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Ohm's & Wattage setting

Todoboffin

Member For 4 Years
Member For 3 Years
Member For 2 Years
Is there a building chart or something that shows the best watts for a certain ohm build? Like say whats the best watts for a .2 build, or .3, and so on.
 

suprtrkr

Bronze Contributor
Member For 3 Years
Member For 2 Years
ECF Refugee
It's really more about heat flux at the coil surface. If you build a .5 ohm coil out of 24ga wire and another out of 28ga, the 24 will take more watts to heat up in the dame amount of time, and to attain the same surface temp. Go to Steam Engine and, on the coil building page, you'll see heat flux (mW/mm^2) over in the block to the right. Play with the wattage adjustment and you can see how the surface temp moves up and down.
 

robot zombie

Silver Contributor
Member For 4 Years
When it comes to setting your wattage, it's not about the ohms. Say I do two builds with a resistance of .2. The first is a dual 24g, while the other is a single 24g. The single will need 25% as much power as the dual because it has a quarter of the mass, even though they both read at the same resistance.

It's much more practical to get into the habit of choosing power levels based on the mass of your builds. All that the resistance determines is how the wattage is attained... ...it determines how much of your power is current and how much is voltage. For you, this is meaningless. It's just something for the device to worry about. Watts are watts. The key thing to work out is how many of them you need per unit of mass. You can work it out, but it's often easier to just experiment with your wattage until you find a good balance.

If you read anything past this, read the last two little paragraphs.

Now, if you want to somewhat work it out, here is what you will need to know...

Like suprtrkr said, let heat flux be your guide. Heat flux is basically how much heat energy is being transferred at any given time. It marks the flow of heat energy through the coil. Most people set their wattage according to the heat flux. However, there's more to it than that and doing this will not always get you the results you expect. While flux ultimately shows how much heat energy will be generated, it isn't the only factor in determining how hot your coil will get. "Heat energy" and "temperature" are not the same. A high flux doesn't necessarily mean a hot coil. Flux only reflects the heat energy transfer potential at x wattage.

That's where your heat capacity comes in. It shows how much heat energy it takes to raise the temperature of the whole mass of the coil by 1 degree kelvin - in other words, it denotes ramp-up time. If heat flux is a measure of how much heat energy travels at a given wattage, then heat capacity is how much heat energy it takes to bring the overall temperature up.

If your build has a high heat capacity, then you will want to increase the wattage so that it heats up in a reasonable amount of time. You can shoot for a higher flux, as it will require more heat energy to raise the temperature at a sufficient rate. Even though heat energy is traveling through the coil faster (high flux,) it has more mass to disperse across (high capacity,) so it needs a greater overall flow of heat energy.

If the heat capacity is lower, then you may also want to have a lower flux, as the temperature of the coil will increase more readily. Even though less heat energy is being pushed through, less is needed to heat the coil to x temperature in y amount of time. Since flow of heat energy doesn't have as much mass to disperse across, the build will quickly overheat if there's too much heat energy moving through it.

It's really a combination of the two. You have to balance your heat flux and thus your wattage to your heat capacity.

Think of the coil as a bucket of water. You have a hose pouring water into it at a fixed rate. That's your heat flux... ...it's how fast water is pouring into the bucket. The size of the bucket is your heat capacity. Now, let's say you have a big bucket and a small bucket, both with separate hoses going into them. You want them both to fill up at the same time. The bigger bucket (high capacity) will need more water flowing from the hose (high flux,) while the smaller bucket (low capacity) will require less water flowing from the hose (low flux.)

Basically, a high-capacity coil will not be as hot as a low-capacity one at a given wattage. Even if you adjust wattage to give them the same flux, the low-capacity build will still get hotter faster. Or at least, that's my understanding of the two properties.


But like I said initially, it's not really necessary to know this stuff. Don't sweat it if this doesn't make any sense. It helps if you understand it, both for determining what builds to do and how to power them, but at the end of the day, you still have to dial it in, as other factors such as wicking efficiency, airflow, chamber size, and even coil diameter all affect heating. Looking at the numbers can only give you an idea. A very good one in a relative sense, but still far from a complete picture.

Hopefully, this all explains why there is no chart such as the one you're looking for. The best wattage for any given build is subjective and depends on many different variables.

Look at the size of your coil and take a guess at how much wattage it needs to run in the atty you're using. Then, run below that estimate and work your way up. Trial and error.
 
Last edited:

Neunerball

Platinum Contributor
Member For 4 Years
Member For 3 Years
ECF Refugee
Actually, there is a chart. However, it's totally outdated, due to improved mods, and replacement coil heads.
image.jpeg
 

Todoboffin

Member For 4 Years
Member For 3 Years
Member For 2 Years
When it comes to setting your wattage, it's not about the ohms. Say I do two builds with a resistance of .2. The first is a dual 24g, while the other is a single 24g. The single will need half as much power as the dual because it has half of the mass, even though they both read at the same resistance.

