PaulS did a great write-up called TC: The Quick and Dirty
and gave me permission to post it here in the FAQ. If you have any questions or comments, you can post it on the original thread by clicking the link above.
Lets go over temperature sensing and the various coils and TCR settings and what they mean.
Metals used for coils:
-- a ferritic iron-chromium-aluminum alloy specifically created for stable resistance at varying temps. Used in power mode primarily but now some modes have temperature sensing for kanthal.
—is made from nickel chromium alloy and has a lower maximum operating temperature than kanthal. This means it heats up faster than kanthal and is great for cloud chasing. It has a lower resistance than kanthal. It can be used for TC vaping with a DNA200.
— used in TC mode because it predictably changes resistance with change in temperature. Can produce harmful nickel oxides at high temps, and must NOT be used in VV/VW mode.
—used in TC mode because it predictably changes resistance with change in temperature. Can produce harmful titanium dioxide at high temps, and must NOT be used in VV/VW mode.
— smaller change in resistance with change in temperature (compared to Ni and Ti), so not supported in TC on some devices, but safe to use in VV/VW as well, making it the most versatile. Comes in many alloys/grades, with 304 and 316L being among the more commonly used in vaping. SS does not oxidize. This has about half the resistance of Kanthal so if building with SS wire be aware of that.
Common wire configurations:
-- just like it sounds.
-- two or three wires twisted together, which lowers resistance and increases surface area (giving more juice contact).
-- a thinner wire wrapped around a core (or a 2-wire core, in the case of a fused clapton) for increased surface area
The hotter the wire, the more resistance it will generate.
Resistance is affected by volume, diameter, and the length of wire. Thinner wire has higher resistance than thicker wire. You can think of it like a highway: The bigger the highway (thicker the wire) The easier it is to move through it (lower resistance). The longer the wire, the higher the overall resistance. Here is what we mean: Nichrome 80 Resistance wire has a lower resistance per length compared to kanthal, meaning it will heat up faster; better for those sub-ohm builds and cloud chasing.
Using your coils on a TC mod
You must enter TC mode to use TC coils. You can then choose NI or TI or SS. There are a few mods that are temperature sensing that can use TC with Kanthal or Nichrome. You set your values in TCR mode. When I cape SS 317L for instance I go to TCR mode. You cannot cape TI or NI in power mode. It is dangerous. There is no recommended temperatures for TC. You have to dial in your preferences. They generally range from up to 300 c and 600F. But never go above 580F. You are getting into a dangerous zone for oxides. There is a misconception that kanthal and nichrome cannot be vaped in a temperature sensing mode. Ijoy has mods that can sense kanthal in what is almost a TC mode. The Hohmwrecker G2 mod can be set in TCR for kanthal. So it is possible. But don't attempt it until you understand it.
These are temperature coefficients that certain mods will allow you to use. When caping SS in TC I find i need to adjust the TCR because its resistance does not change as much as NI or TI. So I modify to taste and reduce the temp as well to about 50 degrees. Temperature Control works by monitoring changes of resistance in the coil and using this to estimate temperature changes. Resistance increases linearly and predictably with temperature, although the amount that it increases varies between wire types. So preset TC settings can work but sometimes you need to use TCR settings and adjust.
TC is possible only with wire that has a reasonably high Temperature Coefficient of Resistance (TCR). The Coefficient is a numerical value that indicates how much resistance will rise for a given temperature increase relative to its starting resistance. When the coefficient is high resistance will increase a lot as temperature increases. When it is low, resistance rises a smaller or negligible amount.
The TCR is relative to the starting resistance. This is why we lock in the resistance. The higher the starting resistance of the coil, the greater rate of increase in resistance with temperature.
Stainless Steel 304L
Stainless Steel 316L
Stainless Steel 317L
Get TCR settings here for your DNA200 … steam-engine.org
The conception held by numerous indivisuals is that TC is for newcomers to prevent 'dry hits'. TC settings are temperature limiting but certainly not perfect in that regard. Advanced users feel they can handle power mode without getting a dry hit. However using TCR on advanced mods will get you a superior vape now. It takes some customization for TC to work effectively. When you get it right though the taste and the warmth of your vape can be set precisely to your likes. It isn't really just for 'dry hit' protection. It is for beginners but advanced users will use TC to get just the right vape for them. On a Hohmwrecker G2 I can set kanthal for the perfect vape with a little experimentation and a lot of patience. But once it is set it is better than power mode.
TCR is now used for Nichrome, Kanthal, Platinum, NI, TI and combinations of different wire in claptons and aliens. It is quite complicated and takes some practice and experimentation. It certainly is not for everyone. Now I am a mech guy primarily but I have a number of regulated devices and use TCR at times with my RDAs and often with my tanks - unfortunately some mods do not regulate TCR as well as others. But the ones that do are marvelous.
Well that is just about it. Check out the original post
if you have any questions and want to know more.