I recently purchased a teclast Air 2 tabelt and found the sleep mode below average. My battery was still draining at a rate not even comparable to my ipad air 2.
Did the “powercfg/energy” command and found the Intel Audio driver didn’t have any mechanism to do a sleep. Then I ran into this article…
http://www.rickygao.com/workaround-for-battery-drain-issue-on-intel-atom-tablet/
I am still testing and it seems to be extending my battery while in sleep mode.
Edwin