It's much more practical to get into the habit of choosing power levels based on the mass of your builds. All that the resistance determines is how the wattage is attained... ...it determines how much of your power is current and how much is voltage. For you, this is meaningless. It's just something for the device to worry about. Watts are watts. The key thing to work out is how many of them you need per unit of mass. You can work it out, but it's often easier to just experiment with your wattage until you find a good balance.

If you read anything past this, read the last two little paragraphs.

Now, if you want to somewhat work it out, here is what you will need to know...

Like suprtrkr said, let heat flux be your guide. Heat flux is basically how much heat energy is being transferred at any given time. It marks the flow of heat energy through the coil. Most people set their wattage according to the heat flux. However, there's more to it than that and doing this will not always get you the results you expect. While flux ultimately shows how much heat energy will be generated, it isn't the only factor in determining how hot your coil will get. "Heat energy" and "temperature" are not the same. A high flux doesn't necessarily mean a hot coil. Flux only reflects the heat energy transfer potential at x wattage.

That's where your heat capacity comes in. It shows how much heat energy it takes to raise the temperature of the whole mass of the coil by 1 degree kelvin - in other words, it denotes ramp-up time. If heat flux is a measure of how much heat energy travels at a given wattage, then heat capacity is how much heat energy it takes to bring the overall temperature up.

If your build has a high heat capacity, then you will want to increase the wattage so that it heats up in a reasonable amount of time. You can shoot for a higher flux, as it will require more heat energy to raise the temperature at a sufficient rate. Even though heat energy is traveling through the coil faster (high flux,) it has more mass to disperse across (high capacity,) so it needs a greater overall flow of heat energy.

If the heat capacity is lower, then you may also want to have a lower flux, as the temperature of the coil will increase more readily. Even though less heat energy is being pushed through, less is needed to heat the coil to x temperature in y amount of time. Since flow of heat energy doesn't have as much mass to disperse across, the build will quickly overheat if there's too much heat energy moving through it.

It's really a combination of the two. You have to balance your heat flux and thus your wattage to your heat capacity.

Think of the coil as a bucket of water. You have a hose pouring water into it at a fixed rate. That's your heat flux... ...it's how fast water is pouring into the bucket. The size of the bucket is your heat capacity. Now, let's say you have a big bucket and a small bucket, both with separate hoses going into them. You want them both to fill up at the same time. The bigger bucket (high capacity) will need more water flowing from the hose (high flux,) while the smaller bucket (low capacity) will require less water flowing from the hose (low flux.)

Basically, a high-capacity coil will not be as hot as a low-capacity one at a given wattage. Even if you adjust wattage to give them the same flux, the low-capacity build will still get hotter faster. Or at least, that's my understanding of the two properties.


But like I said initially, it's not really necessary to know this stuff. Don't sweat it if this doesn't make any sense. It helps if you understand it, both for determining what builds to do and how to power them, but at the end of the day, you still have to dial it in, as other factors such as wicking efficiency, airflow, chamber size, and even coil diameter all affect heating. Looking at the numbers can only give you an idea. A very good one in a relative sense, but still far from a complete picture.

Hopefully, this all explains why there is no chart such as the one you're looking for. The best wattage for any given build is subjective and depends on many different variables.

Look at the size of your coil and take a guess at how much wattage it needs to run in the atty you're using. Then, run below that estimate and work your way up. Trial and error.

Wow.... I hope you make a lot of money at your job. LOL
 

robot zombie

Silver Contributor
Member For 4 Years
Wow.... I hope you make a lot of money at your job. LOL
Bahaha, not even, though I'm told I'm very good at what I do for a living. I rake-in a living wage from a normal, boring 9-5. I don't love it, but then, I am not my job, so it's fine by me. Part of coping with not making the money you want and not doing the work you want is having things that immerse you outside of work. Life isn't just about how much money you make, but how much satisfaction you have in your day-to-day. As with many other things that I do outside of work, I write posts here for leisure and funsies ;) Vaping has been a very stimulating hobby for me, so there's no effort involved in thinking and rambling about it in as much detail as I can muster. It's harder not to, sometimes, heh.

I know Nuenerball thinks I'm too verbose (and I don't disagree!) I'm just surprised he didn't call me out on it this time lol.

For real though, I hope it helped shed some light on things for you or at least got you wondering and augmented your thinking. I know I have a tendency to over-complicate simple matters sometimes. suprtrkr really said all that needed to be said.
 

