TC-TCR Temperature Control TCR Value Solution for Different Coils/Mods

[MTL Connoisseur]

Greetings everyone, First of all I apologize for the possibly long thread but bear with me on this
if you are knowledgeable or interested in the subject. you see it now as is but it took me 2 days to write so bear with me.

For reference I only vape on svoemesto tanks, currently own a Prime and 2 Kayfun lite 2019 one of which is a special edition.
Strictly vaping on Kayfun lite 2019 though, it is perfect.
Here is my current "kit bag" I put together in the past 2 months, minus the Xtar charger and few other things.

My goal is to input a correct TCR for "Any Mod" for each wire spool I own and I only use SS316L Wire 28g and 30g single wire.

I am trying to get the best possible experience while vaping, and I will not put up with incorrect temperatures
because some company decided to save penny's or dollars on their mods to get this measurement correct,
they can test every spool and build in the market and included for us the consumers a booklet with the mod but they chose not to.

I know some of you are happy with Variable Wattage and can put up with a delay if you get dry hit and have to replace
the coil/wick later on not to mention the safety hazard your exposing yourself to, my goal is to have a vape that is accessible/safe/reliable as a cigarette is, a lighter and a smoke and you are done sort of deal, cigarettes are not safe but they are damn accessible and reliable.

I have been vaping for 10+ years on and off and had my shares of provari's and DNA Mods in the past and still have them but I am not using them because they are at a different location currently and the technology has advanced a little since then.
So the setup needs an update anyway.

So I stopped by a local vape shop that has some inventory of mods, the best of wish was a Vaporesso Armour Pro,
I got it along with their classic tobacco e-liquid "Its a vape chain shop that sell their well known brand of e-liquid".
Nothing special about this juice as it is on the sweet side and tends to clog
my coils and turn the cotton black, I have switched to Naked 100 Euro Gold and I am happy with it,
cotton is pure white still after days of almost chain vaping and the brand can be found everywhere.

I been using SS316L "Master of Clouds" wire which is now called "Master Wire Supply",
Been making single 30g coils / 10 wraps / Spaced / 2.5mm internal diameter = 1.45ohm to 1.5ohm
Now if you input these value in Steam Engine you will get the following results:

Heat Flux
200mw/mm "Fahrenheit" @ 16W @4.9V= Natural Vape
210mw/mm "Fahrenheit" @ 17W @5.1V= Warmer Vape
220mw/mm "Fahrenheit" @ 18W @5.2V= Warmer Vape +
230mw/mm "Fahrenheit" @ 19W @5.3V= Warmer Vape ++
240mw/mm "Fahrenheit" @ 20W @5.4V= Warmer Vape +++
250mw/mm "Fahrenheit" @ 20W @5.5V= Warmer Vape ++++ "And considered HOT by the color of the flame on SE"

If you are also wondering why these values do not satisfy you, read on.

The best way to test this I found is before using Temperature Control to use variable wattage and using the 16w
as a starting point and judging by the throat hit you get after few vapes you will know if you switch to
temperature control at 200 Fahrenheit if you are getting close to that heat level or not and if TCR is correct or not, it is as best
as getting close to the ballpark of correct temperature, you might argue that "dry cotton test" is better, well more on that later.

So lets stop there but you get the idea, now if you vape this on the Armour Pro and using 200 Fahrenheit "without 16w VW test"
using their stock TC SS preset for SS316L which has a TCR value of 109 you get very minimal vape almost nothing.
going to 250f on this TCR value also yields minimal gain and it is definitely not as warm as Steam Engine suggests. After looking into this it turns out this TCR value is for Vaporesso coils as this is the standard nowadays for every mod company sets this value to their own brand wires/coils which might be accurate or not, who knows? and which coil type clapton, single, juggernaut, mesh, who knows?

I went to the basics to resolve this issue with inputting the stock SS316L value of 88 TCR based on Steam Engine, this made it
even worse no heat or smoke or flavor at all @ 200F. trying in one increments until I reached TCR value of 141. That
got me as close to the feel of vaping @16w in variable wattage, and going from 200f to 250f felt more true to
the Steam Engine color change for warmth. I settled on TCR-151 for the SS316L 30g by Master of Clouds or Master Wire Supply.

