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

[vapealone]

I do understand your concerns absolutely. But at the same time, I am fairly confident that Evolv have implemented the curve - the reason I started doing these Titanium tests at all is because we found, anecdotally, that genuine dna 40 devices needed a different and higher temp setting for Titanium than Chinese devices such as the Yihi chips and the ChiDNA 40 clones. At first we thought that might be pre-heat, but my testing rules that out : it doesn't arbitrarily pre-heat an already heated coil, in fact it's pretty damn great at keeping a heated coil at a static temperature regardless of how many times you release and re-press the fire button. I was very impressed with that.

I'll do a dna 40 / Ni200 test next so we'll get the info as soon as possible.

just FYI you that in the meantime I opened a ticket and asked for confirmation from Evovl.
Brandon replied and confirmed that they use some dynamic TCR model.
Being paranoid this letter didn't reassure me fully mainly because of some pseudo-scientific buzzwords he used. Mildly arrogantly and definitely incorrectly But he replied, I appreciate it.

So I did a quick self check* and I am happy to report that I was wrong and Evolv is indeed using some dynamic/variable TCR.
And to my utter surprise the result agreed with my figures with 0.0000x precision. I mean I think my numbers are quite all right but my test wasn't overly professional And I got only a handful results between 185 and 250°C where the TCR curve is almost linear. Anyway, this is what I got

However according to this quick and nonprofessional test some accuracy issue is quite likely as there was some constant difference between the displayed and the measured (on the atty) voltage. Regardless whether it is some internal resistance issue or not it can easily yield an actual temp difference too. (Worst case scenario is up to 15°C higher displayed temperature)

*The test was pretty simple and didn't involve any temperature measurement as I was targeting their TCR.
I used a massive Alloy120 coil and air cooling and simply checked the voltage (on the mod and on the hard wired multi-meter) and temperature (on the mod) readouts when it reached equilibrium. Made 10+ go from 1 to 2W and calculated R(T) and TCR.

P.S.: My multimeter shows some 1.3mV constant voltage when the atty is on the mod. (0.000mV when not). Somethimes higher. Even when the the screen is off. Apparently it goes to zero when in sleep mode. Any thoughts?

 

[TheBloke]

Good stuff @vapealone. I started doing graphs for the DNA 40 with Ni200 last night and yeah it's pretty accurate as expected. I'll post soon, I had some other things come up first.

It sends a constant voltage for the heartbeat, I also see it in terms of coil temperature - always 2-3°C higher than background temp. It's constantly probing the coil to see if it needs to refine the resistance. But with a coil on and detected I see 0.34mV static. I did see 1.5mV with a coil on but not detected (ie I hadn't pressed fire yet to get it to read resistance) - I'm not entirely sure what that is, but I assume it's part of the same process.

 

[vapealone]

Good stuff @vapealone. I started doing graphs for the DNA 40 with Ni200 last night and yeah it's pretty accurate as expected. I'll post soon, I had some other things come up first.

It sends a constant voltage for the heartbeat, I also see it in terms of coil temperature - always 2-3°C higher than background temp. It's constantly probing the coil to see if it needs to refine the resistance. But with a coil on and detected I see 0.34mV static. I did see 1.5mV with a coil on but not detected (ie I hadn't pressed fire yet to get it to read resistance) - I'm not entirely sure what that is, but I assume it's part of the same process.

Awesome[emoji2]

Sent from my GT-I9505 using Tapatalk

 

[Madnapali]

Has anyone tried bulding a center-post Genesis like In'ax or NextGen with titanium wire? I've been vaping the crap out of my NextGen with nickel and got curious if it would even be possible with titanium, since the thinner wire might have too much resistance and the thicker wire might not even go through the nut.

 

[Arthur]

28ga should work no? If you can cram 7ish wraps in. Lol. I was thinking about doing ti on my In'ax later

 

[Madnapali]

28ga should work no? If you can cram 7ish wraps in. Lol. I was thinking about doing ti on my In'ax later

Let me know how that goes. I don't think anything fatter than 28g will fit in the NextGen.

 

[Arthur]

Let me know how that goes. I don't think anything fatter than 28g will fit in the NextGen.

You are correct sir. Dunno if I'm gonna do the in'ax our the kraken. I'll let you know

 

[TheotherSteveS]

Has anyone tried bulding a center-post Genesis like In'ax or NextGen with titanium wire? I've been vaping the crap out of my NextGen with nickel and got curious if it would even be possible with titanium, since the thinner wire might have too much resistance and the thicker wire might not even go through the nut.

twisted 32g??

 

[TheBloke]

Hey @vapealone

I've been thinking about doing the same as you and getting some Alloy 120 from Resistance Wire. My main concern is that it seems so much better than Resistherm - available in wide range of sizes; higher TCR (0.0043 - 45); generically available - so why did Dicodes not choose that instead of Resistherm?