JERUS

Gold Contributor
Member For 4 Years
Member For 3 Years
Member For 2 Years
Member For 1 Year
Bahaha, not even, though I'm told I'm very good at what I do for a living. I rake-in a living wage from a normal, boring 9-5. I don't love it, but then, I am not my job, so it's fine by me. Part of coping with not making the money you want and not doing the work you want is having things that immerse you outside of work. Life isn't just about how much money you make, but how much satisfaction you have in your day-to-day. As with many other things that I do outside of work, I write posts here for leisure and funsies ;) Vaping has been a very stimulating hobby for me, so there's no effort involved in thinking and rambling about it in as much detail as I can muster. It's harder not to, sometimes, heh.

I know Nuenerball thinks I'm too verbose (and I don't disagree!) I'm just surprised he didn't call me out on it this time lol.

For real though, I hope it helped shed some light on things for you or at least got you wondering and augmented your thinking. I know I have a tendency to over-complicate simple matters sometimes. suprtrkr really said all that needed to be said.
I like to think I'm pretty educated on this stuff, but it helped clear some things up for me about heating. My research comes from spurts of motivation and necessity mainly and considering I can just take a low educated guess and work up I've never needed to learn all that much about it, but nice to have a bit more understanding.
 
Last edited:

MWorthington

Silver Contributor
Member For 4 Years
ECF Refugee
When it comes to setting your wattage, it's not about the ohms. Say I do two builds with a resistance of .2. The first is a dual 24g, while the other is a single 24g. The single will need 25% as much power as the dual because it has a quarter of the mass, even though they both read at the same resistance.

It's much more practical to get into the habit of choosing power levels based on the mass of your builds. All that the resistance determines is how the wattage is attained... ...it determines how much of your power is current and how much is voltage. For you, this is meaningless. It's just something for the device to worry about. Watts are watts. The key thing to work out is how many of them you need per unit of mass. You can work it out, but it's often easier to just experiment with your wattage until you find a good balance.

If you read anything past this, read the last two little paragraphs.

Now, if you want to somewhat work it out, here is what you will need to know...

Like suprtrkr said, let heat flux be your guide. Heat flux is basically how much heat energy is being transferred at any given time. It marks the flow of heat energy through the coil. Most people set their wattage according to the heat flux. However, there's more to it than that and doing this will not always get you the results you expect. While flux ultimately shows how much heat energy will be generated, it isn't the only factor in determining how hot your coil will get. "Heat energy" and "temperature" are not the same. A high flux doesn't necessarily mean a hot coil. Flux only reflects the heat energy transfer potential at x wattage.

That's where your heat capacity comes in. It shows how much heat energy it takes to raise the temperature of the whole mass of the coil by 1 degree kelvin - in other words, it denotes ramp-up time. If heat flux is a measure of how much heat energy travels at a given wattage, then heat capacity is how much heat energy it takes to bring the overall temperature up.

If your build has a high heat capacity, then you will want to increase the wattage so that it heats up in a reasonable amount of time. You can shoot for a higher flux, as it will require more heat energy to raise the temperature at a sufficient rate. Even though heat energy is traveling through the coil faster (high flux,) it has more mass to disperse across (high capacity,) so it needs a greater overall flow of heat energy.

If the heat capacity is lower, then you may also want to have a lower flux, as the temperature of the coil will increase more readily. Even though less heat energy is being pushed through, less is needed to heat the coil to x temperature in y amount of time. Since flow of heat energy doesn't have as much mass to disperse across, the build will quickly overheat if there's too much heat energy moving through it.

It's really a combination of the two. You have to balance your heat flux and thus your wattage to your heat capacity.

Think of the coil as a bucket of water. You have a hose pouring water into it at a fixed rate. That's your heat flux... ...it's how fast water is pouring into the bucket. The size of the bucket is your heat capacity. Now, let's say you have a big bucket and a small bucket, both with separate hoses going into them. You want them both to fill up at the same time. The bigger bucket (high capacity) will need more water flowing from the hose (high flux,) while the smaller bucket (low capacity) will require less water flowing from the hose (low flux.)

Basically, a high-capacity coil will not be as hot as a low-capacity one at a given wattage. Even if you adjust wattage to give them the same flux, the low-capacity build will still get hotter faster. Or at least, that's my understanding of the two properties.


But like I said initially, it's not really necessary to know this stuff. Don't sweat it if this doesn't make any sense. It helps if you understand it, both for determining what builds to do and how to power them, but at the end of the day, you still have to dial it in, as other factors such as wicking efficiency, airflow, chamber size, and even coil diameter all affect heating. Looking at the numbers can only give you an idea. A very good one in a relative sense, but still far from a complete picture.

Hopefully, this all explains why there is no chart such as the one you're looking for. The best wattage for any given build is subjective and depends on many different variables.

Look at the size of your coil and take a guess at how much wattage it needs to run in the atty you're using. Then, run below that estimate and work your way up. Trial and error.

I realize this is an old post, but it is freakin' excellent!!:)
 

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