I am trying to quite smoking, I need a backup just in case. So I began looking into what is available now that
is as accurate as possible but also uses single battery and uses 20700 or 21700 battery for its long run time, and easy to carry in pocket.
The best that fits the bill is DNA 75C Mods and there is only a handful of them that fit this specifications.
The best of which is Lost Vape Mirage which as you all know is discontinued for some unknown reason and unavailable except from chinese suppliers and you might receive it or not and then the question of authenticity, I don't want a such a device near me unless it is of known origins and authenticity, I must say most of the mods out there are some of cheapest stuff I have seen, both fit and finish.

The next best thing is YIHI SXMINI SL CLASS which is on it's way, although known for better accuracy I am sure I will run into TCR
issues and dialing in this brand of wire or any other brand of wire and mod combo to the correct value.

I am still concerned on the high TCR value of Vaporesso Armour Pro and possibly the same for YiHi that is on the way.
After researching I came across this invaluable study that I think everyone using or interested in temperature control should read throughly
Measurement of heating coil temperature for e-cigarettes with a “top-coil” clearomizer
What you should really know is that temperature of the coil was tested in 3 configuration:

1.1 Dry condition–Coil temperature was measured in the absence of any test liquid
"a.k.a dry cotton test"

1.2 Wet-through-wick condition–The clearomizer was filled to 1.6 mL without directly dripping liquid on the heating coil; after ≥30 minutes of wick wetting.
"This is found to be the best method to take temperature and it simulates real life conditions plus I suspect it is Steam Engine
heat flux should be based on this temperature"

1.3 Full-wet condition–The clearomizer was filled to >2.3 mL, i.e., the entire coil was in direct and full contact with the liquid.

From the graphs you will see how the dry condition really gives very high temperature which is significantly different and higher than wet-through-wick and full-wet condition.

So I don't understand the dry cotton test method nor should it be used as base of temperature,
For safety maybe for accuracy definitely not.
Based on the study above:

Under full-wet conditions: (110 to 185°C) 230F-365F the difference= 135F
Wet-through-wick= (145 to 334°C) 293F-633F the difference= 340F
Dry Coils: (322 to 1008°C) 611F-1846F the difference= 1235F!!!

Same power and conditions, in a lab environment and this is the results.
So unless you are spot on and "capturing that 322c every 4 seconds pulse" and getting just right and perfect every time
or you are thrown to any random numbers between 322 to 1008°C in dry condition. or 0-1008°C for that matter as I know someone might suggests we are not testing dry cotton 322c but only at 400F well that is even worse look at the "Max's" above 185c,334c,1008c!
no human can be that accurate and you are not vaping on dry cotton, your test should be based on wet-through-wick.

Dry cotton testing you are firing the coil at 400F for 2-4 seconds and off to check if you got browning,
well you might have just hit 500F-600F for fraction of a second and not realise it "look at the gap above
611F-1846F= that is a 1235F difference, you are guessing at best and you are not accurate.
From the study:
"Our previous study under controlled heating temperatures using a tube reactor demonstrated a very rapid increase of carbonyl emissions as heating temperature increased above 270°C (e.g., from 0.96 ± 0.35 μg formaldehyde/ml-liquid at 270°C to 5.47 ± 0.72 μg formaldehyde/ml-liquid at 318°C for 1:1 PG/GL) [7]. This may explain why large formaldehyde emissions were always detected at higher voltage/applied power (e.g., ≥ 9 W). The results in published studies (see S1 Fig) differed substantially at lower voltage/applied power (e.g., 4–6.5 W). Our results suggest that high temperatures (e.g., up to 276°C for a HR coil at 4 V) were possible even at low voltage/applied power due to temperature non-uniformity and performance variation among different coil heads."

At best a dry cotton test will tell you it is safe to vape at this TCR level but then you will not be satisfied with the vape and will crank it up to 300F-400F+ to make up for huge difference you see in the study above. If your TCR was set correctly, you will not want to pass 300F no matter how heat-proof your throat is lol

Right now for me at least SS316L 28g spaced 1.24ohm is giving me an excellent vape at TCR-141
the SS316L 30g spaced 1.5ohm runs better at TCR-151. My temperature are between 200F and 250F and I am a 1 pack+ cigarette smoker.

