Not my words but I just read this on the ft forum thought it interesting and might be useful to someone here so have just copied and pasted it:
"why anyone would want to match the resistance of Ni200? Ni200's low resistance is usually regarded as an unfortunate by product of using that wire, not an advantage.
Ni200 was chosen by Evolv as the first TC wire because it has a very high TCR (Temperature Coefficient of Resistance) and was already familiar to vapers. Titanium wasn't very well understood at the time and some thought it dangerous. But when temp controlled, Titanium is certainly no more dangerous than Ni200 and many think it safer.
The fact that Evolv chose Ni200 for the first TC technology by no means makes it the best TC wire. In my view it's in fact the worst.
Higher resistance is actually a key advantage of TC with Titanium (and other wires): building to a higher resistance enables a wider range of builds and wire gauges, improves TC accuracy (see next post,) and uses less power/battery for a given coil.
Other advantages over Ni200 are that it supports TC contact/micro coils, is generally a bit easier to work with, and some people also report better taste (though that's not something I've noticed personally.)
My Titanium single coils are usually in the range 0.35Ω - 0.50Ω. My preferred gauge is 26G, generally 8 or 9 wraps slightly spaced. I sometimes do contact/micro coils when that's more convenient for a deck.
So even dual coil I'm still above Ni200's range.
There's now a wide range of TC mods directly supporting Titanium, but as dilirium22 mentioned it can be used on any standard TC mod with a temperature offset. Here's the appropriate settings for the (authentic) DNA 40, derived from accurate temperature measurement as opposed to estimated from TCR; important on a DNA 40 because it doesn't use a single, flat TCR for Ni200. (Unlike other mods; see below):
Conversely, on my Yihi chip mods (SX Mini M, IPV4) in NI200 mode I used a temp of 135-150°C (275°F - 320°F). (But with firmware updates those mods now support Titanium.)
On the Rayn DNA 40 clones (eg Kangxin Mini VF) I use a similar range of 300 - 330°F. SXK DNA 40 clones can use Titanium without offset via a 'Nickel Purity' (TCR) setting of 35-40.
I haven't made a single Ni200 coil since I started with Titanium. It rocks.
Not that it's actually the best TC wire in my view - that honour goes to Resistherm NiFe30, AKA NiFethal 70, AKA Alloy 120. Available from Dicodes in 29G at €13/10m; dear but worth it. Its big advantage is that it can be dry burnt just like Kanthal. You can vape it in VW mode if you want, albeit with increasing resistance. Dry burning is great because it means the coil can be cleaned quickly with a dry burn, unlike Titanium and Ni200. It also means you can test a coil prior to vaping, checking it's glowing inside-out just like we did with Kanthal. Resistherm is highly recommended.
Another supporting dry burning is Stainless Steel (304; 316; 317.) Similar resistance to Titanium; very strong; cheap and available in several gauges. Unfortunately its TCR at the lower edge of current accurate TC. As such it can only be TC vaped on a mod that supports adjusting TCR down to its level of 0.001 (vs Ni200's 0.006, Titanium's 0.0035 and Resistherm's 0.0032.) Mods that support this are the Dicodes chip (2380, Dani Extreme v2, Pipeline Pro 2), DNA 200, and SXK's DNA 40 clones with Nickel Purity feature. (The Smok XCube 2 also supports TCR adjustment but does not currently allow setting TCR low enough - it only goes to 0.0015, 50% too high. There's a chance they might add it in a FW update.)
There's another point regarding resistance that's worth mentioning:
A higher base resistance improves overall TC accuracy in situations where the resistance reading is not 100% accurate - which is every real-life TC vaping situation, to a greater or lesser extent.
There is always inaccuracy even assuming a 100% accurate mod, because every atomizer adds some Static Resistance (SR). Every atomizer itself has some resistance which the mod detects alongside the coil.
If one had a highly accurate ohm reader and measured a coil on its own, it might measure let's say 0.20Ω. Then one puts that coil in an atomizer and attaches it to the mod and the mod reads the resistance. The mod (which we'll assume for the moment is also highly accurate) measures the coil as 0.21Ω. That means the atomizer has added 0.01Ω of static resistance. That's not an uncommon figure in real life situations and some atomizers (most notoriously Kayfun v4s with their spring) can go even higher. In some tests even having dirty screws has been known to add 0.01Ω on its own!
Base resistance is a multiplicative factor in the TCR calculations. Therefore it matters how high the base resistance is, and more importantly it matters how big the resistance error is as a percentage of the base resistance.
In other words: the higher the base resistance of the coil the lower the percentage error of any static resistance, and therefore the more accurate the TC.
Here's an example of how that affects the accuracy, with two different base coil resistances. This TCR calculator is used for the measurements.
* Ni200 coil @ 0.12Ω, Titanium @ 0.50Ω
* Vaped in an atomizer with SR of 0.01Ω
* 0.12Ω Ni200 coil:
** Calc 1, the actual coil:
*** Base Ω: 0.12Ω
*** 20°C -> 232°C
*** End Ω: 0.27264Ω
** Calc 2, as done on mod with atty having 0.01Ω SR:
*** Base Ω: 0.13Ω (0.12Ω + 0.01Ω)
*** End Ω: 0.28264Ω (0.27264Ω + 0.01Ω)
*** 20°C -> 215.7°C
** The SR of this atty with a 0.12Ω coil causes a coil heated to 232°C (450°F) to read on the mod as 215.7°C. If the mod set temp is 230°C (450°F) the mod will continue to power it past that, likely to around 245°C / 470°F. It will think the coil has reached the target of 230°C when it's actually at 246°C.
* 0.50Ω Titanium coil:
** Calc 1, the actual coil:
*** Base Ω: 0.50Ω
*** 20°C -> 232°C
*** End Ω: 0.881Ω
** Calc 2, as done on mod with atty having 0.01Ω SR:
*** Base Ω: 0.51Ω (0.50Ω + 0.01Ω)
*** End Ω: 0.891Ω (0.881Ω + 0.01Ω)
*** 20°C -> 227.8°C
** The 0.50Ω coil with 0.01Ω SR, when heated to 232°C (450°F), reads on the mod as 227.8°C.
** Clearly better: only 4.2°C out, compared to 16.3°C.
I showed a low resistance Ni200 coil versus a high resistance Titanium coil. The numbers are almost identical when both are the same material (eg both coils Ni200.) A 0.50Ω Ni200 coil vs a 0.12Ω Ni200 coil is again approximately 4°C of inaccuracy vs 16°C.
TLDR: Titanium in a real life TC situation is usually slightly more accurate than Ni200, because higher base resistances are standard.
The same applies to Resistherm and Stainless Steel, because they also have higher resistances than Ni200. Resistherm resistance is a bit lower than Titanium, Stainless Steel a bit higher.
The wire itself actually has very little effect in this calc. It's all about the coil base resistance: when considering errors in TC resistance measurements, base resistance is king. The higher the better.
Note that that I'm not suggesting building to a higher resistance just for accuracy, nor am I suggesting that 16°C inaccuracy is terrible. But all improved accuracy is good, and this is an automatic win with the higher resistance TC wires.
Higher resistance wire is better overall, others things being equal. But things are not equal: Titanium (and Resistherm) are already better in most every other respect! An all round win
