Temp Control Q & A

Discussion in 'Temperature Control' started by KingPin!, Jul 19, 2017.

  1. KingPin!

    KingPin! Well-Known Member

    Jul 19, 2017
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    Hi All
    Thought it would be good to have a dedicated thread for temp control Q & A for newbies and veterans alike to help answer those temp control dark arts questions

    When I got into building my own coils one of the things I've noticed is how easy it is to get a dry or burnt hit especially when you put in some of those bigger coil builds. Now I know some will say that's a wicking issue or try turning down the wattage.... whilst that is true, in a lot of cases these chunky heaps of coiled madness just can't cool down quick enough!

    so I started looking into temp control as a means to maintain the flavour...draw for long periods of time...chain vape like a madman...avoid cremating my cotton...and not mash up my coil that I spent bloody ages building!

    What I've learnt so far

    There are 4 main things to remember for temp control

    1) All metals change resistance when heated, but it's those metals that change more that are the best suited for temp control, and its for this reason most temp control mods have Nickel, Titanium, and Stainless Steel as a default ...imagine a hose pipe fully open, now pinch it (resistence in our case), it's harder for the water (current in our case) to get through... that's exactly what's going on here as the metal is heated.
    You will start with a new coil build at say 0.3ohm at room temperature and when heated it goes up to 0.5ohm ...the resistance goes up (some metals change far more than others) this effect is known as Temperature Coefficient of Resistance (TCR*) It's the average amount the resistance changes for every 1 degree Celsius heated

    (*note there is a proper temperature curve some devices can utilise which is different to the average linear line that is TCR but for ease of explaination I'll stick to TCR)

    note 2, Kanthal is usually out of the question for temp control on most mods as its resistance changes so little when heated although the hohmwrecker G2 supports it

    2) The type of Metal you choose for your coil changes the correct TCR you use on your mod (I believe I've read somewhere you also need to factor in your own mods internal resistance although on most regulated devices I would assume the chip accounts for this?)
    I'll post a follow up after this of all the metals common TCRs

    3) Temperature - this is what you want your mod to max out at and stay at when it gets there ...meeting all of those things I listed above (avoid cremating cotton etc)... now it's important to note your mod isnt actually detecting the temperature, it's carrying out calculations 1000's times a second based on reading the starting ohm resistance and the resistance while heating this is why TCR is important..(it's also really important you have a good connection on your deck for your coils as well, dodgy ohm readings to start with are bad news, health and safety first people)

    • A coil is at 0.10Ω at room temperature (20°C / 68°F)
      • You vape and the chip sees its resistance is now 0.22Ω
        • So it knows its resistance rose by 0.12Ω
      • Then it calculates using the TCR you pre set of 0.006 (NI200) thats a resistance rise of 0.12Ω equals a temperature rise of 200°C (392° F)
        • And therefore the coil temperature is now 220°C (428°F)
        • (0.22Ω - 0.10Ω) / (0.006 * 0.1Ω) = 200°C (392°F)
        • + 20°C (68°F) [starting temp] = 220°C (428°F) [coil temp]
    4) Wattage - This is serving to only get you to the temperature you set earlier because your mod will maintain temperature when it's peaked (that's why you see that temp message on your mod) it's pulsing here to maintain temp rather than keeping going in power mode, it's not turning off like a lot of people think ....
    So set this based on how quickly you want to reach your max temp, if like me your not fussed on the pulsing bit set it lower, if you want it at max level immediately raise it there is no right or wrong

    No doubt there are things I've forgotten or don't yet know so Q&A time guys

    Edit: after creating this thread I found a really useful article which has a very thourough explanation of all the elements affecting TC well worth a read

    Moderator and rocketyos like this.
  2. KingPin!

    KingPin! Well-Known Member

    Jul 19, 2017
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    Every type of wire has different Temperature Coefficient or TCR and here is the list of the most common and uncommon wires used to vape:

    I will admit that I am stealing this off an article but it has a lot of TCR values. It shows how little we really know about TCR of wires since some of them have multiple values.

    Edit: added kanthal A1
    Kanthal A1 [0.000002] (steam engine - notice how low this is and why most mods can't support this... the chip has to be very sensitive!)

