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TC beyond Ni200: Nickel Purity, Dicodes; Ti, SS, Resistherm NiFe30; Coefficient of Resistance

Discussion in 'Temperature Control' started by TheBloke, May 28, 2015.

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  1. Madnapali

    Madnapali Super Member Verified Member ECF Veteran

    Jul 16, 2009
    Northeast Ohio, USA
    It was pretty clear to me from the get-go it's a money grab. China edged into their territory, took A LOT of it, and this is their ill-advise cavalry charge to get it back.
     
  2. druckle

    druckle Ultra Member Verified Member ECF Veteran

    I'm one of the lucky "500" and I'm trying to decide whether the first one should be an SX J or an Ares. Dunno...since I'm pretty sure one Whiteout won't be enough for a tinkerer like me.

    Duane
     
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  3. TheBloke

    TheBloke Ultra Member Verified Member

    Mar 30, 2015
    Brighton, UK
    SXK NP setting for a 0.41Ω coil read as 0.35Ω using Zivipf Titanium Grade 1 (TCR 0.0035): recommended NP40


    [​IMG]

    NP 35 is the 'right' setting according to the TCR; NP 40 is the most accurate setting. So the resistance drop appears to require a slight increase, but nowhere near what my calculator indicated.

    Putting these numbers into the calc gives a recommendation of NP 51! Clearly that is way, way off.

    As to why, I cannot yet say. Most likely conclusion is that it's using a different resistance figure for the TC calcs than the one it shows on screen. Maybe the "low resistance" is really mostly a display problem? Hard to know as yet. I will try and do some testing on the output volts of the device to see if I can conclude anything further from that.

    @druckle - this doesn't mean your NP 45 is 'wrong'; your Titanium might not have the same TCR. Plus it may well vary according to the real resistance / read resistance of a given build.

    What we can see immediately is that SXK's TC is rather less accurate overall - jumps a lot both above and below, so the target is more a 'trend' than a limitation. Though this is still a dry coil situation, a test where it's reasonable that it doesn't do super well (even if its more expensive competitors do better.) A wet coil temp test will be more interesting.

    EDIT: Added NP 41 for comparison
     
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  4. tchavei

    tchavei Vaping Master Verified Member ECF Veteran

    Jul 15, 2014
    Portugal
    Really? How odd. Mercedes stated the w204 model had been tested for 120.000 miles from the desert to the coldest regions in northern Europe.

    Yet they had the Delphi injector disaster.

    Basically what I'm trying to say is that long term testing doesn't warranty a flawless product BUT what's the secrecy about how long a testing program has been going on unless it's something 'shameful' enough to hide?

    Regards
    Tony

    Sent from my keyboard through my phone or something like that.
     
  5. TheBloke

    TheBloke Ultra Member Verified Member

    Mar 30, 2015
    Brighton, UK
    Added NP41 to my SXK graph. I suppose it could be a matter of viewpoint whether 40 or 41 is better - they are inaccurate in different ways. NP40 goes low more often than 41, but 41 goes too high more often.

    I'd most likely choose 40 based on this data alone.
     
  6. druckle

    druckle Ultra Member Verified Member ECF Veteran

    Cool.....Thanks for that info.

    I'll experiement with 40 and see what the vape experience is like and then do some water tests again to see what that tells me. I haven't experienced any burned rayon but I don't know for sure what the char temp is for the rayon I have and I haven't done a direct pole to pole copper test to find out what the Magma clone resistance is.

    So far the SXJ is giving me a satisfying vape and I sure can't complain about the price.

    Duane
     
  7. druckle

    druckle Ultra Member Verified Member ECF Veteran

    Agreed...long term doesn't guarantee anything...but IMO short increases the odds of a fubar outcome.

    Duane
     
  8. druckle

    druckle Ultra Member Verified Member ECF Veteran

    You know...looking at that SXK curve...the accuracy is better than I expected to see.
    I wish we had grade 1 titanium wire with the full range of specification values. But, on the other hand my gut tells me that the errors for titanium are going to be inherently small because the primary contaminant is oxygen and not metallic alloying additions.

    Anyway....no water test yet...because I'm keeping my feet up and enjoying sucking on a Magma with my favorite juice and an SXK set with the 40 "purity value".

    This isn't yet the time to suck it dry or take a water test break.

    Duane
     
    • Like Like x 1
  9. TheBloke

    TheBloke Ultra Member Verified Member

    Mar 30, 2015
    Brighton, UK
    To be fair for tweakers/enthusiasts, the PC interface looks really interesting. What I'm not sure of is what it's meant to have for Joe Public. They can't use non-Ni200 without the PC software, which 10-15% of them can't even use (Mac) and another 50+% probably won't ever want to use ('CSV files? What the hell is that?'). 200W sounds bizarre, especially for TC. Lipo could be cool, but most of the reason that's there seems to be to enable the 200W.

    So yeah, for users who don't fall into the group who will rabidly play with the PC side, I have to agree that it doesn't seem to offer a huge amount in this release.

