Volt/Watt/Amp???

[ckn71nm]

Everywhere on this forum I read about volts and watts when it comes to how people use there mods. It is my understanding that this is actually not the important part of what is creating the vapor. That would be current going through the coil meaning Amps combined with surface area of the coil.

Just a rough calculation:
2.5 Ohm @ 15 W = 2.4 Amps
1.8 Ohm @ 15 W = 2.8 Amps
0.8 Ohm @ 15 W = 4.3 Amps

or for mechanical mods at 3.7 volt:

2.5 Ohm @ 3.7 V = 1.48 Amps (5 W)
1.8 Ohm @ 3.7 V = 2.1 Amps (7 W)
0.8 Ohm @ 3.7 V = 4.6 Amps (17 W)

That’s why people with a sub ohm micro-coil get so much more vapor than if you would run the same watts/volts on a store bought commercial atty with 1.8 or 2.1 ohm.

My question is: Why aren't there any variable current devices out there? It can’t be that hard to let the users set the amps they want, do the quick P = I^2 x R and run the mod at the resulting watt. Most mods you can buy today have more processing power than my first computer.

 

[JmanEspresso]

Variable Amp mods ehh?

IF it doesn't already exist, I would be someone is working on it. Maybe Evolv has it in the works.

 

[ckn71nm]

Variable Amp mods ehh?

IF it doesn't already exist, I would be someone is working on it. Maybe Evolv has it in the works.

I hope so. The new Futura mod form NexGen, running the Evolv DNA 30 board, claims to have processing power equivalent to a Pentium 100. They should should be able to do that.

 

[rob33]

amps is the result of volt/watt x ohm. amps is what is used from the battery to produce v/w x ohm. exceed amp rating of the battery and it over heats

 

[TheSystemHasFailed]

Well, to simplify it, always remember the constant of that 4.2V (I hope you bring your batts to 4.2) then, just plug in your resistance...the rest are the resulting numbers. Amps and watts. Which are only determined by those first 2 values.

Nice little calculator, I only ever enter 4.2, and whatever resistance I'm running. The Amps and Watts fill them selves out after calculation.

Watts - volts - amps - ohms conversion calculator

Meaning, your Amps are ALSO getting auto adjusted, due to the volts in, at that ohm/resistance of your atty, when you vape.
It's a measure of the first two drawing that much. Don't draw that much power if you want variable amps...it's already there!

 

[Ryedan]

Everywhere on this forum I read about volts and watts when it comes to how people use there mods. It is my understanding that this is actually not the important part of what is creating the vapor. That would be current going through the coil meaning Amps combined with surface area of the coil.

Just a rough calculation:
2.5 Ohm @ 15 W = 2.4 Amps 6.1V
1.8 Ohm @ 15 W = 2.8 Amps 5.2V
0.8 Ohm @ 15 W = 4.3 Amps 3.5V

or for mechanical mods at 3.7 volt:

2.5 Ohm @ 3.7 V = 1.48 Amps (5 W)
1.8 Ohm @ 3.7 V = 2.1 Amps (7 W)
0.8 Ohm @ 3.7 V = 4.6 Amps (17 W)

That’s why people with a sub ohm micro-coil get so much more vapor than if you would run the same watts/volts on a store bought commercial atty with 1.8 or 2.1 ohm.

My question is: Why aren't there any variable current devices out there? It can’t be that hard to let the users set the amps they want, do the quick P = I^2 x R and run the mod at the resulting watt. Most mods you can buy today have more processing power than my first computer.

That's not quite correct ckn71nm. (I added voltage in red to the first set of numbers you listed above to point out that changes also.)

The amount of heat produced by the coil depends on the watts applied to it. Thicker wire has more surface area per watt than thinner wire so it spreads the heat over more area which allows more vapor to be produced without drying out the coil at that power level.

