What the heck is going on with my batteries?

[WarHawk-AVG]

I bought 2 TrustFire 18350 protected on Ebay & loaded them into my Vamo V3. Found that they only work properly when stacked. When using only one (fully charged), they shut the Vamo V3 off when I press the 'fire' button. When I stack both batteries (must remove the Vamo battery spring to do so), they work just fine.

Been there, done that bud...
http://www.e-cigarette-forum.com/fo...05-yet-another-vamo-v3-thread-one-review.html
IMR's in a Vamo...it has built in protection circuit in the control head....batteries with the protection circuit heatshrunk to the battery are ICR's...

http://www.e-cigarette-forum.com/forum/ecf-library/129569-rechargeable-batteries.html