I have ordered Digital Thermocouple Temperature Thermometer and these temperature probes to test each coil at my preferred build using wet-through-wick method with each mod I own now and in the future to get the correct TCR value, no matter if it is a DNA or not.
https://www.amazon.com/gp/product/B071V7T6TZ/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0142RXG84/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B01MU29Q3Z/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

I post this thread to get your feed back and to start a discussion about this topic, please feel free to contribute and share your findings
or what have been stated above. Again I do apologize for this long thread, you see it now as is but it took me 2 days to write.

 

[Fredman1]

Interesting. I'm eagerly following this thread. This is @mikepetro territory.

 

[mikepetro]

Mike Petro's Blog Index | E-Cigarette Forum

Start with this to see my methods.
Real Life temp measurements inside a 2016 era atty | E-Cigarette Forum

Then read these articles for more thought provocation:
VV & VW Mod Temperature Variables | E-Cigarette Forum

The basics of getting the most accuracy out of your TC Mod | E-Cigarette Forum

Then browse through some of my other blog posts for more info.

 

[Punk In Drublic]

@MTL Connoisseur – that is quite the post

Steam Engine Heat Flux is calculated as 1 watt/coil surface area. The math is correct, but the value is meant to be a guide and not taken as gospel. It is impossible for Steam or any other calculator to factor in the many variables on how e-juice and air flow influence the heat of the coil.

The scientific study you linked also does not account for airflow, therefore its findings are incorrect.

Agree on the TC accuracy of many devices. But do not understand where you are getting 200°F from. If that is taken from Steams Heat Flux, that is not how the value is used. Heat Flux is a measurement of milliwatts per millimeter squared, it is not a measurement of Fahrenheit. 16 watts with a 200mW/mm² means at 16 watts, your coil is generating 200 milliwatts for every square millimeter. The little coloured flame icon is meant as a easy to understand guide to allow you to compare 2 or more different coils. It does not have any static value other than to indicate coil A maybe a little warmer than coil B for a particular power setting. And as mentioned above, it does not factor in the influence air and juice has on the coil.

 

[mikepetro]

I did my studies about a year before the Yong Wu study on PLOS. The difference in my studies was that I actually vaped the test samples under real world conditions (while measuring) and could therefor give subjective observations in addition to the accurate instrumentation.

• Yong Wu's study had a few flaws, he was using VW gear, and he was not actually taking a puff off the atty during measurement, among others. Airflow is a HUGE and important variable! A lot of his observations, and mine, can be explained in my VV/VW Variables chart.
  
• I totally agree that a dry cotton test is not an accurate method of measuring temperature. It is at best a crude approximation of a single data point.
• I agree that coils dont generate uniform heat across their length. Thats just the physics of our process. A TC Mod is measuring the hottest point in the coil, usually the middle but it could also be a hot spot. I build my own TI clapton coils in my DNAs. They do suffer from hot spots occasionally.

The goal of wanting the exact same vape from multiple Mods/Attys is a desirable one, but it has to be tempered with reality. In a laboratory most variables can be precisely controlled if the variables are known. In the real world it is not likely the case. You can get pretty close in the ballpark, but expecting "precise" replication is a challenge.

• Lets talk about TCRs. Unless you have a lot of fancy lab equipment you cannot measure the TCR yourself. Charts and tables like SteamEngine use calculated values, and/or manufacturer reported values. Depending on the MFG there could be variations even within the same spool of wire. Slight variations in the metal alloy mixture, and the precision of the wire diameter can lead to resistance differences.

OK, now lets look at doing your own measurements. IMHO your choice of thermocouples will give you an undesirable lag in measurement. You will hit a peak temperature in the Mod before the thermocouple has a chance to register it. The metal sheath on the first one will be next to impossible to get inside an atty and still vape. If you arent replicating the airflow through the closed chamber of your atty then your results will be useless in comparison to real life. You will get the fastest response from very fine diameter thermocouples. I like these in a 30AWG diameter. Also, I never had much luck with the SS braid jackets, they increase the diameter (3mm is huge in this application) making it hard to get the probe/wire in an atty and still be able to button the atty up. I landed on Kapton insulated probes as they are very fine and easy to snake into an atty. They limit you to 500F but you dont want to vape at/above that temp anyway.

