The basics of getting the most accuracy out of your TC Mod

First read this article from vaping360.com, which is a very good article to read ENTIRELY!

The TC mods I use are calibrated, and validated, with NIST traceable instruments to be +/- 10 degrees, but just because mine are accurate doesnt mean they all are.

There are a lot factors that must come together to have an accurate TC reading on a mod. A mere couple hundredths of an ohm can make a big difference with some of the wire being used.

• The manufacturer of the board
  • Top tier, I have long had confidence in the Evolv DNA line (made in the USA), but there are other good boards like Yihi, FSK, Dicodes, etc
  • 2nd tier boards generally wont be as accurate, and wont have as many options to tweak. Generally, if the mod is $50 or less it is probably a 2nd tier board inside.
  • Even 2nd tier boards can often be improved by running the Arctic Fox software and Firmware, which adds functionality very similar to Evolv's Escribe software.
• How well the mod was constructed, specifically with respect to the solder joints to the 510 connector, and the solder joints to "ground".
  • A cold or poor solder joint can increase resistance which will throw your measured temp off.
• Is it a quality 510 connector, many spring loaded connectors dont have enough tension.
  • The amount of force between the 510 center pin and the atty center is important. If there is not a a tight contact then it could introduce resistance which would throw you measured temp off. This is most commonly an issue on economy mods.
  • The Cisco 510 V2 or the Evolv 510 are good examples of a high quality 510.
• Was the mod calibrated to account for internal resistance.
  • Better boards will allow you to plug in an "offset" resistance to compensate for the accumulated resistance of the the 510 and internal solder joints.
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• The quality of the atty, specifically its internal resistance and stability under heat flux.
  • Some attys are just not good for TC use. Certain attys, particularly if they have lots of parts in the center conductor path, will add, or even worse - change, resistance as the atty heats up. You want an atty that maintains very stable resistance.
• The accuracy of the TCR or TFR curve being used with respect to the wire.
  • The vast majority of TC mods (FSK being the exception) rely on "knowing" what resistance to expect at a certain temperature. This is usually provided by the manufacturer of the wire.
    
  • This relationship is expressed as either TCR or a TFR.
    
  • A TCR (Temperature Coefficient of Resistance) which is a single number that the TC Mod will use in its algorithms to calculate the temperature.
  • A TFR (Temperature Factors of Resistance) which is a series of numbers representing a curve of numbers that the TC Mod will use in its algorithms to calculate the temperature. IMHO the TFR is the more accurate of the two methods since the relationship is usually not linear.
    
    
    
  • If you are building your own coils, or just trying to find the TCR/TFR for a certain metal, Steam Engine is a great place to go. It has all the canned calculators you are likely to ever need.
• The quality and consistency of the wire.
  • Different manufacturers of wire are more consistent than others. If the gauge (diameter) of wire changes at all throughout the spool it could cause hot/cold spots, if the alloy changes throughout the spool it will change resistance on you vs what the TCR is expecting.
  • I like Temco wire but there are many others available. Avoid unknown brands, or brands that dont state the specific alloy of the metal.
• The technique of the user in assembling all of the above.
  • Good tight connects, no shorts anywhere, no corrosion or dirt on any of the connections, etc are important in making sure the resistance of the mod is accurate.
  • "E-juice does not conduct electricity very well, but like everything else, it does conduct a little. Burnt juice leads to carbon buildup on the coil, and carbon conducts electricity fairly well." Therefor burnt coils can throw off you measured temp easily. Keep your coils clean.
• The bottom line is that ANYTHING that might increase the resistance in your mod/atty/coil will cause your temperature reading to be inaccurate.

Some tips for TC newbies.

• Start with SS316 or SS430 wire. Both of these can be used in either TC mode or wattage as you learn the ropes.
• Most TC mods will allow you to set a maximum wattage, set this wattage to be about 25% higher than the wattage you usually vape at. This is only necessary in the beginning as you learn TC. Once you have learned it, and are comfortable with your Mod being accurate, then you can just max out your wattage, as the TC (technically temperature "limiting") will automatically limit the wattage to keep you from going over-temp.
• If you find that you normally vape at 420f but all of a sudden have to crank up the temp to get a satisfying vape, check for crud on your coil.
• If you find that you normally vape at 420f but all of a sudden have to lower the temp to to keep from getting a burnt tasting vape, check for hot legs on your coil.
• Dont take a "hot" atty off of another mod and then put it on a TC mod, the results will not be good. A TC mod measures (what it assumes is) the "cold resistance" the first time you attach it to use as a baseline. If you attach a HOT atty your baseline will be off and your temperature readings will not be accurate.

©2017 Mike Petro. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.