Also stacking batteries is a potentially good way to turn your mod into a pipe bomb that could blow your face off. Sorry to be a tad harsh but I wanted to drive the message across so you vape safely, don't get injured and don't end up banning
vaping for the rest of us if you do get hurt.
Those batteries are officially trash. Buys some more AW IMRs but this time buy 18650s which will last much longer per cycle. Never let them get below 3.3v before charging them and they'll last quite a bit longer too. Over discharging batteries isnt a good idea and may lead to bad things. Luckily AW IMR batteries do have safer chemistry so the likelihood of one blowing up on you is significantly reduced but still. Stacking batteries OR over discharging them are each no no's. Combined is a tremendously huge NO NO.
In short:
1) NEVER EVER EVER STACK BATTERIES!!!!
2) NEVER LET BATTERIES DISCHARGE BELOW 3.3v (I'm sure others might say an even higher minimum voltage before charging).
-if they discharge as far as yours have dispose of the appropriately and don't think twice about it.
