Hi,

I'm using OpenBSD on a laptop.  I'm also using battery-mode.  Whenever,
I'm accessing another machine over TRAMP, the string displayed by
battery-mode become useless in this buffer.

The attached patch fixes this issue.  AFAIU, shell-command-to-string is
using the current directory of the buffer and fails to find a usable
"/usr/sbin/apm" on a remote Linux, for instance.  So I'm using
call-process that does call the local "/usr/sbin/apm".

Best regards,