1st I'm of the crowd that only uses as much power as needed to get the coil hot within what I consider a reasonable amount of time. The SX displayed temperature will fluxuate wildly if the power is set to high.
I'm also a bit of a "toodle puffer" and rarely if ever use more power/joules than 25W/J. Your mileage may vary if you like to crank the settings up to the maximum. (the SX mini has a number of preheat fixed settings that can be of use) Last but not least, I also tend to push the limits of how HIGH of a resistance a coil can be and still be temperature regulated. Point being that for the same wire type and TCR, a higher resistance wire will have a greater resistance change from room temperature to vaping temperature than a lower resistance wire will.
(I've vaped 2.1ohm SS430 coils on my SXminiM in Joules/TC mode without issue. Not many mods will do that. The VT-Mini's upper limit is said to be 1.5ohms?)
Not all wire types are created equal. It depends on the supplier. I order NiFe wire from Germany for this very reason. The Ti01 and SS430 wire I use I get from
UnkamenSupplies)
With all that said - there are two tests that a user can do to check the accuracy of their mod+TCR+wire.
- the cotton burn/singe test: what temperature setting will discolor your cotton wick? (dry fire for up to a minute or two)
- the water test: funny thing about water, it boils at 212F and as long as there is water to boil, chances are your mod will be stuck at 212F until your wick starts to dry. This is best done with a RBA, RTA or RDA so you have an open deck, a single coil and your wick exposed. Personally I like doing it in the kitchen sink with the water running.
WARNING: getting water inside of your mod is very very likely not a good thing. Be careful.
After getting the coil built and the resistance locked in, I'll wick like I normally would and I'll head for the sink and SOAK the wick with tap water. Fully drenched. The ends that would normally drop into juice channels I'll try to put over the coil leads. A wick that is DRENCHED with cold H2O (water) will be difficult for your mod to overwhelm, especially if you keep your wattage setting low - like 10-20W.
Once soaked and the leads covered with wick I'll watch the screen while firing the mod. Not all mods will give you a real time display of the wire's temperature but the VT-Mini will. Its not always an "exacting science" and the displayed value will "hover" up/down over an average value that the user can then observe.
Sometimes it takes only 1-5 seconds, others longer than that. Remember to add water to the wick if the value starts climbing up hotter.
Some mods will hold a fairly steady value for 5-10 seconds. If the value is within 5F (or less) of 212F (or exactly 212F) then whatever pre-programmed or user entered TCR value entered for the wire type in use is correct.
I usually fire - douse - repeat several times to get a good feel as to the temperature value.
If the displayed temperature value is to low (lower than 212F) your TCR is to high or large of a value and needs to be reduced.
If the displayed temperature value is to high (higher than 212F) your TCR is to low or small of a value and needs to be increased.
My 1st "TCR" adjustable mod (an Apollo Reliant) is unable to use the "standard" published values for different wire types so I got in the habit of water testing and then dry burning each different wire type before using it with my juice. (yes, I know "thebloke" posted some calculated numbers that are fairly close but he never actually tested many of them)
I now have the Reliant, two differnet SX350J's (SXminiM and Boxer350Jv1) and two VT-mini's to compare with. (a cubiod is on the way)
Personally if I'm getting a "lame vape" and don't know if it is my build, wicking, juice or wire/tcr/mod I'll drain the tank, expose the coil, soak it in water and then see for myself what the problem might be. (since I'll likely rewick anyway I don't much care if I soak it in tap water)
Personally I believe that the "hot" and "cool" qualities of different mods relates more to how well (or not) they read the base resistance of your build.
g.