So, in your first set of three examples, the same amount of heat will be produced in each. It is however likely the 2.5 ohm coil is made with thinner wire than the 0.8 ohm coil and will be closer to burning juice at 15 watts than the typical 0.8 ohm coil with thicker wire.

In your second example for mechanical mods, yes of course when you keep the volts stable, power follows amps and either will define the amount of heat delivered to the coil. However, if you solve for identical amps, you see what happens to the power:

2.5 Ohm @ 4.2 V = 1.68 Amps (7.0 W)
1.8 Ohm @ 3.03 V = 1.68 Amps (5.1 W)
0.8 Ohm @ 1.34 V = 1.68 Amps (2.26 W)

The first two are actually possible to vape because you can get both voltages from a li-ion battery, I just wouldn't run down to 3.03V too often . The 7 watts will produce more heat and vapor than the 5.1 watts. And you can see where it goes at 0.8 ohms.

If I got this wrong, someone please correct me.

 

[ckn71nm]

Well, to simplify it, always remember the constant of that 4.2V (I hope you bring your batts to 4.2) then, just plug in your resistance...the rest are the resulting numbers. Amps and watts. Which are only determined by those first 2 values.

Nice little calculator, I only ever enter 4.2, and whatever resistance I'm running. The Amps and Watts fill them selves out after calculation.

Watts - volts - amps - ohms conversion calculator

Meaning, your Amps are ALSO getting auto adjusted, due to the volts in, at that ohm/resistance of your atty, when you vape.
It's a measure of the first two drawing that much. Don't draw that much power if you want variable amps...it's already there!

What I meant by variable current device is that I would like to be able to adjust Amps much like devices right now allow you to adjust watt or volt. more detail in my next post (which I'm currently writing)

 

[ckn71nm]

That's not quite correct ckn71nm. (I added voltage in red to the first set of numbers you listed above to point out that changes also.)

The amount of heat produced by the coil depends on the watts applied to it. Thicker wire has more surface area per watt than thinner wire so it spreads the heat over more area which allows more vapor to be produced without drying out the coil at that power level.

So, in your first set of three examples, the same amount of heat will be produced in each. It is however likely the 2.5 ohm coil is made with thinner wire than the 0.8 ohm coil and will be closer to burning juice at 15 watts than the typical 0.8 ohm coil with thicker wire.

In your second example for mechanical mods, yes of course when you keep the volts stable, power follows amps and either will define the amount of heat delivered to the coil. However, if you solve for identical amps, you see what happens to the power:

2.5 Ohm @ 4.2 V = 1.68 Amps (7.0 W)
1.8 Ohm @ 3.03 V = 1.68 Amps (5.1 W)
0.8 Ohm @ 1.34 V = 1.68 Amps (2.26 W)

The first two are actually possible to vape because you can get both voltages from a li-ion battery, I just wouldn't run down to 3.03V too often . The 7 watts will produce more heat and vapor than the 5.1 watts. And you can see where it goes at 0.8 ohms.

If I got this wrong, someone please correct me.

I have to say, I almost completely disagree with you.You math is correct and everything checks out, but you are assuming that it is the power that generates the heat. From what I can tell (reading on the web, and we know that if its on the web it must be true ) it is the current that cases wire to heat up.

http://electrical.about.com/od/wiringcircuitry/a/circuitoverload.htm

one of many articles about it.

In a nutshell: Our houses houses, cars and such have fuses to protect the wires from overheating and causing fires. Fuses have amp ratings not watt ratings. You are right that changing the power will also change the amp. When we vape we always adjust the power according to the resistance of the coil we are using. At least in my case, when I build a coil with 1.8 or 2 ohm I will vape at a higher power than one I built at 1.3 ohm. That means I get my favorite vape experience as a result of combining ohm and watt/volt and that is the current.

Just go back to the last few builds you did and calculate the amp at which you used them. I bet you will find that regardless of the coil resistance you always adjust the watt to a point where the current is about the same. I'm thinking that it would be a lot easier to just set amp on a mod and be done with it.