It could be that they wanted to control the market with a rare wire. Or perhaps Resistherm has some major advantage?

Could you tell me:

1. Can you dry burn it and make micro-coils out of it, like Kanthal?
   1. With Resistherm, I can make a micro-coil and then dry burn it exactly like Kanthal - tweaking it until it glows perfectly inside-out, exactly like we've always done with Kanthal
2. What is the resistance per metre like? Maybe that's the difference - I think I just saw on a data sheet that the resistance might be as low as Ni200's?
   1. If you make a standard 8 or 10 wrap coil with say 26 or 24 gauge, what will the resistance come out to?
3. Any other factors you can think of to compare it against Ni200 or Kanthal?
   1. Is it as strong as Kanthal generally? As usable for coiling?
   2. Have you ever tried using it for non-TC vapes - I can do that with Resistherm; did it perform OK?
      1. Obviously with a higher TCR I'd expect, for a non-TC vape, the strength of the vape to decrease as the resistance increases. But does it at least seem to work in principle?

Thanks in advance!

 

[Madnapali]

twisted 32g??

Twisted 32g nickel is what I use in all my gennies. The resistance on the same in titanium may be too high for TC, though.

 

[TheotherSteveS]

Twisted 32g nickel is what I use in all my gennies. The resistance on the same in titanium may be too high for TC, though.

why too high??? how many wraps etc??

 

[TheBloke]

Twisted 32g nickel is what I use in all my gennies. The resistance on the same in titanium may be too high for TC, though.

Twisted 32G will be about 30G in terms of resistance, and 30G should be OK for Titanium. 8 wraps will be around 0.85Ω, which is getting up to the limit of most TC mods, but not over it - most mods I've seen specs for state 1.0Ω as the maximum. (The Dicodes is the exception, with no stated maximum besides the maximum of the mod in general, which is 3Ω I think.)

Of course it's quite likely few if any people have tested TC at the upper reaches of the resistance limit. But at least on paper it should work, and there's no technical reason why it shouldn't be just as accurate as normal - the calculation is identical.

A 0.85Ω Titanium coil heated from 20°C to 232°C will increase in resistance to 1.48Ω, which is well within the VW resistance range of any TC mod.

I'm assuming that when the mod/chip manufacturers say TC works up to 1.0Ω they mean the starting resistance, and the end resistance of the coil can be higher. Indeed that's probably why they state a maximum - an Ni200 1.0Ω coil (if such a thing could be built!) would rise in resistance at 300°C (the max TC temp on most mods) to 2.67Ω, which will be around the upper limit of the ohms range for most regulated mods.

So that makes sense they'd set 1.0Ω as a limit when thinking about Ni200 - it's not that TC can't work at any resistance range, it's that they limit the base resistance to be sure the increased resistance of the coil once heated won't exceed the maximum ohms of the mod.

 

[TheBloke]

Actually that's quite interesting. I just checked the DNA 40, and it lists a maximum TC resistance of 1.0Ω and a maximum VW of 2.0Ω.

We can assume (hope) the maximum for TC means the base resistance, and thus one could build a coil which is at, say, 0.9Ω at room temperature, and the mod will still handle it when its resistance rises under heating. But if one could build a Ni200 coil of 0.9Ω, and then set TC to 250°C - not even its maximum - the resistance of that coil would rise to around 2.1Ω. Which is over the stated maximum VW ohms!

So I wonder what happens then. And whether they've even considered or tested for that, given how practically impossible it would be to get a Ni200 coil at 0.9Ω With Titanium it's certainly possible, but the lower TCR means it's unlikely to ever exceed 2.0Ω.

Actually, for Titanium it works out perfectly A 1.0Ω Titanium coil heated to 300°C increases its resistance to 1.98Ω! Just within the limit. But heat it to 315°C and it's 2.03Ω.

And although the DNA 40 stops at 300°C (or 315°C if you set it to 600°F), because it doesn't technically support Titanium and the temp settings heat a Titanium coil to more than specified, you could actually heat a Titanium coil to 380°C or so.

So I now really want to know what happens if you put a 1.0Ω coil on a DNA 40 and set the temp to, say, 250°C - which as we know from my probing will actually reach around 320°C, and therefore 2.05Ω That will take the coil over the maximum ohms of the mod. Will it just not heat it fully? Will it crash?

But anyway, yeah - with Titanium, as long as you keep your coil to 1.0Ω or less - which allows use of up to 8 wraps of 30G and should be the same of 32G x 2 twisted - you shouldn't have any practical problems within the normal vaping temperature range. And ditto Ni200 simply because it's impossible to build a usable coil at anywhere near the maximum ohms.

 

[TheotherSteveS]

Actually that's quite interesting. I just checked the DNA 40, and it lists a maximum TC resistance of 1.0Ω and a maximum VW of 2.0Ω.

