This question already has an answer here:
When I shut down(not sleep or standby or hibernate) the computer the is at 80%. Next morning I tried open my laptop it didn't start without plugging the ac power because the battery level is 0%. I'm sure its not my battery problem because its giving 3 hours of backup on 80%(battery life cycle extension) only and I calibrated my battery too.
I bought my laptop last year. My laptop is Samsung series 3 np350v5c Windows 7 home premium 64-bit and 8 gb ram installed. I just wanna know why this happened and a solution of course.