    Nickel DH: [0.007036]

    Ni80 [0.000112] (according the steam engine.org)

    Ni200: [0.00600] (According to Steam-Engine.org)
    Ni200: [0.00620] (According to @DJLsbVapes and other various sources)

    Nifethal 70 (Alloy120): [0.00525]

    NiFe30 (StealthVape): [0.00500]

    Tungsten: [0.00450]

    Nifethal 52 (Alloy52): [0.004036]

    NiFe (Reactor Wire): [0.00400]

    TitaniumGrade1: [0.00366] (According to Steam-Engine.org)
    TitaniumGrade1: [0.00350] (According to the SX Mini Manual, @DJLsbVapes and other various sources)

    TitaniumGrade2: [0.003525]

    NiFe30 (Resistherm): [0.00320]

    SS410: [0.00155]

    SS430: [0.00138]

    Invar 36 / Nilo 36 / Pernifer 36: [0.001116]

    SS304: [0.001016] (According to Steam-Engine)
    SS304: [0.00105] (According to @DJLsbVapes and other various sources)

    SS316L: [0.000879] (According to Steam-Engine)
    SS316L: [0.00092] (According to @DJLsbVapes and other various sources)

    SS316: [0.00088] (According to Steam-Engine.org)
    SS316: [0.000915] (According to @DJLsbVapes and other various sources)

    SS317L: [0.00094] (According to Steam-Engine.org)
    SS317L: [0.00088] (According to @DJLsbVapes and other various sources)

    SS317: [0.000875] (According to @DJLsbVapes)

    Not all wires we buy are of the best quality, some may contain impurities but this is the generally accepted TCR list for the common materials
  3. Phil_Lee

    Phil_Lee Active Member

    Aug 12, 2017
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    I can add that at least according to Phil Busardo and DJLsbVapes most mods do NOT have the internal resistance set or the amount by which this changes as the case warms and cools (case analyser in EScribe). Even on DNA devices which support the setting of the correct values. I do wonder to what extent this may lie behind the relatively poor temperature control performance of other chipsets.
    My DNA did (VapeDroid C1D2) but I managed to mess it up playing in EScribe and had to run it again, so may have slightly more accurate results for my individual example, rather than having values set from a sample of 'Droids - which may even have been pre-production and therefore differing slightly from those that came off the production line.
    I'd encourage anyone to run the case analyser and set the internal resistance.
    The first is easy - just follow the steps in EScribe. For setting the internal resistance you have to put a dead short (0.000Ω or as close to it as you can get) on the 510. The best tool I know of for this that is readily available is the Vandy Vape polishing rig, intended to hold tube mechs and atomisers in a drill for fast and easy polishing, but it is solid stainless steel with (of course) both female (for the atty) and male (for the tube mod) 510 threads. Screw that into your 510 and measure away! I get 0.007Ω on mine.
    Finally, not all TC pulses - DNAs don't, they continuously adjust power in small increments. Others, from Phil Busardo's graphs, use pulse width modulation, where a pulse is sent at the set wattage whenever the chipset detects the resistance (and therefore, temperature) is too low - the duration of the pulse is decided by the amount by which the resistance (temperature) falls short of what has been set. The better ones (Like Dicodes or Yihi) do this very fast and frequently, but the cheaper you go, the slower the response!
    Last edited: Aug 13, 2017
  4. aeon

    aeon Member

    Aug 10, 2017
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    I TC'd from the very beginning because my first mod was a TC device (Triade) and I wound my own coils in SS from day one.

    I've gotten a dry hit before, but it was always because I absentmindedly allowed a RDA to go dry, or because I forgot to burp a RTA.

    People have often talked about gunked-up coils, and cleaning coils. I never have gunked-up coils...and I'm not sure if that is because of the juice I use, or because I keep the temperature on the short leash, or both.

    In general, I want to hit my builds with power in the range of 75-125 watts...but I allow my mod to do what it likes as long as the temp is held in check.

    I fired up at work with the coils exposed and used a quality thermal imager to take readings. I was impressed by how accurate and controlled the TC was.

    I tend to like a temperature-neutral vape...neither warm nor cool.

  5. KingPin!

    KingPin! Well-Known Member

    Jul 19, 2017
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    Thanks Phil :) I didnt know about the internal resistence not being set that's good to know
    Phil_Lee likes this.
  6. DevAuto

    DevAuto Well-Known Member

    Sep 26, 2017
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    I'm vaping on a 5 wrap, 26 gauge, 316l SS coil, at 420 degrees, and I do get gunked up coils. The time it takes to gunk up varies from Juice to juice, it seems the thicker and sweeter the juice, the quicker it gunks up. I have one juice that gunks up every 3-4 weeks and another that takes almost 2 months before it happens. When it does, I pull out the cotton, dry burn it clean, rewick with fresh cotton, and I'm good until it happens again.
    Phil_Lee likes this.

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