We can assume (hope) the maximum for TC means the base resistance, and thus one could build a coil which is at, say, 0.9Ω at room temperature, and the mod will still handle it when its resistance rises under heating. But if one could build a Ni200 coil of 0.9Ω, and then set TC to 250°C - not even its maximum - the resistance of that coil would rise to around 2.1Ω. Which is over the stated maximum VW ohms!

So I wonder what happens then. And whether they've even considered or tested for that, given how practically impossible it would be to get a Ni200 coil at 0.9Ω With Titanium it's certainly possible, but the lower TCR means it's unlikely to ever exceed 2.0Ω.

Actually, for Titanium it works out perfectly A 1.0Ω Titanium coil heated to 300°C increases its resistance to 1.98Ω! Just within the limit. But heat it to 315°C and it's 2.03Ω.

And although the DNA 40 stops at 300°C (or 315°C if you set it to 600°F), because it doesn't technically support Titanium and the temp settings heat a Titanium coil to more than specified, you could actually heat a Titanium coil to 380°C or so.

So I now really want to know what happens if you put a 1.0Ω coil on a DNA 40 and set the temp to, say, 250°C - which as we know from my probing will actually reach around 320°C, and therefore 2.05Ω That will take the coil over the maximum ohms of the mod. Will it just not heat it fully? Will it crash?

But anyway, yeah - with Titanium, as long as you keep your coil to 1.0Ω or less - which allows use of up to 8 wraps of 30G and should be the same of 32G x 2 twisted - you shouldn't have any practical problems within the normal vaping temperature range. And ditto Ni200 simply because it's impossible to build a usable coil at anywhere near the maximum ohms.

I bet that 1ohm limit is a legacy thing based purely on Ni where it would never be a problem...With Ti however, it easily could be!!

 

[TheotherSteveS]

How about quad 32g?? Its not that thick, probably about 26g maybe equivalent...

 

[TheBloke]

I also wonder if that 1.0Ω limit is actually enforced. With the DNA 40, which auto-detects between TC and non-TC (at least when TC is enabled), it's easy to imagine that it will simply not fire in TC with a >1.0Ω coil. In fact, that might one reason for the limitation - it's a handy way to ensure TC is never even attempted on plus-ohm (opposite of sub-ohm! ) Kanthal builds.

But what about a Yihi, or other mod that have dedicated TC and non-TC modes? The Yihi chips also state a max of 1.0Ω. Is that a guideline, or is it enforced?

Some time I will do a test.

 

[druckle]

I also wonder if that 1.0Ω limit is actually enforced. With the DNA 40, which auto-detects between TC and non-TC (at least when TC is enabled), it's easy to imagine that it will simply not fire in TC with a >1.0Ω coil. In fact, that might one reason for the limitation - it's a handy way to ensure TC is never even attempted on past-ohm Kanthal builds.

But what about a Yihi, or other mod that have dedicated TC and non-TC modes? The Yihi chips also state a max of 1.0Ω. Is that a guideline, or is it enforced?

Some time I will do a test.

I've had difficulty with DNA 40 correctly detecting TC mode with higher resistance coils and definitely like being able to set the device myself. The SXM always works from that standpoint especially with titanium wire.

Duane

 

[Madnapali]

Good info, bloke. My gennies are usually built on 5 wraps, probably around mesh that's just under 3mm... never actually measure the diameter. Most people do 3-4 wraps of kanthal but I need 5 in every single one of my gennies to hit .1ohms. Using twisted 32g titanium for four wraps will probably work out great and wind up being easier to build.

It will be a while before I have any titanium wire, but I shall report back with how it works on: Hellfire Shorty, Nahaulon, and NextGen. Possibly some others as a buddy of mine with some high ends just quit vaping and he is selling them cheap... It's tempting, but with a Shorty and a NextGen I really don't need another genny ever again haha.

 

[DejayRezme]

Well this thread really blew up lol. So much to read but quite a lot of very interesting info! I unfortuantely haven't been following so I want to ask a few questions:

1) The worksheet posted is very interesting but why can't I edit / copy it please? Without being able to see the contents of the cells it's hard to understand and to see what is actually calculated. Did you do own measurements to get these data or is this all from various datasheets? Thanks for sharing anyway.

2) So the TCR of nickel actually IS non linear in the temperature range of 0-200°C after all? Is the linear TCR value of 0.6% per degree really inaccurate then?

3) What is the difference between Nickel DH and NI200? Both have above 99% nickel. Are they really that different or what is up with that?

One idea I had is that with an open source chip like the Whiteout OS / Ares we might actually be able to attach a thermostor to an unused GPIO pin of the arduino board and measure these coefficients effortless and easily.

 

[Madnapali]

One idea I had is that with an open source chip like the Whiteout OS / Ares we might actually be able to attach a thermostor to an unused GPIO pin of the arduino board and measure these coefficients effortless and easily.

Dammit... I'm already gonna break my back writing custom code for the thing with very little free time and here you are giving me another way to spend more time on it hahaha.