Low volt single 18350's won't fire, but fire when stacked?

[michliu]

This is my first experience with 18350's. The Efests won't fire when they hit 3.4v in single mode. But if I stack 2 18350's that have run down, the Vamo fires again showing 7.6v and I can get another couple of hours of vaping. When they run down to 6.4v they also stop firing. Is this normal for 18350's?

 

[tc1]

That is normal but make sure you pair your batteries when stacking. Using 2 18350s at different charge/voltage levels can be dangerous.