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

[DejayRezme]

Haha well hopefully we won't be the only ones experimenting with this I'd expect we'll see a lot of different firmware forks and experiments for all sort of crazy stuff.

 

[funkyrudi]

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.

A guy reported his TC Box ( can`t remember which one and where I read it ) automatically switched to VW mode, when he wanted to fire his 0,8 Ohm Titanium coil for the second time. His coil was still above 1 Ohm when he fired and his box didn´t ask for new/old coil, it just switched to VW.


Building higher Ohm coils is not a bad idea when you have to many atomizers on the shelf, but 0.6 Ohm should be high enough if you use it on your mech mod by accident.

 

[Madnapali]

Building higher Ohm coils is not a bad idea when you have to many atomizers on the shelf, but 0.6 Ohm should be high enough if you use it on your mech mod by accident.

I've heard a lot of people express that fear... Then there's me, with only two atomizers I don't use for TC... both of which are .1ohm or lower at all times lol.

 

[DejayRezme]

One thing I noticed on one of my mods (DNA40 clone) with a single resistherm 1.04 ohm coil was a warning on the screen saying "Ohms too high". Hilarious! Only during dry burn though and it still worked great. But this might be the cause of issues when ohms get too high you need higher voltages to power the coil. So if you hit the voltage limit the power is reduced.

 

[Madnapali]

One thing I noticed on one of my mods (DNA40 clone) with a single resistherm 1.04 ohm coil was a warning on the screen saying "Ohms too high". Hilarious! Only during dry burn though and it still worked great. But this might be the cause of issues when ohms get too high you need higher voltages to power the coil. So if you hit the voltage limit the power is reduced.

It was likely the upper limit of it's capability to calculate temperature for nickel. Had it known you were using Resistherm and had the right TCR curve, it probably wouldn't have been a problem.

 

[dr g]

It was likely the upper limit of it's capability to calculate temperature for nickel. Had it known you were using Resistherm and had the right TCR curve, it probably wouldn't have been a problem.

on a genuine dna40 that message indicates hitting converter output voltage limit. not sure whether it means the same on a clone.

 

[TheBloke]

One thing I noticed on one of my mods (DNA40 clone) with a single resistherm 1.04 ohm coil was a warning on the screen saying "Ohms too high". Hilarious! Only during dry burn though and it still worked great. But this might be the cause of issues when ohms get too high you need higher voltages to power the coil. So if you hit the voltage limit the power is reduced.

Which clone was that exactly?

Actually I think this makes sense. Let's say the clone has a 2.0Ω limit like the genuine does, which is very likely - the Rayn board basically copied the specs exactly, and nearly all clones are Rayn. Rayn and SXK are the two main chips out there. I think SXK copied the 2.0Ω upper limit as well.

OK so 2.0Ω limit, and you're dry burning. A 1.04Ω Resistherm coil will reach 2.0Ω at 308°C. It's entirely possible - even likely - that a dry coil being dry burned reaches in excess of 308°C.

As soon as it reached 308°C, the mod saw it was at/over 2.0Ω and had exceeded its hardcoded ohm limits. Hence it flashed the error.

So in fact it sounds like you already tested exactly what I described earlier - a 1.0Ω coil heated such that it reaches 2.0Ω or more to see what happens. I think we can say with some certainty that on your clone, what happens is it fires fine until it hits the 2.0Ω limit then it flashes an error. Makes sense. Probably once it reached 308°C it was firing a static voltage - whatever the voltage limit is - rather than adjusting the voltage for the increasing resistance.

It's interesting your coil was 1.04°C because that's just over the 1.0Ω stated maximum. So sounds like that clone does not enforce a 1.0Ω maximum for TC - which was my second question.

Thanks man, I think you just answered both my wonderings at once At least for the clone device - either Rayn or SXK, I'm assuming Rayn.

I'll test the authentic DNA 40 at some point - but from what Dr G said, it sounds like it will do exactly the same thing regarding the 2.0Ω upper limit; it'll hit the voltage limit, and then flash that message.

on a genuine dna40 that message indicates hitting converter output voltage limit. not sure whether it means the same on a clone.

Do you know whether the DNA 40 enforces the 1.0Ω limit for TC? Will it allow firing of a 1.01Ω build in TC or will it always switch to power mode if resistance is >1.0Ω - same as it does if it doesn't detect rising resistance?

 

[Almighty]

what would be the ideal ohm range for a dual coil with 317L for temp control ?

 

[TheBloke]

what would be the ideal ohm range for a dual coil with 317L for temp control ?

I don't think there is an 'ideal' resistance range as such. As long as it's within the range supported by the mod, resistance is a secondary factor.

