i have a problem.... my n900 is consuming about 30%battery @ reboot

for exsample.... i have about 60% battery left then i have to reboot or my n900 crashes and reboots and then my battery is almost empty....

this week i was listening musik.... and i had about 50% left... then i accidently turned of my n900.... startet it again.... and then it said battery empty....

about 10 min ago it crashed.... before the crash i had exact 69% and then after reboot i have only 15% left....

i dont think it is my battery because i ve 3 batteries and with all of them i ve the same issue....

thx for hlp...

greetz