few days ago I had my n9 discharge 40% within 8 hours with sitting idle in my pocket, only GSM at use so no extra powerdrain... nothing to find from the system so it must be a stuck hardware as it kept discharging at this rate even in flightmode... powercycling helped... third time this year I had to (in terms of some stuck stuff forced me to). Did you install any services lately? And for the records, we managed to drain more juice from n900s than its charging logic could provide on one of the PRs (iirc).