Optimal Sub-Ohm Resistance

[Lastlokean]

My experience dictates so far that a ~.7 ohm coil is ideal for a quality with long battery life.

.6 ohms is a good compromise with slightly better performance... I personally seem to get a little burning off of a freshly charged battery though.

Anything lower than .5 really destroys battery life and generally seems to taste burnt.

Anything over .7 ohms for me personally seems really unsatisfying.


(can't remember where I found this chart... but it seems to agree with my findings)

Anyone care to Dis/Agree?

 

[Innocuous]

Anything under 1Ω works pretty nicely for me.. My meter lies by .4, and anything between 1.4 and a reading of 1Ω vapes quite well. Mind you, this is 28awg, .4 and .7 ribbon. This is all on mechs, single cell, and day in and out - AW 18500's or CGR's.

With a target of .7Ω: .8, or .9 still satisfy.

 

[Lastlokean]

Well sure 1.0 ohms will vape quite well on a fresh cell... That is at 18 watts. But will you need to change the cell way before 3.6 volts and 13 watts? While a coil at exactly .70 ohms will vape like a champion from 4.2 volts all the way down to 3.6...

If your meter lies by .4 how do you eve know if your coil is safe when doing sub-ohm builds? If your going for a .5 ohm dual coil and your meter says .5 you could actually have something dangerous built (.1 ohms and 90 watts per coil), something as intended, or something way under powered (.9 ohms at 9.8 watts per coil...) or anywhere between...

 

[pdib]

I think it's like hot sauce. Give it time.

 

[UncleChuck]

Obviously personal taste varies, but I tend to agree, with a single coil, 28g Kanthal, around .7 gives you the best performance. Lower starts to burn, higher gets slower with warm up time.

With 26g, however, I find the sweet spot to be .5, any lower and it burns, higher and slower heat up times. With 30g a 1ohm coil seems to be the sweet spot, with the same results if higher/lower.

26g - .5 ohh ~ 30 Watts
28g - .7 ohm ~ 20 Watts
30g - 1 ohm ~ 15 Watts

 

[desk1%]

View attachment 278983

Anyone care to Dis/Agree?

What are the junction figures representative of. They don't represent P or I.

 

[Dpb1983]

(Voltage X Voltage) / Resistance = power in watts

 

[Vaslovik]

For me .8 ohm is the sweet spot. I suspect it's really a matter of personal preference and individual build technique.

 

[desk1%]

(Voltage X Voltage) / Resistance = power in watts

While close, why designate 'V' and 'R' to the tenth but 'P' stay's rounded to the nearest whole nuber? IMO this table is dangerous when it comes to figuring 'I'. In the R=1.0 area you end up with a 92 mA difference in 'I' which could be the make or break on a build. But then again if you're trusting a table from the internet to configure a mod you may deserve what's coming.

 

[Dpb1983]

While close, why designate 'V' and 'R' to the tenth but 'P' stay's rounded to the nearest whole nuber? IMO this table is dangerous when it comes to figuring 'I'. In the R=1.0 area you end up with a 92 mA difference in 'I' which could be the make or break on a build. But then again if you're trusting a table from the internet to configure a mod you may deserve what's coming.

I agree 100%. Ohms law does not round numbers, neither should the modder. Get a decent multimeter and do the math.

 

[pdib]

Yeah, so, what Uncle Chuck was saying got me thinking. We think so much in terms of the resistance of our coil, and the power that produces; we kind of forget some simple stuff. The reason the fatter wire has lower resistance is simply because there's more of it. It's only getting "hotter" because there's more of it. It's actually getting "more" rather than hotter. Given sufficient juice to utilize that "more", we are simply vaporizing more liquid. Given sufficient airflow to draw the proportionate amount across our little steam generator, we are simply producing more steam. In fact, depending on one's build, I imagine the temp. of the vape and the quality of it can be exactly the same at .5Ω as at 2Ω . . . . . . . . just more of it. It really all just comes down to building/wicking/airflow in the right proportions. All this would only be limited by the size of our atomizers. I couldn't accomplish the same vape with an enormous coil and a car battery (inside that same atomizer). But I've done enough experimenting to know that .3Ω - 3Ω can all work inside that little doo-dad.

 

[Alexander Mundy]

Short answer IMO is that there isn't an optimal resistance.
(I think what dibby was getting at)
In each setup there are many factors to an optimal resistance and they are all interrelated in an intricate dance with each other.
On the ends of that spectrum I have one setup that I find .4 ohms is about optimal, and another that is .9 ohms.

Some of the factors I can think of (in no certain order):

Battery internal resistance.
More power available with lower internal resistance.

Mod & Atty resistance.
Ditto with available power.

Air flow.
Not only the amount but a bazillion different variables with positioning and chamber etc affect vapor, throat hit, warmth, taste, and about any other quality of vape and will require different resistances to optimize.

The relation of the coil surface area to the amount of heat energy available at that surface area.
This involves the resistivity of the coil material, the percentage of surface area exposed, and the power per surface area unit (which also involves the voltage at the coil).
This one is often not thought about but can make a huge difference in all the qualities of vape also.
This is why there is a different vape with a multiple wire twisted coil with almost the same resistance as a single larger wire non twisted coil.
IMO this is a crucial element in the dance and the one that needs changed the most across that .3 to 3 ohm range dibby was talking about to get that same vape.
This is the element I was trying to optimize with my magic wire.
If only resistance wire was available in different cross sectional shapes and also available hollow like tubing I think we could advance this factor even further.

Wicking ability.
How much liquid is on the surface of the coil (and evenness of) during the complete vaping draw is crucial.
You have to have enough to vaporize, but not too much.

Eliquid.
Flavoring amount and type, PG/VG ratio, and nic content.
I have different juices that I prefer with different coil setups.

Personal taste.
Even given the same battery, mod, atty, wire, position, wick, etc. what I think is the optimal resistance is about 1-1/2 times what the bumblebee and oragatang prefer. Compounding that further in that particular circumstance, I have about 1-1/2 times as much exposed coil area so the heat to surface area differential is over 2 times different.

So it comes down to what your preference is for your particular setup at that time.

 

[bender817]

I run a quad nano in an igo-w @ .34 ohms and I have a crazy friend that built one with less wraps @ .17 ohms. They are both crazy and dangerous (mine is 58.8w/12.35A on a full batt) but with the right batteries its not gonna detonate. Its a delicious hot vape. Nothing compares.

Sent from my SAMSUNG-SGH-I747 using Tapatalk

 

[desk1%]

I run a quad nano in an igo-w @ .34 ohms and I have a crazy friend that built one with less wraps @ .17 ohms. They are both crazy and dangerous (mine is 58.8w/12.35A on a full batt)

You may want to double and triple check your math. P=51.9(51.88) but I=12.35 One mistake in engineering could result in a bad burn.

 

[bender817]

Yeah typo. My bad. Still a crazy vape.

 

[dice57]

So much depends on the atomizer, building skills, wick and air potential. I build for the rba. Try to use as much area available between the posts while keeping ohms at 0.7 ohms or lower. I use different twisted combos to achieve this. Have a few rba's that perform exceptionally well down around 0.2 ohms, some that function well at any ohm build so will usually shoot for 0.5-0.7 ohms so that I will get a great vape whether I fire it with a Mech or regulated mod.

If I'm getting dry hits or burned flavor, am either out of juice or I fraked my build and wick up.