I don't think this is the problem. Most of the time acpi_listen gives me only:
battery PNP0C0A:00 00000081 00000001
battery PNP0C0A:00 00000080 00000001
battery PNP0C0A:00 00000081 00000001
battery PNP0C0A:00 00000080 00000001

and in some extremely special cases which I can't reproduce:
battery PNP0C0A:00 00000081 00000001
battery PNP0C0A:00 00000080 00000001
ac_adapter ACPI0003:00 00000080 00000000
processor LNXCPU:00 00000081 00000000
processor LNXCPU:01 00000081 00000000
battery PNP0C0A:00 00000081 00000001
battery PNP0C0A:00 00000080 00000001

which should be like that all the time.
I think it's a hardware problem or a problem with the adaptater itself.
Anyway, I can easilly resolve this problem by doing something like this instead of basing the script over the ac_adaptater base it on the battery:
battery)
case "$2" in
BAT0)
case "$4" in
00000000)
logger 'Battery online'
echo -n $maxspeed >$setspeed
;;
00000001)
logger 'Battery offline'
echo -n $minspeed >$setspeed
;;
esac