Edit: and by "set amp on a mod and be done with it" I mean let the user select the amp he/she wants.

 

[UncleChuck]

I have to say, I almost completely disagree with you.You math is correct and everything checks out, but you are assuming that it is the power that generates the heat. From what I can tell (reading on the web, and we know that if its on the web it must be true ) it is the current that cases wire to heat up.

http://electrical.about.com/od/wiringcircuitry/a/circuitoverload.htm

one of many articles about it.

In a nutshell: Our houses houses, cars and such have fuses to protect the wires from overheating and causing fires. Fuses have amp ratings not watt ratings. You are right that changing the power will also change the amp. When we vape we always adjust the power according to the resistance of the coil we are using. At least in my case, when I build a coil with 1.8 or 2 ohm I will vape at a higher power than one I built at 1.3 ohm. That means I get my favorite vape experience as a result of combining ohm and watt/volt and that is the current.

Just go back to the last few builds you did and calculate the amp at which you used them. I bet you will find that regardless of the coil resistance you always adjust the watt to a point where the current is about the same. I'm thinking that it would be a lot easier to just set amp on a mod and be done with it.

Edit: and by "set amp on a mod and be done with it" I mean let the user select the amp he/she wants.

Amperage is somewhat of a byproduct figure, useful for checking to see if your build is safe to run with a given battery, but it's a terrible way to judge performance or anything else.

Power, or wattage, is what really matters. Although even wattage figures aren't very useful on their own. Coil temperature depends on how much power you are pumping into it AND how much surface area the coil has. Coil temperature affects flavor, but you shouldn't use coil temp the adjust vapor and TH. Juice vaporizes best at a certain temperature, go hotter and you just burn juice, cooler and you aren't vaporizing properly.

Once that coil temp is reached, if you want to adjust vapor you adjust your surface area. But if you increase surface area, you need to increase power as well to maintain the same coil temp. So ideally, with high-power sub-ohm builds, your coil isn't getting any hotter, there is just far more coil there, at the same temp, so you get far more vapor. Like boiling two pots of water instead of one, you get far more water vapor, but the temp doesn't go up.

If you had a variable current mod, since you cannot adjust the resistance of the coil, the device is simply going to adjust voltage. So it's literally just a VV mod, nothing different, only difference is the units or letter put after the number on your settings screen.

In short, I'm afraid your looking down the wrong path. Current figures don't mean what you think they mean, and aren't useful to us much beyond checking safety.

I figure I'll throw in a real world example:

I currently have a 1.5 ohm coil build sitting on top of my Zmax, which I run with dual 18350s at 6v.

That's 24 Watts of power, drawing only 4 amps. It performs like you would imagine 24 watts would perform, tons of good vapor.

I also have a .5 ohm build on one of my mechs, lets use 4v as the voltage value for calculation:

That's 32 watts of power, drawing 8 amps. As you can see my amperage draw has DOUBLED, but the power has only gone up by about 25% I do get more vapor from this build, but that's because of the increase in power, not current.

Subohm builds perform well because they put out obscene amounts of power, not because of their current draw. Using a high voltage/resistance setup, you can get the same obscene power, but with a relatively tiny current draw. If current was the deciding factor in vapor, then high power, high voltage, high resistance setups wouldn't perform well, and they do. Power is what matters, but it's not the only thing.

 

[ckn71nm]

... I also have a .5 ohm build on one of my mechs, lets use 4v as the voltage value for calculation:

That's 32 watts of power, drawing 8 amps. As you can see my amperage draw has DOUBLED, but the power has only gone up by about 25% I do get more vapor from this build, but that's because of the increase in power, not current...

So, both, power and current are higher. How do you know it's the power and not the current that gives you more vapor?

... Subohm builds perform well because they put out obscene amounts of power, not because of their current draw. Using a high voltage/resistance setup, you can get the same obscene power, but with a relatively tiny current draw. If current was the deciding factor in vapor, then high power, high voltage, high resistance setups wouldn't perform well, and they do. Power is what matters, but it's not the only thing...

