10-23 12:11:13.000000000 +0900
@@ -543,7 +543,7 @@ The following %-sequences are provided:
(with-temp-buffer
(ignore-errors (call-process "pmset" nil t nil "-g" "ps"))
(goto-char (point-min))
- (when (re-search-forward "Currentl?y drawing from '\\(AC\\|Battery\\) Power'" nil t)
+ (when (re-search-forward "\\(Currentl?y\\|Now\\) drawing from '\\(AC\\|Battery\\) Power'" nil t)
(setq power-source (match-string 1))
(when (re-search-forward "^ -InternalBattery-0[ \t]+" nil t)
(when (looking-at "\\([0-9]\\{1,3\\}\\)%")