Why wattage, what we care about is current!

[GoBlue88]

and all this time I thought the resistance increased as the wire becomes heated....

Right you are, wrong I was

 

[Boden]

We should set mods to BTUs not watts.


*runs away*

 

[tj99959]

You guys just need to learn how to run the numbers
Obtaining the ideal air fuel ratio is what's most important.

oh-wait .... that's for pump gas

 

[zapped]

Take equation (3). You run a VW device at a high wattage , but a very high resistance. That's could actually be a really low vapor production/ cool vape, because your current would be small. So your doing tons of electrical work (using battery life), but not producing much current, and therefore not producing much vapor, and relatively cool vapor.

Higher resistance equals lower drain rates on your battery.

Think of a faucet; if you turn it all the way open (lower resistance) a higher volume of water comes out at a faster rate and you will eventually drain your well.

Now turn the faucet to the right a few times (higher resistance) less water comes out and at a slower rate so the well takes longer to drain.

Batteries work the same way.

I get significantly longer battery life using 3.0 ohm cartos versus 2.0hm cartos and thats using the same watts.

Its also why sub ohm builds can be dangerous without using a vape-safe fuse and high drain batteries.

 

[zapped]

double post

 

[DaveSignal]

ETA: current does come into play on the limitations of the mod. My Sigelei 100W can't reach 100W with any resistance I throw on it. There are both current and voltage limitations. So one needs to look at their mods specs and do the math to determine what resistances can be used to reach maximum power, if that matters to you. I don't vape at 100W so I don't care much. I might check when I'm bored

According to steam engine it requires a resistance between 0.15 and 0.49 ohm.

 

[Hans Wermhat]

That's WAY too much to read. Lol! Mod makers started using VW because it is the most sensitive increment. 1/10th of a watt is a smaller adjustment than 1/10th of a volt. It gives the user the most control over a precisely fine tuned vape.

 

[roxynoodle]

According to steam engine it requires a resistance between 0.15 and 0.49 ohm.

I believe I worked it out once . For the heck of it. Its never been over 60W though. I'm not very adventurous in my vaping.

 

[Alien Traveler]

Of all the numbers thrown around, heat flux is not mentioned anywhere near as much as it should be. It's the single biggest factor in my builds. Wicking is probably the most difficult part to get right for me btw.

I strongly believe that a therm "heat flux" is wrongly used in vaping term which purpose is mostly to make things look somewhat scientific. I did not look through "vaping literature" too thoroughly, may be I've missed something, but for now I see it as an equivalent to just thermal energy generated by coils, which (about) exactly is wattage. No difference.

 

[Boden]

That's WAY too much to read. Lol! Mod makers started using VW because it is the most sensitive increment. 1/10th of a watt is a smaller adjustment than 1/10th of a volt. It gives the user the most control over a precisely fine tuned vape.

They started using watts because you could set a power supply to watts and no matter what ohm coil you put on it, it would auto calculate the voltage needed to hit that target output.

 

[tj99959]

Using VW just takes the need to use your brain out of the equation is all.

 

[suprtrkr]

We should set mods to BTUs not watts.


*runs away*

Oh, I dunno about that, but I wouldn't mind seeing battery capacities rated in watt/hours...

 

[crxess]

Its also why sub ohm builds can be dangerous without using a vape-safe fuse and high drain batteries.

If that came from a politicization it could be considered an inflammatory statement to gain support against Vaping.
.8ohm is Sub ohm and pretty Safe for IMR Batteries to handle, even 10a IMR's
Sony VTC5 18650's present no problem or even warming much at .5ohm
TC Mods are Safely running .05ohm resistance devices on 20a IMR Batteries.

We do not need to reinforce the other Camps practices.

I'm not saying your statement is incorrect, simply it is vague and open ended.
Kind of like Regulating (Just in Case) vaping might be found harmful.

 

[yuseffuhler]

I strongly believe that a therm "heat flux" is wrongly used in vaping term which purpose is mostly to make things look somewhat scientific. I did not look through "vaping literature" too thoroughly, may be I've missed something, but for now I see it as an equivalent to just thermal energy generated by coils, which (about) exactly is wattage. No difference.

It's a function of watts and surface area. So if you have a .4 ohm 24 gauge dual coil with a 3 mm id, it'll have a heat flux of 276 mw/mm2 at 100 watts. This is a nice warm vape. If you have the same resistance, .4 ohms, with 28 gauge kanthal is 1109 mw/mm2, a burning hot terrible vape. Catching your wick on fire, etc.

 

[crxess]

It's a function of watts and surface area. So if you have a .4 ohm 24 gauge dual coil with a 3 mm id, it'll have a heat flux of 276 mw/mm2 at 100 watts. This is a nice warm vape. If you have the same resistance, .4 ohms, with 28 gauge kanthal is 1109 mw/mm2, a burning hot terrible vape. Catching your wick on fire, etc.

Only in Strict Mechanical terms.
I Vape .4ohm 28ga. coils often. Regulated to 25/30w depending on final wicking and e-liquid.
No HOT Vapes
NO Terrible Vape
NEVER a Burning Coil
Much longer Battery life from quicker heat up
Much quicker cool down
More wraps for better coverage and dispersion

Caveman with club become proficient - kill beast
Modern man with Grill Cook beast and party

 

[yuseffuhler]

Only in Strict Mechanical terms.
I Vape .4ohm 28ga. coils often. Regulated to 25/30w depending on final wicking and e-liquid.
No HOT Vapes
NO Terrible Vape
NEVER a Burning Coil
Much longer Battery life from quicker heat up
Much quicker cool down
More wraps for better coverage and dispersion

Caveman with club become proficient - kill beast
Modern man with Grill Cook beast and party

That example should have stated 100 watts for both coils, my bad lol. At 30 watts, you're running around 300 mw/mm2. Almost the same heat flux as the 24 gauge dual coil i mentioned earlier. Also, 24 gauge requires more wraps because it's a lower resistance wire.

 

[Alien Traveler]

It's a function of watts and surface area. So if you have a .4 ohm 24 gauge dual coil with a 3 mm id, it'll have a heat flux of 276 mw/mm2 at 100 watts. This is a nice warm vape. If you have the same resistance, .4 ohms, with 28 gauge kanthal is 1109 mw/mm2, a burning hot terrible vape. Catching your wick on fire, etc.

Now I see what it is about. But what you are talking about is not a heat flux, but - very approximately - a heat flux density, or heat rate per unit area. And "heat rate per unit area" describes things in much more understandable way than incorrectly used "heat flux".
What's more, we all know we cannot use just watts, "heat flux" or other single parameter to compare different builds.

 

[tj99959]

Now I see what it is about. But what you are talking about is not a heat flux, but - very approximately - a heat flux density, or heat rate per unit area. And "heat rate per unit area" describes things in much more understandable way than incorrectly used "heat flux".
What's more, we all know we cannot use just watts, "heat flux" or other single parameter to compare different builds.

Things really get messed up when someone actually understands all this stuff

Laws doin' what laws do, this is all really pretty basic stuff if one understands the laws of thermodynamics.
So to simplify, with a given coil temp. and AFR, what coil design will produce the desired result?

 

[Hans Wermhat]

My head hurts. Y'all stop brain'n already!!!! Lol!

 

[GoBlue88]

Higher resistance equals lower drain rates on your battery.

Can anyone else confirm this? This seems to be counterintuitive, but my electrical physics is lousy, as evidenced by this thread.