Hi Joey...I want to first congratulate you on making the switch to vaping and welcome you to Vaping Underground! I tell this to everyone new but it's true, this is the best and friendliest forum on the web and if I can't help you here someone will and I hope you enjoy vaping and your time around here.
Now onto the important matter at hand...you are right about the Istick running hot...most people I've read can't run coils higher than the 12-14 watt setting without burning out their coil. Just a reference point to keep in mind...it sucks I know. As for the coil itself...once you get that "burned' taste you'll never get it out...the coil is done. This also sucks, I am sorry but that's all there is too that....
On the question of how long a coil will last the answer is every coil's mileage will vary...Those suckers are mass produced by the million and there are going to be a few bad ones that burn out quick or DOA and others that last weeks or even months. It's just the way it is...and yes the juice can make a difference. Higher VG ratio juices take longer and wick slower so if you chain vape long drags back to back for several vapes you can dry out the wick quickly and it can take awhile to get good and soaked again...50/50 shouldn't shouldn't give you any grief though, maybe a little if you have a serious chain vape session but that is about it....however the quality and flavor of the liquid can make a difference... not nessacarily cheaper, but low quality liquids as well as dark or sugary liquids can clog up the filler material that wicks the coil faster then clear or lighter colored liquid or a higher quality liquid in general...the sugars in sweet vapes especially. The filler material that wicks the coil also acts kind of like a filter and it gets clogged over time, kinda like a fuel filter in a car...eventually it gets clogged enough that it can't feed the coil properly and the coil in turn dries and burns the filler ruining the coil head. The higher the wattage you run them at the faster it can burn them out as well from having to wick more juice to keep up speeding up the clogging process. These coil heads are designed like old school cartomizers and they had the same problem.
One way you can help keep your coil going is when you put a fresh one in or every other fill or so drop a drop or two of liquid on the fill ports in the side of the coil assembly...if the filler is dry it will literally suck the liquid into the coil filler and cut down on the amount of time you have to let a new coil sit and soak before you can vape it, on a used coil if it doesn't suck the liquid in then either the coil is good and wet, or it is starting to get clogged...you'll know by taste as usual.
One thing you can do is go back to your old set up for a couple days and see if the coils are burning out as fast now on the old set up as they are the Istick....if the coils burn out just as fast then you'll know it's the pack of heads you got...if they last longer then maybe play with the wattage on the Istick or try another juice and see if you get more life out of them....
Good luck and I am sorry if this is not of any help. And happy vaping!
