The relationship between resistance and wattage
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Further from Kickingthesticks point, lower resistance builds often needs more wattage, but only as a guideline.
In general there is no direct relationship between the two. Imagine I showed you a hill and asked you how much power would a vehicle need to get up that hill then you'd immediately ask "what kind of vehicle"?
A scooter, a small car, a truck, a big rig all would need different levels of power because of their weight.
Basically the same is true for our coils, the higher the mass the more power it takes to get it "up the hill" to your desired vaping experience.
Since we're using different materials with different resistances this is the only general rule that holds, two coils could have the exact same resistance but wildly different mass and so would need different levels of power.
It gets a little easier if you choose only one material and compare coils built only of that one, then what Violetti says applies because in that case "lower" really means "more mass".
But what "low" and "high" means is different for each material.
For a single Kanthal coil 1Ω would be kind of low while the same mass stainless steel coil would be around 0.5Ω and again the same mass Titanium around 0.3Ω (all 26g). You could fire all of those at 20W-25W (the Titanium one only in TC but that's another story).
A scooter, a small car, a truck, a big rig all would need different levels of power because of their weight.
Basically the same is true for our coils, the higher the mass the more power it takes to get it "up the hill" to your desired vaping experience.
Since we're using different materials with different resistances this is the only general rule that holds, two coils could have the exact same resistance but wildly different mass and so would need different levels of power.
It gets a little easier if you choose only one material and compare coils built only of that one, then what Violetti says applies because in that case "lower" really means "more mass".
But what "low" and "high" means is different for each material.
For a single Kanthal coil 1Ω would be kind of low while the same mass stainless steel coil would be around 0.5Ω and again the same mass Titanium around 0.3Ω (all 26g). You could fire all of those at 20W-25W (the Titanium one only in TC but that's another story).
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There is also a website that'll let you calculate a good ballpark power setting depending on material, wire gauge and resistance of your coil
Coil wrapping | Steam Engine | free vaping calculators
(it has a tab located on the top for more complex coils, called "wire wizard")
Coil wrapping | Steam Engine | free vaping calculators
(it has a tab located on the top for more complex coils, called "wire wizard")
Lower resistance always needs more power for heat. When you reduce resistance the coil isnt getting as hot. Heat is a byproduct of electrical current flowing through a conductor.
Have you ever tested that hypothesis? Like built 2 identical coils, let's say Kanthal and SS316, 26g 6 wraps.
Not only has the SS coil lower resistance but also higher heat capacity, so in theory it should behave more lazily than the Kanthal coil, right?
I thought the same once until I actually did the experiment (repeated about 24 times, with letting the above coils cool inbetween), fired with extremely low power to pronounce the effect (10W) and got an average of 4s for Kanthal to glow dark red and 3.4s for the SS. Same mod and atomizer of course and changed coils 3 times (so there were 3 Kanthal and 3 SS coils, each fired 8 times).
I can't explain the result though, it's counterintuitive to say the least and goes against what I have learned in my physics courses
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If you're using exotic coils that's not always the case. I found that juggernaut coils require more power than super-juggernaut coils to get to temperature, which require more than framed twisted staple coils, all of equal resistance, so if you were changing from 0.2ohm juggernaut coils to 0.15ohm framed twisted staples you might not need as much power even though the resistance has decreased.
AgreedHave you ever tested that hypothesis? Like built 2 identical coils, let's say Kanthal and SS316, 26g 6 wraps.
Not only has the SS coil lower resistance but also higher heat capacity, so in theory it should behave more lazily than the Kanthal coil, right?
I thought the same once until I actually did the experiment (repeated about 24 times, with letting the above coils cool inbetween), fired with extremely low power to pronounce the effect (10W) and got an average of 4s for Kanthal to glow dark red and and 3.4s for the SS. Same mod and atomizer of course and changed coils 3 times (so there were 3 Kanthal and 3 SS coils, each fired 8 times).
I can't explain the result though, it's counterintuitive to say the least and goes against what I have learned in my physics courses
If by Physics 101 you mean the kind of physics where cows are assumed to be spherical then sure, but you're ignoring factors. If you're reducing the resistance by keeping all variables the same and reducing the number of wraps then sure, but with exotic coil builds other factors come into play. The easiest example is that a clapton coil will require more power to heat the outer wire than an equal resistance plain wire because the outer wire doesn't have much influence on the overall resistance. You could reduce the resistance of the plain wire by reducing the number of wraps and still need less power than the clapton. It's Physics, past the introductory course
Estimates, charts, calculators and analogies are all fine for rough starting points.
The only way for you to find the 'best' wattage for any 'coil' no matter the resistance is to start at a low power setting & gradually work your way up taking a few vapes on each setting until you find what you like best.
There are far too many variables to consider beyond power / resistance that effect vape quality to give a direct even semi accurate answer.
What watt setting is 'best' with what Ω = different for each individual.
30w with a .5Ω 'coil' will give all sorts of differing results depending on too many variables to list.
inhale method/airflow, pg/vg ratio, wire type, coil type, coil mass, various flavorings & sweeteners etc.. all have an effect.
What power range an individual uses on any given 'coil' is a matter of personal preference / what tastes best to that person.
The only way for you to find the 'best' wattage for any 'coil' no matter the resistance is to start at a low power setting & gradually work your way up taking a few vapes on each setting until you find what you like best.
There are far too many variables to consider beyond power / resistance that effect vape quality to give a direct even semi accurate answer.
What watt setting is 'best' with what Ω = different for each individual.
30w with a .5Ω 'coil' will give all sorts of differing results depending on too many variables to list.
inhale method/airflow, pg/vg ratio, wire type, coil type, coil mass, various flavorings & sweeteners etc.. all have an effect.
What power range an individual uses on any given 'coil' is a matter of personal preference / what tastes best to that person.
No one has mentioned surface area. It's a big factor that has to be taken into consideration. It's easy enough to make a 1 ohm coil that has twice the surface area of a 0.5 ohm coil. In that case, the 1 ohm coil will require roughly double the power.
This leads to the concept of heat flux, where we calculate the power per unit of coil area. Unfortunately, the most commonly used tool (SteamEngine) gets this wrong for most complex builds that consist of more than one strand of wire.
This leads to the concept of heat flux, where we calculate the power per unit of coil area. Unfortunately, the most commonly used tool (SteamEngine) gets this wrong for most complex builds that consist of more than one strand of wire.
Build two coils using the same diameter with the same wire type and gauge. Build one with enough wraps to achieve 0.50 Ohms and the other to achieve 1.0 Ohms.
The coil with the higher resistance will require more power to achieve the same temperature because it has more metal mass and therefore a higher heat
The notion that higher resistance always and everywhere requires less power is a misconception held over from the times when vaping at more than 10 Watts was considered a dangerous fad.
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Heat flux is watts per unit of surface area. Mass does enter into a heat flux calculation at all.
I have always used the Steam Engine heat flux calculator as a relative value rather than an precise value. I use simple one wire, one coil builds. I still use the "old" style calculator, never change the wattage and figure that if wrong, the error will be a consistent error within the narrow confines of my build. I essentially build to get a certain range of heat flux.
Like most of my life, I may frequently be wrong but my errors are consistent and, so, predictable.
It's fine for single wire builds, and probably not far off for straight parallel builds. But the moment you twist wires together in any way, e.g. multiple strands tightly twisted, or Claptons, or whatever, it's significantly off because it uses the total wire surface area and fails to account for the fact that one wire "shields" another.
The main thing is, if you like the vape youre getting with whatever coil configuration, wattage setting, and all the other variables, then you are doing it right. Thats what matters in the end.
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