Same thing here, Both power and current go up. I think it's the increase in current that gives more vapor. Nothing in your post is a convincing argument that it's not.

You are right that high power/voltage high resistance setups perform well. And that's because:

4 Volt / 0.5 ohm = 8 amp
6 Volt / 0.75 ohm = 8 amp
12 Volt / 1.5 ohm = 8 amp

Obliviously 12 V is ludicrous. That's the reason why sub ohm will always have more vapor than 1.5 ohm. You can't get the current you need in a 1.5 ohm coil.

The thing is, if you take ohm and power/volt as your starting point, when power/volt goes up so will amp. When power/volt goes down, so will amp. I don't think there is a mathematical way to prove which one is responsible for the coil heat. Leaves current rated fuses in households to prevent wires from overheating.

Edit: From your post: ".. Using a high voltage/resistance setup, you can get the same obscene power, but with a relatively tiny current draw.. " No, you can't. High voltage combined with high resistance is high current draw. Unless you build something ridiculous like a 5 ohm coil you run at 10 volts. In that case you have 2 amp. But according to your line of thinking that' also only 20 watts.

 

[ckn71nm]

Oh, I forgot. And why do we use amp draw as measure for safety? We are talking battery overheating and failing right? It's the current that causes the battery to heat up, just as it is the current that causes the coil to heat up.

 

[roadie]

I don't understand what this difference of opinion is about. Wattage, the overall power, is one factor that matters. Therefore, since current, or amperage, is a factor of that power, both are correct and both matter in determining vapor production. Am I missing something here?

 

[UncleChuck]

Oh, I forgot. And why do we use amp draw as measure for safety? We are talking battery overheating and failing right? It's the current that causes the battery to heat up, just as it is the current that causes the coil to heat up.

Simple steps in making sure you're vaping safely:

1: Measure resistance of build
2: Calculate current draw (amperage is the unit for current)
3: Compare to amp rating of battery, and make sure you draw less than the rating.

That' s why amp draw is a measure for safety, because you need to make sure your build is not drawing more current than the battery is rated for.

I don't understand what this difference of opinion is about. Wattage, the overall power, is one factor that matters. Therefore, since current, or amperage, is a factor of that power, both are correct and both matter in determining vapor production. Am I missing something here?

I believe you are missing something.

Current is not a measure of power. I can achieve the EXACT same power levels (wattage) but have different amperage. Amperage means nothing about the build that is useful for our purposes. Higher or lower amp draw does not have to mean higher or lower power.

 

[UncleChuck]

The thing is, if you take ohm and power/volt as your starting point, when power/volt goes up so will amp. When power/volt goes down, so will amp.

That is correct, if you change one of the variables all the others change as well. But current is determined BY voltage and resistance, and it's not a linear relationship. Which means current and power do not raise at lower at the same rate, when comparing the "curve" of vapor production at different power levels, it matches the power curve, not the current curve. That's how you know it's the power making the vapor. Aside from the fact it's called "power" which is understood to mean, well the part that makes the power.

Current is determined BY voltage and resistance
Power is determined BY voltage and resistance.

So, both, power and current are higher. How do you know it's the power and not the current that gives you more vapor?

Because I can (and have) built coils in the past with the same exact power levels, but different amperage, and they vape about the same with most other variables being similar.

The example I used in my last post wasn't a direct comparison because I don't currently have any builds setup that have the same power level with different amperage, but I have in the past.

Consider the following:

Goal: 20 watts of power

You could build a .8 ohm coil on a mech (using 4v for calculations) and get 20 watts. You would be drawing 5 amps.

You could also build a 1.8 ohm coil and run it at 6v on an APV and get 20 watts. You would be drawing 3.3 amps.