The primary factors are:

1. How much power is required - generally, higher ohms = lower power = less battery usage = good thing
2. Response time - generally, lower ohms = faster response to power = quick vapour/heat-up = good thing
3. Coil mass - the greater the mass of metal, the more power required to heat it
4. Coil surface area - the greater the surface area, the more surface for juice to stick to = generally the better flavour

Dicodes in their Application Note For Temp Controlled Vaping suggest, for Ni70/Fe30 wire, an ohm range of 0.5Ω - 1.5Ω, which is pretty wide!

I would say that as long as you're under the 1.0Ω maximum on most TC mods, including your SXK, you can experiment with exact resistance according to tuning for the four parameters I mentioned above. There isn't a "right" answer. Find the compromise that suits you best. Personally I like a large surface area - thicker wire and often twisted wire - to maximise both flavour and usability. Thicker/twisted wire naturally pushes the resistance down, and increases the coil mass, which increases the power required. I don't worry too much about how much power/battery I'm using - I tend to vape at home, near a charger, I've long since given up counting how many hours I get out of a given battery/mod (and it is only hours, never days )

Going dual coil you're of course going to halve your ohms, so you're going to need each coil to be at least 0.2Ω, probably more, so that when it halves you're not too near the resistance minimum.

I guess with SS317 dual coil I'd tend to build two 0.5Ω - 1.0Ω coils, to give me a 0.25Ω - 0.5Ω final build. Depends on the thickness of wire I had, and whether I could do 3.0mm ID coils or not (as I usually prefer.)

• With 26G, a 3.0mm ID SS317 coil of 8 wraps is 0.64Ω.
• With 28G, 8 x 3.0mm wraps is about 0.98Ω.

I rarely build lower than 8 wraps if I can help it (again, more coil surface area = more flavour, theoretically!)

So for dual coil that would give a 0.3Ω - 0.5Ω range for the entire dual coil build. That sounds like a reasonable area for power - not super sub ohm and therefore very power hungry, but still low enough to get some good response times.

But as you can tell, a lot is down to taste and experimentation. There isn't really a target resistance you have to build for, so long as you're in the wide area of 0.1Ω - 1.0Ω.

 

[dr g]

Do you know whether the DNA 40 enforces the 1.0Ω limit for TC? Will it allow firing of a 1.01Ω build in TC or will it always switch to power mode if resistance is >1.0Ω - same as it does if it doesn't detect rising resistance?

The DNA40 does not enforce most limits, it soft limits, i.e. it will do the most it can with whatever it is given.

 

[TheBloke]

The DNA40 does not enforce most limits, it soft limits, i.e. it will do the most it can with whatever it is given.

OK.. but not sure this is a "soft limitable" thing? So you're saying that if I had a 1.1Ω coil build with TC enabled on a DNA 40 and fired, it would not switch out of TC?

 

[soulseek]

Why would a mod not have a lock into TC mode. The fact that people have problems with them popping out of TC mode because of an auto-sense failure would surely convince them to have one in place.

 

[TheBloke]

Why would a mod not have a lock into TC mode. The fact that people have problems with them popping out of TC mode because of an auto-sense failure would surely convince them to have one in place.

Agreed. As I just posted in the DNA 200 thread, auto sense is past its sell by date. I can understand that it sounded like a good idea at the time when they made the DNA 40, but it's not a good idea. Power and TC are very separate modes. There's been a number of times on my TC mods when I've wanted to fire in Power mode despite normally using TC - on a DNA 40 (and clones) ,that means I have to lock the mod, scroll through all the temp settings to OFF, unlock, do my power stuff, lock it again, scroll back to the temp I had before, unlock again.

Compare that to any of the other mods with proper modes, where I just go to the menu and change Power to TC and do my stuff, and when I go back again, my temperature (and locked resistance if I had one) is all remembered.

Far better, even in the normal use case - before you even consider autosensing sometimes not working, as you said.

If Evolv really think Autosense is a huge benefit and that a lot of people like it (I doubt they do), then they should offer three modes: Power; TC; Autosense. Allow the user to decide if they want an Auto mode, and allow them to lock into one or the other mode if they don't.

Actually, if you have to have an autosense mode, the way SXK implemented it is not bad: they did it very simply, by not having autosense at all. If you have TC on, it's always in TC. Then if you fire into a Kanthal coil, it simply sticks at your set watts - because the resistance never changes, so it thinks the coil is always at 68°F (or whatever your room temp is), nowhere near your setting. So no need to reduce watts.

It's probably not clean and neat enough for an expensive mod/chip to implement, but it works surprisingly well - allowing TC vaping and Kanthal vaping with no changes. Of course what it doesn't do is solve the problem of wanting to fire in Power mode even when you have a TC coil fitted (as one may well want to do with eg Resistherm/Alloy 120). So being able to set a specific mode is still best in my view.

