You hook up a volt/ohm meter is the best way, anything under say 2ohm is an LR, if your running them higher then say 4.2v you have more risk of popping them, however your probably popping them because you not keeping them nearly wet enough, if your using carts try switching to a dripping tip, until you have a dripping tip pull off you stock cart and drip 6-7 drops in at a time and
vape, the second you flavor or vapr drops off drip again, these need to be kept wet, very wet, they burn much hotter then a regular Atty does and will also run your batt down quicker, they draw more like 2amps instead of 1amp like a reg Atty does too.!!
Hope that helps ya out a bit Karen, also you should be using a 450mAh Batt or higher with LR's