In both cases the power levels are identical. They vape similar although differences will arise because you will either use thinner wire, or more wire when compared to the .8 ohm build, so they shouldn't vape identical. But those differences are because of changes in power vs surface area not changes in current.

That's the reason why sub ohm will always have more vapor than 1.5 ohm.

No, it won't. I have a 1.5 ohm coil sitting on my zmax right now that I run at 6v and it blows several of my high-sub ohm builds out of the water in vapor production. Anyone with a good amount of experience rebuilding both low ohm/voltage and high ohm/voltage builds will tell you high resistance can produce just as much vapor as sub ohm. And that's because you can produce just as much power, and that's the important factor in this.



Power ratings tell nothing of resistance and voltage, and current ratings tell nothing of resistance and voltage. Consider a light bulb (for ease of comparison lets use the older bulbs not the new CFLs) it's literally just a coil, nearly identical to an ecig coil. They are rated in watts (power) not current. Your household electricity operates at a fixed voltage, so they COULD rate light bulbs in amps not watts, but they don't, because power (wattage) is the determining factor.

A 60 watt household bulb operating at standard 120v wall voltage will be drawing about HALF an amp. Your lightbulb draws LESS current than your ecig, yet puts out MORE power. That's the relationship between the variables. If current was responsible for vapor, it would also be responsible for light in a bulb, and household light bulbs wouldn't light up the inside of a beaver dam.

Bottom line is that current (amps) is not a reliable measure of vapor production. I can produce the same amount of vapor, at different amperage levels, easily disproving the idea.

 

[roadie]

Simple steps in making sure you're vaping safely:

1: Measure resistance of build
2: Calculate current draw (amperage is the unit for current)
3: Compare to amp rating of battery, and make sure you draw less than the rating.

That' s why amp draw is a measure for safety, because you need to make sure your build is not drawing more current than the battery is rated for.



I believe you are missing something.

Current is not a measure of power. I can achieve the EXACT same power levels (wattage) but have different amperage. Amperage means nothing about the build that is useful for our purposes. Higher or lower amp draw does not mean higher or lower power.

Never said current was a measure of power. I stated it was a factor of power. I 100% disagree with the rest of that post. Amperage determines safety and absolutely is related to power.

Sent from my SGH-T999 using Tapatalk

 

[ckn71nm]

I don't understand what this difference of opinion is about. Wattage, the overall power, is one factor that matters. Therefore, since current, or amperage, is a factor of that power, both are correct and both matter in determining vapor production. Am I missing something here?

I don't think you are missing something. The disagreement is that I'm saying amp is what determines the heat and therefor the vapor and should be adjustable on mods. UncleChuck is saying that the power is what matters and current is not important at all for vapor. Or at least that how I understand it.

... Current is not a measure of power. I can achieve the EXACT same power levels (wattage) but have different amperage. Amperage means nothing about the build that is useful for our purposes. Higher or lower amp draw does not mean higher or lower power.
.

Sorry, but again I have to disagree. Current is the only thing that really matters.

Joule heating - Wikipedia, the free encyclopedia

Quote from ^ "Joule heating, also known as ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor releases heat. The amount of heat released is proportional to the square of the current"

I know, it's Wikipedia, but a very good explanation why the current is responsible for heating, not the power. And we are not disagreeing about safety. I'm with you regarding that all the way.

 

[UncleChuck]

I don't think you are missing something. The disagreement is that I'm saying amp is what determines the heat and therefor the vapor and should be adjustable on mods. UncleChuck is saying that the power is what matters and current is not important at all for vapor. Or at least that how I understand it.



Sorry, but again I have to disagree. Current is the only thing that really matters.

Joule heating - Wikipedia, the free encyclopedia

Quote from ^ "Joule heating, also known as ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor releases heat. The amount of heat released is proportional to the square of the current"

I know, it's Wikipedia, but a very good explanation why the current is responsible for heating, not the power. And we are not disagreeing about safety. I'm with you regarding that all the way.