 

[druckle]

Agreed. As I just posted in the DNA 200 thread, auto sense is past its sell by date. I can understand that it sounded like a good idea at the time when they made the DNA 40, but it's not a good idea. Power and TC are very separate modes. There's been a number of times on my TC mods when I've wanted to fire in Power mode despite normally using TC - on a DNA 40 (and clones) ,that means I have to lock the mod, scroll through all the temp settings to OFF, unlock, do my power stuff, lock it again, scroll back to the temp I had before, unlock again.

Compare that to any of the other mods with proper modes, where I just go to the menu and change Power to TC and do my stuff, and when I go back again, my temperature (and locked resistance if I had one) is all remembered.

Far better, even in the normal use case - before you even consider autosensing sometimes not working, as you said.

If Evolv really think Autosense is a huge benefit and that a lot of people like it (I doubt they do), then they should offer three modes: Power; TC; Autosense. Allow the user to decide if they want an Auto mode, and allow them to lock into one or the other mode if they don't.

Actually, if you have to have an autosense mode, the way SXK implemented it is not bad: they did it very simply, by not having autosense at all. If you have TC on, it's always in TC. Then if you fire into a Kanthal coil, it simply sticks at your set watts - because the resistance never changes, so it thinks the coil is always at 68°F (or whatever your room temp is), nowhere near your setting. So no need to reduce watts.

It's probably not clean and neat enough for an expensive mod/chip to implement, but it works surprisingly well - allowing TC vaping and Kanthal vaping with no changes. Of course what it doesn't do is solve the problem of wanting to fire in Power mode even when you have a TC coil fitted (as one may well want to do with eg Resistherm/Alloy 120). So being able to set a specific mode is still best in my view.

I absolutely agree with you.

The SXK method of locking resistance works fine. At first I wondered why it had to keep asking me if I put it down for an extended period but now that I'm really familiar with it I like the feature very much. Of course the SXM method is great too.

Duane

 

[dr g]

OK.. but not sure this is a "soft limitable" thing? So you're saying that if I had a 1.1Ω coil build with TC enabled on a DNA 40 and fired, it would not switch out of TC?

sure. you could fire as high as you like until it reaches the limits of the converter. i just fired a 4.22 ohm coil.

 

[TheBloke]

sure. you could fire as high as you like until it reaches the limits of the converter. i just fired a 4.22 ohm coil.

OK thanks. But how did you make a 4.22Ω TC coil?? For 30G Titanium that requires nearly 40 x 3.0mm wraps - is that what you did?

Or if you did that with Kanthal, then I don't think that tells us anything? because with Kanthal it switches out of TC anyway.

To be clear, my question is: can I make a >1.0Ω TC coil (Titanium, Ni200 if that were possible with Ni200), and fire it as a TC coil - not having it switch automatically to VW mode?

 

[dr g]

yes it was a tc coil. ni200 works, ti might not, depends on the gauge.

 

[vapealone]

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!

I dunno why Dicodes do things I haven't even heard about it before I came here. Patriotism maybe?

1. I do dry burn and make micro coils
2. The resistance listed on their page is definitely confusing It is two times higher than Ni. We have to look at μΩ/cm data which is: 19.95μΩ/cm Ni would be 9.6 μΩ/cm. I have listed Nifethal in my charts with 20.00μΩ/cm (=0.2 μΩ/m). With R28g=0.0247Ω/cm R26g=0.0155Ω/cm and R24g=0.0098Ω/cm so standard 10cm long build would be around 0.247-0.098Ω respectively
3. It is softer than Kanthal but definitely stronger than Ni. Actually it is very easy to work with. I like it more than Kanthal. You have to be a bit careful obviously but the result what I get on a Kuro is beautiful. I have to run now but later I can make some coils and take a few pix
4. I didn't tried on any VW but I am experimenting with TR vapes on mech mods but not with A120 generally (TM stands for Temperature Regulated here

 

[vapealone]

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.

@DejayRezme

1. It is the way Google sheet publishes and it suits me fine for now as I keep updating/refining the tables. The ρ(T) TFR(20°C-T) TCR(20°C-T) tabs are calculations the material tabs are acquired from sources given with links. However if you are interested in the formulas behind here is the tutorial
2. No, it is definitely not linear. And IMO any TCR number indicated without two reference number is useless. However, the most common TCR they generally provide is 0-100°C so if there is no number one may conclude that it is the nominal, 0-100°C TCR. But it is useless to us too
3. Dunno. Other elements present in the metal can modify properties.

 

[TheBloke]

yes it was a tc coil. ni200 works, ti might not, depends on the gauge.

Thanks, yes confirmed it works with Ti as well - 3.5Ω stretch of wire, TI 30 gauge.