• Remember, that differences as low as .001 ohms in your coil/mod/atty can and does make a difference in the extrapolated temperature measured.
• One factor often overlooked is the resistance of the Mod itself. See this for more detailed info: The basics of getting the most accuracy out of your TC Mod | E-Cigarette Forum. This means 2 different mods can behave a little differently, even with exact same atty/coil. I dont know about the Yihi stuff, but I am intimately familiar with the DNA line. You can get a copper bolt with 510 threading to dead short the 510 and then read the Mod resistance through eScribe to accurately set this on a DNA Mod. This measurement should not be underestimated if you are looking for accuracy.
  
• IMHO the only way you can get two Mods to vape identically is they are both the same model, made by the same person. I make all of my own mods and mine generally come to .006 ohms. The quality of the 510 connector is also a huge contributor to accuracy. Some have springs that are too weak and cause a variation in resistance.
  
• IMHO saying "they can test every spool and build in the market and included for us the consumers a booklet with the mod" is an unrealistic expectation. Can they do a better job, yes, can they meet the ideal you propose and still stay in business, I doubt it. Too many wires/attys/builds to make this realistic. Besides, the job of specifying the TCR belongs to the wire MFG, not the Mod MFG. The TCR is a spec of the wire ONLY and is irrespective of the Mod/Atty/Coil-build. TCRs should not be adjusted to a Mod. It is a spec of the wire just like the wire gauge is. Wire specs do not change just because you use a different Mod/Atty.
  
• You mentioned juice. That leads to the topic of gunked coils. As your coils get dirty, that dirt forms an thermal insulation around the wire. The Mod is still controlling to the resistance properly but the temperature delivered to the saturated wick starts to decline. This results in the perception of a weak hit. This phenomena is only exacerbated by exotic coil geometries like Clapton etc.

At the end of the day, find the best TCR you can. Ideally from the WIRE Manufacturer. The calculated ones on websites are good, but not great. I use Temco wire and they will send a MFG spec sheet upon request.

I use the same TCR (from the MFG) in all my Mods. The TCR represents the "WIRE" only, and that value doesnt change just because you put it in a different mod, or built a different geometry coil. Dial in your Mod to be as accurate as possible. Then tweak the temp setpoint if need be to get an identical vape perception.

Vaping is not a "set it and forget it" process. It does require tweaking if you are trying to get the same sensation every time. It is more complex than a lighter and a cig, but it is also magnitudes safer.

IMHO you are on the right track though. Temperature matters. Its worth getting it right!

 

[mikepetro]

BTW, I highly recommend sourcing your wire as close to the MFG as you can get, minimizing the middlemen.

Most of these vape branded wires are just some off the shelf product from a wire MFG that they respool and put a vape label on it, often with a lot of hype.

Because of the "House branding" they wont tell you the actual MFG so it makes it almost impossible to get the true MFG specs. You have to take the word of the "vape brand" and some are less trustworthy and/or knowledgeable than they will admit.

 

[MTL Connoisseur]

Mike Petro's Blog Index | E-Cigarette Forum

Start with this to see my methods.
Real Life temp measurements inside a 2016 era atty | E-Cigarette Forum

Then read these articles for more thought provocation:
VV & VW Mod Temperature Variables | E-Cigarette Forum

The basics of getting the most accuracy out of your TC Mod | E-Cigarette Forum

Then browse through some of my other blog posts for more info.

Thank you I will go through them soon!

@MTL Connoisseur – that is quite the post

Steam Engine Heat Flux is calculated as 1 watt/coil surface area. The math is correct, but the value is meant to be a guide and not taken as gospel. It is impossible for Steam or any other calculator to factor in the many variables on how e-juice and air flow influence the heat of the coil.

Thank you for explaining the heat flux value, I always thought it was the heat temperature,
how can this value be translated into Fahrenheit?

