Help Is it possible to calculate the wattage at which a coil / wick is likely to burn?

Not sure if this is possible but I've always wondered if there's a way to calculate the wattage for any given build at which you will almost certainly get a burnt coil / wick? I've used the various ohms law and Steam calculators but all those give (at least the way I've used them up to now) is the other variables in the equation for a given build. All well and good but I don't really want to know that (at least in this case).

As an example, I've just put a Kanthal A1 24 ga, 8 wrap (non spaced), 3.0mm coil in my Ammit 25 which comes in at 0.7 ohm and seems to vape well as low as 12-15W (at 15 it draws 3.24 v) which is fine for me as it it burns through batteries quite slowly, and juice. It doesn't spit and gurgle at this power range, start pushing it to 17, 20 and 22w and it starts to gurgle. I'm guessing that pushing it into the high 20s and 30s and it will almost certainly start to burn.

So, is there any way of calculating (even as only a rough guide) this maximum wattage? Of course everyone's tolerances of high temperatures will be different (and I suppose the one spanner in any calculations will be the juice type and PG/VG mix) but surely there must be some point at which you can almost be certain you will get that unmistakable mech/cotton fried taste. Reason I'm interested is mainly to get a good idea of just how high you might be able to push a build while doing the trial and error thing to get the best flavour (I have zero interest in cloud production, just taste) so as to avoid frying the cotton etc and having to re-wick.

Sorry if it's a dumb question, just can't find anything on it.

 

Hmmm. That might work, but for me, maybe lowering to 4v. Just tried it at 30w which came in at 4.5v and as I suspected, got the tinge of burnt taste. To pull 5v it would be at 35w which will DEFINITELY be sore throat mode. At 4v however it was 23w which is probably as high as I'd like it.

What I'll have to try and see is whether the equation would work across all builds. Still getting my head around this but would the equation need to change for a dual coil build, or because you know the resistance would it still be the same? Too much brain-work LOL. Will be really handy when changing tanks and being able to immediately see "That's WAY to high / low" for the recent change as with the tanks / builds I have now (and even now it's not that many!!), no way can I remember the range within it might need to be.

 

Indeed. Just tried it on the dual coil RDTA (24 ga, 8 wrap, 3mm - 0.4 ohm). Tried it at a couple of settings giving 3-3.5v and it was fine. Got it to pull 4v at 40w and that was burning. 30w comes in at 3.5v. Given that 4v was probably upper limit on the single coil RTA I might go with 3.5v as the starting point and work around that. Even 3v. It's just to give me an idea where I should be hovering round to avoid burning.

Update: The only area where it falls down a bit is on the Nautilus (and maybe all sub-ohm tanks with that style of coil) where the 1.85 ohm coils only need about 8-9w to reach 3.5v. That said I use the Nautilus very little these days, just don't seem to get the flavour from it compared to an RTA / RDTA, maybe they work better with a more tobacco style juice than the fruits. With the Nautilus about 4v comes in OK for me. On the flavour front with that I might just try a new coil and see again, other than that, can't see it getting much use. Might even sell it on. It's barely been used TBH

Getting there at least. Thanks for the help.

 

Actually it's more about DIY coils. The bit about the pre-builds only came in at the end where the equation falls down some.

The point with the DIY coils is finding some way to ID a rough no burn limit. It's not so much the resistance that the 'solution' centred around. It was more about an approximate voltage which of course will vary the wattage for any given resistance. Thus, for me, settling on approximately 3.5v the dual coil RDA will need about 30w, the single coil RTA around 15. So it's the voltage figure that's important in terms of what I'm looking for. Not so much the ohms.

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You need to re-read my comment. I was not saying "the resistance would be the same", indeed it's not even what I'm saying in the partial quote. Quoting the full sentence would assist more, (bold text used here to highlight the context):

"Still getting my head around this but would the equation need to change for a dual coil build, or because you know the resistance would it still be the same?"

The actual point is would the solution (e.g. a roughly 3.5v draw) change with a dual coild build or because you will know the resitance for that build (whatever it might be) would it (the equation / solution) be the same. Answer: It remains the same. Just use the 3.5v draw (in my case) as a rough guide, except where pre built sub-ohm coils are in use.

I have the app. Not bad. Yeah it's about finding a solution for me. If I ran that coil I talked about at 60w it wouldn't be a hot vape, it would be all smoked cotton and scorched metal. Things might change when I change coild material, not sure, we'll see. It might even need a different equation depending on coil material. Doubt it would given resitance is resistance but the wires I'm sure will be able to run hotter in some cases.

**Updated**

Yeah get that, the only point I was making WRT these coils is that the equation / solution seems to work better with DIY coil builds.

**Updated**

Final update on this. I think the RDTA burning out at (relatively) low watts (and and above a 3.5v draw) was probably down to poor wicking. It's a new tank so I'm still getting the hang of it. Wicked it again with wider cotton strips resulting in a thicker wick in the cotton and more bulk to the wicks above the tank and it seems to be holding and drawing juice better such that I can now easily vape it at 55w (4.75v) which, while that's a BIT hot for me, the wicks haven't burned at all, cotton still white. So it's coming along. Thanks @Siam Diesel and @debatedude for all the help with this. Can't do any more now, taste buds shot I think for tonight. Flavour is starting to hit where I want. Will try maybe even thicker wicks (slightly) tomorrow and maybe post a few deck shots for comments on the wicking.

**Updated**

PS: Above was MEANT to read "more wick in the coil", not "in the cotton". Seems once a post adds itself as an **Updated** to an older post, you can't get back it in to edit it again".

At this testing rate I think I'll need juice in gallon drums!!

 

Not sure what happened with the formatting above. All the DOUBLE POST entries and cramming up text make it a bit hard to read.

PS: Just noticed that the problem with the appearance of the above post only happens when viewing the thread on Tapatalk. Maybe a Tapatalk issue.