    But I hope that they will add the missing features - most particularly on-mod TCR adjustment - ASAP, which they can at least do now it has FW updates.

    I'm pretty sure we'll see a DNA 70/80/whatever announced before too long which will support normal batteries (1x18650 in particular). I really can't see how 200W is going going to be necessary to 99% of people. I'm willing to give them the benefit of the doubt on it possibly being useful for TC, if they have a good algorithm in there - eg it knows to apply 200W for only microseconds to bring it instantly to temp. But it really will be microseconds, so I can't yet quite understand why it's so beneficial to have 200W for 0.1 second versus 100W or even 50W for proportionally longer - can one really tell the difference?

    Anyway, we'll see soon enough!
     
    • Like Like x 1
  10. Madnapali

    Madnapali Super Member Verified Member ECF Veteran

    Jul 16, 2009
    Northeast Ohio, USA
    I haven't actually looked into the PC feature yet, mostly because I'm not interested in the product... heh. From how you put it, sounds nifty yet unnecessary and perhaps a bit hamfisted for a layman. I'm an engineer so I'd be OK but we can't say that about the guys who blow up batteries and what-have-you.

    TCR adjustment is a must-have now that we know about it, especially if it's made easy and the info needed to execute it is handy. Not like having to search through this thread or ask you, haha, but in the user manual.

    For that very last bit, I don't think anyone can tell the difference. My DNA40 wouldn't even use the full 40w for the preheat. I'm currently using a HeatVape Invader Mini which I'm pretty sure has no preheat, and I don't see a difference on that compared to DNA40 at all. Also... If you push 200w into a 28g or 30g nickel coil, even for a microsecond, it could very well blow the positive leg. I had the bright idea to try my Veritas on 40w, with temp control on, and it blew nearly as soon as I hit the button.
     
    • Like Like x 1
  11. dr g

    dr g Moved On ECF Veteran

    Mar 12, 2012
    Paradise
  12. funkyrudi

    funkyrudi Senior Member ECF Veteran

    Apr 6, 2014
    Cologne
    @TheBloke
    Would you be so kind and show the graph for your tested Ni200 wire on the Dicode. Actually I´m a bit astonished about the far too low TCR. I got all my wire from Zivipf and there is nothing to complain about the Ni200 wire. Set at 420F, it always does what it should.
     
  13. vapealone

    vapealone Senior Member

    Jun 16, 2015
    Don't you worry I am already panicking :) because of a different reason tho.
    It just I got a Deja Moo.
    Evolv is promising something to bring into vaping and because the so called game changer and revolutionary things (e.g. Dc/DC conversion, power regulation, RDT) are already proved technologies it is too easy to believe that they can do it.
    And yes, it is quite funny that in 2015 there is no way to interact with any of the top of the range boxes in a sensible way. (Puff counter and log doesn't count):)

    Anyway, for the sake of the endangered clueless tinkerers I will publish here my Ultimate TCR Curving Guide :))) Just give me a few hours
     
  14. vapealone

    vapealone Senior Member

    Jun 16, 2015
    The Hitchhiker's Revolutionary* Manufacturer's Guide to the Galaxy Temperature Dependent Resistance Curves
    * and Game Changer and Prodigious and Visionary . Very.

    [​IMG]
    STEP 1: Don't Panic!
    • You can’t go wrong. You don’t have to be either overly precise or deadly accurate. Resistance based temperature measurement relies on empiric parameters. Hence, any precise RTDs should be built and calibrated to the very task and circumstances. But vaping is too diverse for proper calibration so you can blame the particular build, atomizer, weather condition altitude whatever if something goes amiss.
    • Besides, there is no living form who can calculate the boiling point of any pure material let alone solutions. And the boiling temperature of the e-liquid itself is an even bigger mystery regardless of the available empirical data about the boiling temperatures of some main ingredients Another perfect scapegoat.
    [​IMG]

    • Your only enemies are those disrespectful .......s, a.k.a. advanced vapers, who dare to use different sensors and probes to test your masterpiece then trolling around with their imaginary result. Damn them!
    • Luckily, you don’t even need to calculate any TCR at all to protect yourself against those trolls, however this Guide will cover that too. A simple temperature factor will do the job just fine. As long as you can allocate a certain resistance factor to each of the available temp presets you are safe. It means 41 factors to cover all the steps from 100C to 300C.
    • Now, we got a problem. We don’t have 41 factors.It could be quite straightforward to do some experiment yourself or to get some accredited results from a respectable laboratory and do the coding on it but hey, money doesn’t grow on trees. Why should waste any at all? Lets google some basic data to start with and we are good to go.
     