 

[MTL Connoisseur]

I did my studies about a year before the Yong Wu study on PLOS. The difference in my studies was that I actually vaped the test samples under real world conditions (while measuring) and could therefor give subjective observations in addition to the accurate instrumentation.

Wow such a great explanation, I will try my best to source those probes you linked and
test my setups with a fan blowing at the atty lightly, I am not trying to be exact spot on but rather a better method to the dry cotton test and or a little more accurate. If I set
my mod to 200f if I am at 190-210f I will be happy at least I know I am in the safe range.
I will go through your threads but I just wanted to raise my specific finding with my mod.

What's your take on my set temperature of 200f am I too low for MTL vape?
also what do you think about my TCR values of 141-151 are they abnormally high?

finally what brand wire do you recommend, steam engine TCR value of 88 seems to suggest
some type of pure stainless steel that has no other metals, that's unrealistic in real life
as you mentioned?
(Found you recommended Temco)

Thank you all gents this is educational and I am enjoying it!

 

[MTL Connoisseur]

OK, now lets look at doing your own measurements. IMHO your choice of thermocouples will give you an undesirable lag in measurement. You will hit a peak temperature in the Mod before the thermocouple has a chance to register it. The metal sheath on the first one will be next to impossible to get inside an atty and still vape. If you arent replicating the airflow through the closed chamber of your atty then your results will be useless in comparison to real life. You will get the fastest response from very fine diameter thermocouples. I like these in a 30AWG diameter. Also, I never had much luck with the SS braid jackets, they increase the diameter (3mm is huge in this application) making it hard to get the probe/wire in an atty and still be able to button the atty up. I landed on Kapton insulated probes as they are very fine and easy to snake into an atty. They limit you to 500F but you dont want to vape at/above that temp anyway.

The reason I got the 3mm diameter probe is to wrap a 3mm wire on it to test the ballpark
of dry temperature. It is not an accurate way but at least I will know the mods are behaving
sort of way.
your probe is perfect for wet-through wick test though as it will be as close as possible
to real life situation with a light breeze on the coil. I am guessing a closed chimney
will raise the temperature quickly and cool slower and if you factor in the airflow from the
attey and how pointy and precise it is on the coil giving a quick cooling effect.
Then the method above for wet-through wick and a light breeze and an open setup will get very close to that environment with the chimney closed.
Notice I said close but not perfect!

 

[Punk In Drublic]

I do not know of any way to translate HF into a temperature value. As mentioned there are other variables involved to which Steam can not account for. A vaping coil operates in a very unique environment.

Your temperature is too low which will explain why you could not obtain a satisfying vape. And your TCR value for SS316L is well beyond reasonable IMO.

SS316L is an alloy that allows a slight variance in the amount of materials used to make up the metal. This variance does influence it’s true TCR value. I have seen TCR values from metallurgist for SS316L that range between 0.00087 and 0.001. 0.00141 to 151 is, in my opinion too high.

Steam uses a fixed TCR value, just as they use a fixed value for all their other parameters. It would be an impossible task to develop a calculator that would account for the many, MANY different variances. AND, how does a user choose which one is correct or not. So Steams TCR value is not incorrect, it’s just not the same as what you maybe using.

 

[Punk In Drublic]

Then the method above for wet-through wick and a light breeze and an open setup will get very close to that environment with the chimney closed.
Notice I said close but not perfect!

Do not agree with that. To determine any kind of accuracy you need to set a benchmark of how the coil performs when drawing air across it as you would while taking a draw. Air flow while taking a draw could be very directed toward the coil thus influencing its temperature much differently than some diffused method such as a light breeze on an open deck.

Below is an example of drawing air over the coil vs blowing down the chimney. Green is power in watts, and purple is the coils resistance. 0.625 ohms is the coil at room temperature. I do not know the true TCR value of this metal, but it’s rise in resistance clearly shows how different airflow effects the temperature.

