I have a HP Envy 15t 3200 notebook (bought summer 2012). The battery has only 191 charge cycles out of 600 on it, because I nearly always use the notebook while plugged in.
The past few weeks, if I run the computer on battery power for more than an hour/90 minutes or so, it will suddenly and without any warning at all go dead.
-No low battery warning (I have the low warning set at 12% remaining and critical warning/hibernate at 7%)
-When I plug it back in and boot up, the battery is nowhere near dead (35-45% remaining)
-No shutdown/suspend procedure at all-it just goes black and dies.
-When it shuts off, the fan is always running, but that is not unusual.
-When it shuts off, CPU temps are well within normal range (I have a temp monitor running in the sys tray)
-Not running anything besides word/outlook/browser. Nothing new, unusual, or particularly demanding.
-Have not installed anything lately, except for the usual adobe reader/java/windows updates.
-Ran both battery tests (HP System Diagnostics and HP Support Assistant) and both passed. All battery cells read about the same voltages.