TC with 316L SS at 22AWG not working?

[8HRR52J]

(New to the forum (but not to vaping) Tried to get this in the right thread!) - sorry for the essay in advance!

I have a Smok X cube ultra 220w (can adjust TCR and is SS TC compatible) and I am using 0.6mm SS 316L wire from stealth vapes. I am experiencing problems on 2 of my RDAs and on the RBA of the smok TFV8.

The builds are all dual coil, spaced, approx 8-11 wraps (per coil) and come out around 0.2ohms (0.14, 0.22 and 0.27 in the 3 different tanks.) The TCR value is set to 0.00092 (as I understand it should be for SS 316L?)
(All the tanks initial resistances are set on the device when they are cold)

The problem is extremely inconsistent temperature readings ie: vaping at any set temp will just cause the mod to give it constant power (as if in power mode) and will not decrease the power or shut it off as it should. The mod is also reading the current coil temp as 25*C constantly (even though its being bombarded with like 70W for 3 seconds!)

Then, sometimes, the complete opposite happens; a nearly cold coil won't fire at all (ok, so the mod gives it something ridiculous like 0.5W at 0.4V) and the temp protection sign comes on. frustrating much!?

I also have 2 (original) kanger subtanks both using 24 guage 316L SS (TCR set at 0.00092, again) with about 8 wraps (spaced and ofc. only single coils) with both tanks reading about 0.3ohms and both work in TC mode flawlessly! never had a burnt hit, wattage decreases smoothly and consistently as the coils heat up - it's brilliant, just a shame the tank's airflow and wicking is so shit!!!

Pictures uploaded show the 2 subtank RBAs on the left (burnt out from a week's use) 2 drippers in the middle and the TFV8 RBA last. The last 2 images are screenshots of the TFV8 firing... and stuck at 25*C. FFS!!

I've given all the details I could possibly think of - so hopefully someone will know straight away what I am doing wrong!! - does TC work on dual coil builds? does it not work on wires lower than 24 AWG? I can't think of any reason why it wouldn't though.

thanks guys - look forward to reading your ideas!

 

[Mr Numpty]

@8HRR52J I think you may be suffering on two fronts. Firstly, 22 gauge will be tough to get a high enough resistance with. 316SS has a poor TCR curve so needs a fairly high resistance to provide semi-accurate TC. 0.3 Ohms and up should perhaps be considered a minimum to aim for. Having said that, I'd have thought your 0.27 set up should be performing a bit better than you describe, which might be the 2nd problem - that Smok mods are not terribly good at TC. At any rate, for dual coil set ups with 316SS, I tend to use 26 gauge, so you might find better performance with that.

I have no idea why it is showing a 25C reading. That's odd.

 

[Mr Numpty]

Not sure about your TCR setting there. My TC mods tend to just use 4 figures so I have 316SS set to 0088 (TCR of 316LSS is 879 ×10-6) but not sure how many zeros that means you should have in your settings there. Is it possible you are missing a zero?

 

[Simon G]

man, that is some seriously thick wire.

I'd use 28awg in those smaller decks especially. ... 26awg in the others.

 

[Arctic_Wolf]

Indeed, way to thick a gauge of wire for TC on any device, let alone the SMOK . Use 3mm or 4mm tops.

Your SMOK already has TC SS preprogrammed in and whilst not considered the best available it's still better than using manual TCR. What's making you use TCR over SMOK's TC SS curve??

 

[Tubbyengineer]

OK, I'm seeing two problems here, they've both been mentioned but I'll bring them together for you. Firstly your wire is far too thick, your building a coil not trying to tether the USS Missouri, try using 26 or 28 Gauge, Secondly you're using the TCR setting and unless I'm very much mistaken you're using the wrong TCR Value, Smok mods tend to have an SS TC Mode built in so try to stick with that but failing that heres a screen capture of the Steam Engine Wire Wizard info Panel for SS316L/Elite.
For those who arent sure 879x10-6 means move the decimal point 6 places left so 879 becomes 0.000879

 

[8HRR52J]

Indeed, way to thick a gauge of wire for TC on any device, let alone the SMOK . Use 3mm or 4mm tops.

