Lenovo k 900 battery draining fast?

Question

Rechargeable batteries

Good afternoon!
phone: Lenovo k 900 32gb
OS: Android 4.2
One fine day (as it happens) the battery started to drain quickly. By fast, I mean up to 45% in 1 hour on the Internet or in the game. In standby mode for a day (with Wi-fi and the Internet turned off, of course).
The conclusion is obvious replacement of the battery, but only replaced and the situation is the same.
Please advise what could be the problem? Thanks in advance!