Feel free to disagree, I think I've made a pretty good argument, which is backed up by real-world hands-on experimentation.

As I said before I can produce the same amount of vapor at different current levels, how does that fit with the theory that current determines vapor? Any guess on why bulbs are rated in watts instead of amps?

Honestly your link about heating being the square of current does make me wonder a bit, I'll have to read a bit more.

Ok upon reading a bit on the wiki, it says heat is not JUST current squared, it's current squared times resistance, which is where the power level makes the determining factor. With low current, you are going to have high resistance, which means a larger number multiplied by the current squared.

As far as I can tell that fits perfectly with what I've been saying.

 

[Ryedan]

So, both, power and current are higher. How do you know it's the power and not the current that gives you more vapor?

I think this is the crux of the confusion here. From Wikipedia:

"In physics, power (symbol: P) is defined as the amount of energy consumed per unit time. In the MKS system, the unit of power is the joule per second (J/s), known as the watt (in honor of James Watt, the eighteenth-century developer of the steam engine). For example, the rate at which a light bulb converts electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit time.[1][2]

Energy transfer can be used to do work, so power is also the rate at which this work is performed. The same amount of work is done when carrying a load up a flight of stairs whether the person carrying it walks or runs, but more power is expended during the running because the work is done in a shorter amount of time. The output power of an electric motor is the product of the torque the motor generates and the angular velocity of its output shaft. The power expended to move a vehicle is the product of the traction force of the wheels and the velocity of the vehicle."

So, watts determine how much heat is created in a coil (light bulb in the example used above). Note I said 'how much' heat, not 'temperature'. Creating that heat is the work being done in this example. As long as the coil is wet, the temperature will be limited to close to the vaporization temperature of the liquid. Think of filling a waxed paper container with water and putting it over a fire to boil the water.

The more heat you pump into the coil, the more juice you can vaporize per second as long as you keep the coil wet. The amount of heat is always directly related to the wattage.

 

[Ryedan]

I don't understand what this difference of opinion is about. Wattage, the overall power, is one factor that matters. Therefore, since current, or amperage, is a factor of that power, both are correct and both matter in determining vapor production. Am I missing something here?

Take it one step further. Watts (power) = volts * amps. When working with a power supply with a constant voltage, if you double the amps (by changing the resistance of the coil) you double the watts. The problem is that when you change both the voltage and the amperage, amps stop having meaning in terms of defining power. Then you have to go to the formula to compare different combinations by using wattage.

Volts define electromotive force . Amps define the flow of electric charges through a conductor (wire in this case).

Watts defines the amount of work done. Higher voltage with lower current can do the same amount of work as lower voltage with higher current.

 

[ckn71nm]

... household light bulbs wouldn't light up the inside of a beaver dam.

I can tell you are getting frustrated. I hope you are not taking it any further with trying to ridicule my arguments instead of making sense.I believe you that you have comparable output of vapor on different coils using same watts, just as much as I have similar vapor on different coils using the same amps.

You could build a .8 ohm coil on a mech (using 4v for calculations) and get 20 watts. You would be drawing 5 amps.

You could also build a 1.8 ohm coil and run it at 6v on an APV and get 20 watts. You would be drawing 3.3 amps.

In both cases the power levels are identical. They vape similar although differences will arise because you will either use thinner wire, or more wire when compared to the .8 ohm build, so they shouldn't vape identical. But those differences are because of changes in power vs surface area not changes in current.

You say you see differences in vapor. And yet the only measurable numbers that change are the amps. The watts are the same.

Household bulbs: Not sure how the difference between AC and DC has an influence on things, but the thing you seem to forget is that one of the main differences between 30 and 60 watt bulbs is the resistance of the filament. And besides changing the power they consume that also changes the current.

I'm not saying that watt has no influence on things. All I'm saying is that in my opinion we change the volt/watt on our mods to adjust the current that flows through the coil. Why not cut out the middle man?