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  15. tchavei

    tchavei Vaping Master Verified Member ECF Veteran

    Jul 15, 2014
    Portugal
    I guess this explains why your nick is "vapealone"... :p
     
    • Like Like x 5
  16. TheBloke

    TheBloke Ultra Member Verified Member

    Mar 30, 2015
    Brighton, UK
    Err, thanks for that @vapealone :) I think you are directing this at Evolv for not pre-publishing curve data for any wires besides Ni200? In which case yes I do agree it's poor show of them not to provide even a basic data set for wires other than Ni200, and doubly so to even require the curve system when allowing entry of a simple TCR figure is more than adequate and would be immediately usable for far more users.
     
    • Like Like x 1
  17. vapealone

    vapealone Senior Member

    Jun 16, 2015
    The Hitchhiker's Revolutionary* Manufacturer's Guide to the Galaxy Temperature Dependent Resistance Curves
    * and Game Changer and Prodigious and Visionary . Very.


    STEP 2: Plotting a curve
    For illustration purpose we will use Ni200 as it’s TCR is definitely nonlinear. Titanium would be too easy.
    Specialmetalsdatasheet is perfect, so we just load the temperature and resistance values into a Google sheet. (SI for now, Imperial on demand)
    Now, we can derive our factors, relative to 20C (room temperature) and insert a chart to see how big the trouble is. (Resistance factor is divided by 10 for demonstration) So far, we can agree that Ni200’s resistance change is indeed far from linear even within the 20-300C vaping range.
    [​IMG]
    To do the magic we need to import(copy/paste) our input data into a highly sophisticated mathematical software called Geogebra which happens to be open source and available on several platforms. (we will import temperature and resistance data only)
    Then we create a polyline from the spreadsheet data and add two lines representing our temp limits and we get this:
    [​IMG]

    Then pick the points from our range with +1 from above and below and play a bit with the FitPoly command to find the polynomial which suits us.
    [​IMG]


    This quintic function looks pretty promising. (any polynomials of lower degree didn’t work to well).

    1.0358E-14 x^5-1.752E-11 x^4+7.0109E-9 x^3+3.8532E-8*x^2+0.00031974x+0.09037

    Of course, it is way off beyond our range, but we don't care.
    [​IMG]


    Our sole purpose is to gain an equation we can use to compute all the missing factors with acceptable accuracy . And this lusty curve will do this job. Ok, an inflection point around 300C would be even better but that’s what we can get for free.

    So we open a new tab in our sheet, copy the known values into it and includes the missing temperature steps. (known data: normal, calculated: italic)
    Now we derive the factors and we are actually ready. Even though we had no initial data for all the temp options now we can allocate a surprisingly accurate resistance value to all.

    [​IMG]

    TCR calculation (Column ‘D’) is just a bonus feature for those who happen to own a mod with TCR settings option.




    Thank you for reading

    Happy tinkering


    P.S.

    I have used this datasheet because of its immense data. However this particular Ni seems a bit lazier than others with smaller resistance changes and TCRs (e.g. its R300~=2.71*R20. I generally use Kanthal's Nickel DH as reference and it has 2.97*R20@300C)

    But like I said, values depend on the circumstances:) It is not my fault:)
     
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  18. TheBloke

    TheBloke Ultra Member Verified Member

    Mar 30, 2015
    Brighton, UK
    Ah ha, now that is interesting. Thanks @vapealone !

    I would love to play about more with this. The maths is a little beyond my experience (OK quite a lot!) but the results are very interesting.

    So actually what you are seeing from you datasheet is that the TCR of Ni200 around the target temp is 0.005! Not 0.006. So maybe the wire I measured @ 0.0045 - 0.005 is not so strange. But this stlill doesn't explain why the mods with pre-programmed Ni200 TC, like the IPV4 in particular (verified elsewhere as accurate, eg by Busardo) was going way over temp for me. So I do think my wire is unusual.

    Hopefully more will become clear when I get a second set of Ni200 to verify with.

    EDIT: sorry I see you did post the Google sheet, great thanks! Looking now.
     
  19. vapealone

    vapealone Senior Member

    Jun 16, 2015
    I think, there is difference between wire and wire, Standards allow some tolerance.
    More importantly, we are talking about average temperature. The legs are cooler(preferably) the very middle the hottest (again: preferably)
    Manufacturers quite likely tries to compensate for that somehow. E.g. picking one specific build (resistance, likely gauge, ID, wrap counts) and factoring the result accordingly. If your build is different than your result will be different too.
    But I have to add, that I don't care about temp setting (readout) at all. At least not in numerical way.
    I got a simply trick to set the value where it should be and as long as it is the 20-300C range, I am good.
    The fact that I don't know the exact coil temperature and my readout is way off doesn't bother me.
     
    • Like Like x 1
  20. tchavei

    tchavei Vaping Master Verified Member ECF Veteran

    Jul 15, 2014
    Portugal
    My brain just melted...

    Now can you repeat this for Ti, although you say it's simpler? I would love the the actual curve of Ti and then cross reference both curves in the same graph to make accurate readings between both curves (to establish what ni settings to use to vape Ti on unsupported boards like the dna 40.)

    Regards
    Tony

    Sent from my keyboard through my phone or something like that.
     
    • Like Like x 1
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