My laptop is randomly shutting down when it says it is still at 60-70%?

I own a lenovo z series and when unplugged it works for an hour or and then randomly turns off and then when I turn it back on it says that it has 0% remaining please help

Guest

Assuming battery is working, then the main problem is known as calibration problem, meaning the battery has forgotten where exactly is 0% and 100% points were. This is the usual cause for issues relating to showing the correct remaining battery/time. I would recommend to carrying out battery calibration in according to your laptop manufacturer.
http://allbestlaptop.com/laptop-battery-percentage-always-100/

TvT