Your SMOK already has TC SS preprogrammed in and whilst not considered the best available it's still better than using manual TCR. What's making you use TCR over SMOK's TC SS curve??

yeah i think i'll redo the coils with 24/26 guage and see if it helps.

I didn't purposely choose TCR on the smok; when you choose temp mode it asks for the initial ramp up power (low, soft normal etc..) then the coil type and then the next screen asks you to set the TCR of the SS you're using. There isn't any way to just select SS/Ni/Ti without also setting the TCR - which is good i thought, because of all the different types of SS// available. The TCR for SS was already set at 0.00092 from factory too.

but seeing as it works so well in the kangers and i'm using 24 guage, it's probably the thicker wire that's throwing the TC off.

I wanted thick wire though, because I assumed you can put more power through it (as it has a lower resistance) and has more contact with the cotton so would produce more flavour and vapour too, unless i'm wrong - somebody feel free to bring me up to speed!!

 

[Mr Numpty]

I wanted thick wire though, because I assumed you can put more power through it (as it has a lower resistance) and has more contact with the cotton so would produce more flavour and vapour too, unless i'm wrong - somebody feel free to bring me up to speed!!

That's all true enough if you're vaping in power mode, but in TC mode the wattage is largely irrelevant because whatever you set it to, the mod will cut back on the wattage as soon as the coils reach the set temperature. The wattage only determines how quickly it ramps up to that set temp and even then, setting it too high can cause too much of a rebound, resulting in a less smooth vape.
For thicker wires you probably would need to use a higher wattage than for thinner wires for a quick ramp up, but as previously mentioned, effective TC vaping is often more about having your resistance in the best range, which will be very difficult in dual coil builds with 22/24 gauge.

 

[8HRR52J]

OK, I'm seeing two problems here, they've both been mentioned but I'll bring them together for you. Firstly your wire is far too thick, your building a coil not trying to tether the USS Missouri, try using 26 or 28 Gauge, Secondly you're using the TCR setting and unless I'm very much mistaken you're using the wrong TCR Value, Smok mods tend to have an SS TC Mode built in so try to stick with that but failing that heres a screen capture of the Steam Engine Wire Wizard info Panel for SS316L/Elite.
For those who arent sure 879x10-6 means move the decimal point 6 places left so 879 becomes 0.000879
View attachment 117905

Thanks! The wire wizard is quite helpful...

I thought i would input the dual coil setup in the TFV8 i have and these are the results:

The TCR value on steam engine seems to be wrong though? 0.000879 doesn't correspond to any of the 316L values posted on forums....
https://www.reddit.com/r/electronic...t_should_i_set_the_tcr_to_for_316l_stainless/

but i'll give it a go at all the different numbers people have suggested and see if that helps.
also, the TC precision of the setup I have seems very low (still not quite sure what I compare this value to though)

and the final resistance of the coils i'm reading is 0.27 by the smok and by my sigelei. On steam it shows 0.14 ohms... so maybe one of the coils lost connection... I'll take it apart again when I can be bothered and see what's going on!

thanks for your replies guys!

 

[Tubbyengineer]

Wire wizard is good for sorting out individual coils but to get a good idea of what a build will come out like use the Coil Wrapping tab on Steam Engine, This is the kind of build I'd suggest for a TC setup using SS316L
As for Steam engine's SS 316 TCR being wrong - I'd suggest it's unlikely, I get good results using those same values on DNA mods, It's more likely to be differences between devices thats the cause, best thing to do is to play around with the TCR if you don't seem to be getting the right results, but before you do that you should make sure you've eliminated the "Standard" causes of poor performance, such as shorting, hot spots and too much / too little wicking...