Here are my batteries, bottom one with more info there is the most recent one. Does it look ok?
Battery 1 (top) looks double wrapped, it 'Might' be ok, battery 2 (middle), ugh, what did you do to it, poor thing, battery 3 (bottom) looks a bit more safer battery wrap wise. The light green wrap I am seeing on all 3 are kind of reminiscent of the wrap on the Samsung 25R Rev 5 (this is the latest version of the 25R). All things equal, I am going to have to agree with
@Coastal Cowboy and you need to re-wrap them batteries, especially battery 2, that or recycle them entirely. Guessing, and I mean guessing, just by the wraps and the 2500mah rating, those are most likely Samsung 25R batteries, though can not say if they are A, B, or C Bin quality being re-wraps, the Samsung 25R is a 20amp Continuous Discharge Rated (CDR) battery, as posted above given your Smok control board, you are almost 22amps at lowest battery charge for that mod.
50watts Max - Samsung 25R (buy the real one not a re-wrap) will still suit you well, you can run it at 55watts but as you are noticing, after a bit the battery sag is to much the mod is kicking in its low voltage protection on you.
65watts Max - the Sony VTC5A or the LG HD series I listed above
80watts Max - then you are looking at the LG HB2, HB4, HB6 1500mah 30amp CDR batteries for it.
And please for the love of god for your batteries, just by them wrap pictures above "DO NOT FORCE A BATTERY INTO A BATTERY SLOT IN A MOD", which is what looks like happened with battery 2, another thing is to check the battery slot in the mod for any machining burrs and such, there should be no reason other than negligence for a brand new battery (silver label on battery 3) to be showing damage to the battery wrap already unless it is internally in the mod that is causing it. If it is not in the mod then it is in how you are storing and transporting your batteries, if in a pocket, your next battery purchase you need to purchase at least a 2 bay battery case to transport and store your batteries in. Hate to sound harsh and harping, but geesh, a little common sense, especially when dealing with an item like a battery that could potentially go off like a 1/4 stick of dynamite if handle inappropriately.