Startup w/o acpi modules for batt and ac:
root@jkd:~# time /etc/init.d/dbus start
 * Starting system message bus dbus                                                                          [ OK ]
 * Starting Hardware abstraction layer hald                                                                  [ OK ]
 * Starting DHCP D-Bus daemon dhcdbd                                                                         [ OK ]
 * Starting network connection manager NetworkManager                                                        [ OK ]
 * Starting Avahi mDNS/DNS-SD Daemon: avahi-daemon                                                           [ OK ]
 * Starting network events dispatcher NetworkManagerDispatcher                                               [ OK ]

real    0m6.661s
user    0m0.169s
sys     0m0.097s




root@jkd:~# modprobe ac
root@jkd:~# modprobe battery
root@jkd:~# time /etc/init.d/dbus start
 * Starting system message bus dbus                                                                          [ OK ]
 * Starting Hardware abstraction layer hald                                                                  [ OK ]
 * Starting DHCP D-Bus daemon dhcdbd                                                                         [ OK ]
 * Starting network connection manager NetworkManager                                                        [ OK ]
 * Starting Avahi mDNS/DNS-SD Daemon: avahi-daemon                                                           [ OK ]
 * Starting network events dispatcher NetworkManagerDispatcher                                               [ OK ]

real    1m10.391s
user    0m0.261s
sys     0m0.149s






And this is what syslog says:
Mar 31 01:17:06 jkd hald[8852]: 01:17:06.499 [I] acpi.c:1225: acpi_add: acpi_path=/proc/acpi/battery/BAT0 acpi_type=0, parent=0x00000000
Mar 31 01:17:44 jkd hald[8852]: 01:17:44.505 [D] acpi.c:162: Current voltage is unknown, smaller than 501001765435r greater than design
Mar 31 01:17:44 jkd hald[8852]: 01:17:44.519 [I] acpi.c:1197: Add callouts completed udi=/org/freedesktop/Hal/devices/acpi_BAT0
Mar 31 01:17:44 jkd hald[8852]: 01:17:44.520 [I] hald.c:106: Added device to GDL; udi=/org/freedesktop/Hal/devices/acpi_BAT0
Mar 31 01:17:44 jkd hald[8852]: 01:17:44.520 [I] acpi.c:1225: acpi_add: acpi_path=/proc/acpi/processor/CPU0 acpi_type=1, parent=0x00000000
Mar 31 01:17:44 jkd hald[8852]: 01:17:44.534 [I] acpi.c:1197: Add callouts completed udi=/org/freedesktop/Hal/devices/acpi_CPU0
Mar 31 01:17:44 jkd hald[8852]: 01:17:44.534 [I] hald.c:106: Added device to GDL; udi=/org/freedesktop/Hal/devices/acpi_CPU0
Mar 31 01:17:44 jkd hald[8852]: 01:17:44.534 [I] acpi.c:1225: acpi_add: acpi_path=/proc/acpi/ac_adapter/AC acpi_type=3, parent=0x00000000
Mar 31 01:18:05 jkd hald[8852]: 01:18:05.011 [D] acpi.c:162: Current voltage is unknown, smaller than 501001765435r greater than design
Mar 31 01:18:05 jkd hald[8852]: 01:18:05.055 [I] acpi.c:1197: Add callouts completed udi=/org/freedesktop/Hal/devices/acpi_AC
Mar 31 01:18:05 jkd hald[8852]: 01:18:05.055 [I] hald.c:106: Added device to GDL; udi=/org/freedesktop/Hal/devices/acpi_AC
Mar 31 01:18:05 jkd hald[8852]: 01:18:05.056 [I] acpi.c:1225: acpi_add: acpi_path=/proc/acpi/button/lid/LID acpi_type=11, parent=0x00000000
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.071 [I] acpi.c:1197: Add callouts completed udi=/org/freedesktop/Hal/devices/acpi_LID
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.071 [I] hald.c:106: Added device to GDL; udi=/org/freedesktop/Hal/devices/acpi_LID
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.071 [I] acpi.c:1225: acpi_add: acpi_path=/proc/acpi/button/power/PWB acpi_type=11, parent=0x00000000
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.086 [I] acpi.c:1197: Add callouts completed udi=/org/freedesktop/Hal/devices/acpi_PWB
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.086 [I] hald.c:106: Added device to GDL; udi=/org/freedesktop/Hal/devices/acpi_PWB
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.086 [I] acpi.c:1225: acpi_add: acpi_path=/proc/acpi/button/power/PWRF acpi_type=11, parent=0x00000000
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.100 [I] acpi.c:1197: Add callouts completed udi=/org/freedesktop/Hal/devices/acpi_PWRF
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.101 [I] hald.c:106: Added device to GDL; udi=/org/freedesktop/Hal/devices/acpi_PWRF
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.101 [I] acpi.c:1225: acpi_add: acpi_path=/proc/acpi/button/sleep/SLPB acpi_type=11, parent=0x00000000
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.116 [I] acpi.c:1197: Add callouts completed udi=/org/freedesktop/Hal/devices/acpi_SLPB
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.117 [I] hald.c:106: Added device to GDL; udi=/org/freedesktop/Hal/devices/acpi_SLPB
Mar 31 01:18:06 jkd hald[8852]: 01:18:06.118 [I] osspec.c:737: hal_util_find_known_parent: '/sys/block/hdc/fakevolume'->'/sys/block/hdc'


You can see that almost exactly one minute has passed from the first acpi to the last acpi call.