The NL186 is an okay flashlight battery but shouldn't be used for
vaping purposes.
It is a low amp/CDR protected button top cell.
Nitecore advertises it as " high output current
up to 4a ".
Your power
device requires IMR/INR chemistry high drain battery with a sufficient CDR to power it safely, (20a CDR minimum).
While you may have stuffed a button top battery in, the evic vtwo is designed to use flat top cells.
LG HG2 3000mah 20a
Samsung 30Q 3000mah 20a
AW 3000mah 20a
Only buy
batteries from reputable vendors / dealers to avoid recieving lesser quality, rewrap erroneously labeled or counterfeit cells.