bluetooth does not start when battery bower on hp-630 notebook

when on battery power bluetooth indicator light is blinking and cannot turn on bluetooth.
But in AC power It works correctly.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: acpi 1.6-1
ProcVersionSignature: Ubuntu 3.2.0-30.48-generic-pae 3.2.27
Uname: Linux 3.2.0-30-generic-pae i686
ApportVersion: 2.0.1-0ubuntu13
Architecture: i386
Date: Sun Sep 16 10:27:42 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
ProcEnviron:
 LANGUAGE=en_US:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: acpi
UpgradeStatus: No upgrade log present (probably fresh install)