Lets assume the coils TCR value is 0.001, this would equate to a 13°C (55°F) difference between the 2. And if the coils true TCR value was 0.00088, the difference now equates to 15°C (59°F)

 

[mikepetro]

The reason I got the 3mm diameter probe is to wrap a 3mm wire on it to test the ballpark
of dry temperature. It is not an accurate way but at least I will know the mods are behaving
sort of way.
your probe is perfect for wet-through wick test though as it will be as close as possible
to real life situation with a light breeze on the coil. I am guessing a closed chimney
will raise the temperature quickly and cool slower and if you factor in the airflow from the
attey and how pointy and precise it is on the coil giving a quick cooling effect.
Then the method above for wet-through wick and a light breeze and an open setup will get very close to that environment with the chimney closed.
Notice I said close but not perfect!

If you try to wrap a 3mm coil around that SS Braided probe you will short your coil out thus invalidating any attempts. It will not work. Metal braiding along the length of the coil will result in damn near zero ohms.

Sorry, you are not going to like to hear this, but blowing a fan across the coil will not approximate the high velocity airflow going through the closed atty chamber. Do not underestimate the influence of airflow on all of this. Your thermal signature will not resemble actual vaping at all. We have discredited many a study because of this very point. It just isnt the same. The average MTL puff is about 50ml in volume, you are drawing that 50ml through a thimble size space in about 4 seconds. Not to mention the effects of directional turbulence etc inside the chamber. An open chamber cannot accurately replicate that.

What you can do with an open coil is verify the temp control of the Mod somewhat. If you set the Mod at 400, does your probe read 400 +/- 50 degrees, then try 300, 350, etc. It can validate (magnitudes better than cotton) if your Mod is attempting to control temp, but it wont validate the Mods precision. It WILL NOT simulate vaping, but it will only tell you if the temp control is in the ballpark.

 

[TrollDragon]

Wow, that's a lot of work to try and "perfect" a TC vape... Power to you though.

The first thing I would do is get away from the Stainless Steel wire which can vary in composition from manufacture to manufacturer and even batch to batch. You might consider going with Titanium Grade 1 as that would eliminate the whole TCR value problem.

Non DNA devices might have a better chance to give you a somewhat accurate TC vape with the Ti wire, but it's hit and miss on those devices.

 

[mikepetro]

Wow such a great explanation, I will try my best to source those probes you linked and
test my setups with a fan blowing at the atty lightly, I am not trying to be exact spot on but rather a better method to the dry cotton test and or a little more accurate. If I set
my mod to 200f if I am at 190-210f I will be happy at least I know I am in the safe range.
I will go through your threads but I just wanted to raise my specific finding with my mod.

What's your take on my set temperature of 200f am I too low for MTL vape?
also what do you think about my TCR values of 141-151 are they abnormally high?

finally what brand wire do you recommend, steam engine TCR value of 88 seems to suggest
some type of pure stainless steel that has no other metals, that's unrealistic in real life
as you mentioned?

Thank you all gents this is educational and I am enjoying it!

I vape MTL, and I am generally in the neighborhood of 420f. At 200f the Mod doesnt generate any vapor at all. 200f is below the boiling point of ejuice, you wont get vapor. See Juice Boiling Point and Vaping Temperatures | E-Cigarette Forum

As for the TCR values, I am not a metallurgist, I cannot begin to say if they are accurate or not. I vape using TI which is different that SS. Different alloys have different TCRs. Only the MFG can tell you for sure what the TCR is. Also, I tend to use TFRs rather than TCRs. TCRs are in and of themselves less accurate than TFRs, that is because a TCR is a single value but the temp/resistance relationship is not exactly linear, therefor TFRs are more accurate. Nickel has the widest TFR so I do know that it is the easiest metal for TC Mods to control. Narrow TFRs are more difficult to control as the resistance change per degree is a lot smaller. DNA Mods allow you to import a TFR.

I do admit to being a bit confused. In your opening post you stated "I will not put up with incorrect temperatures", but you are attempting validation methods that are very imprecise.

I like "Temco" wire, and I like Titanium. Temco is a wire company, not a vape company. So they only deal in specs, not hype.

Titanium TFR

SS430 TFR

Nickel 200

This shows you that TI is easier to control than SS430, and NI is the easiest of them all.

 

[MTL Connoisseur]

I vape MTL, and I am generally in the neighborhood of 420f. At 200f the Mod doesnt generate any vapor at all.

I do admit to being a bit confused. In your opening post you stated "I will not put up with incorrect temperatures", but you are attempting validation methods that are very imprecise.

I like "Temco" wire, and I like Titanium. Temco is a wire company, not a vape company. So they only deal in specs, not hype.

This shows you that TI is easier to control than SS430, and NI is the easiest of them all.

Thank you for the feedback and your help in educating me on the topic mikepetro and Punk In Drublic.

What I mean by putting up with inaccurate temperature control is in reference to the alternative mods to DNA and I only have a need for DNA 75c, I got no business in dealing
with DNA 250c and two batteries. 250c's are heavy bulky and not easy to carry around and I am not a cloud chaser or DL user.

So I am left with second hand Mods that I have to try to get as accurate as possible by dialing in TCR values, and most of those Mods because they are cheap do not have TFR to set.
So this is forced upon me to do with those cheaper mods ($50-$150) range, I looked into Dicodes and like the Danni tube that accepts 20700-21700 battery but just like ProVari's
before it is easy to knock down and I like my Kayfun's too much

Until someone realize there is a real good market for DNA 75c and creates single battery
setup for MTL "people like me", you are going to have to deal with this second hand market
of cheaper Mods and have to make them as accurate as possible.

 

[MTL Connoisseur]

I vape MTL, and I am generally in the neighborhood of 420f. At 200f the Mod doesnt generate any vapor at all. 200f is below the boiling point of ejuice, you wont get vapor. See Juice Boiling Point and Vaping Temperatures | E-Cigarette Forum

After this discussion I have changed my TCR based on both of you gents recommendations.

Knowledgeable person like who puts this type of effort in helping the community I am
comfortable doing this, I was not comfortable with the 3 line paragraphs posts suggesting
dry cotton test and set and forget it type of deal.

My current TCR is back to stock @109 and temperature feels nice at 300F-330F.

mikepetro I have read all of the threads and studies you suggested, really informative and have advanced my knowledge greatly on the subject!

I also have canceled my order for the SS braided probe's and ordered
these instead: https://www.amazon.com/gp/product/B00NG20OVO/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 

[MTL Connoisseur]

Wow, that's a lot of work to try and "perfect" a TC vape... Power to you though.

The first thing I would do is get away from the Stainless Steel wire which can vary in composition from manufacture to manufacturer and even batch to batch. You might consider going with Titanium Grade 1 as that would eliminate the whole TCR value problem.

Non DNA devices might have a better chance to give you a somewhat accurate TC vape with the Ti wire, but it's hit and miss on those devices.

Thank you for your kindness I know that SS is inherently not the best for TC but I feel safer
with SS than any other metal for some reason. I will look and educate myself more on
Titanium Grade 1.

 

[Punk In Drublic]

The 75C is not really a chip I am interested in, but Rebel mods makes 75C based mods. JAC Vapour makes a DNA 75 based mod which is quite popular, but is limited to an 18650 cell. You’ll find many higher end companies use the 75C chip, like Vicious Ant if you are willing to pay the price of admission.

I know you said you do not want a 250C, but sometimes you have to weigh your options. The Lost Vape Paranormal is not that much bigger than many single 21700 devices just as an example. But what you lose in size, you gain in efficiency and perhaps even longer run time. Just throwing that out there!!

 

[DaveP]

I have several DNA mods and a dozen or more non-DNA mods with TC functions. I've never really had a problem with performance and all I do is wind a 2mm SS316L coil and stretch it slightly to put air space between the coils before mounting. TC coils can never touch each other or the TC algorithm will try to operate on invalid readings from the coil. I can vape equally well at 10W in wattage or TC mode with a spaced coil.

Vaping is an art that's highly variable depending on the modes you use and the mods you vape. TC mode for me works fine, but I usually end up reverting at some point back to power mode. Not all TC mods use a proven algorithm.

 

[Punk In Drublic]

TC coils can never touch each other or the TC algorithm will try to operate on invalid readings from the coil.

Never had an issue with non-spaced coils and TC. The above picture I posted was a SS316L fused Clapton, the device read the rise in resistance as it should.