I'd like a definitive answer once and for all: do amps matter?

[Maurice Pudlo]

This is pedantry.

Absolutely. I'm a pretty black and white kind of thinker, especially when it comes to really interesting conversations like this.

coils can be "rewired" below the deck in an appropriate atomizer without touching the coils at all...

I imagine so.

...if that helps you visualize.

Not really. If we negate leg length and set it at zero there remains a difference between series and parallel coils. I will absolutely grant you that this difference is not likely something anyone would notice, they are 98.3% similar and that 1.6ish % difference is very small.

Maurice

 

[dr g]

Absolutely. I'm a pretty black and white kind of thinker, especially when it comes to really interesting conversations like this.



I imagine so.



Not really. If we negate leg length and set it at zero there remains a difference between series and parallel coils. I will absolutely grant you that this difference is not likely something anyone would notice, they are 98.3% similar and that 1.6ish % difference is very small.

Maurice

More importantly, the question isn't whether it is the same or not, but why it is the same or not. Is it the amperage/resistance numbers, or the physical characteristics of the build? It's entirely the latter.

 

[AzPlumber]

Ok I'll look it over.

Maurice

Edit: close, very close, but to get identical mW/mm^2 results between 3 1ohm coils in series vs the same 3 in parallel you have to mess with the leg length a tiny bit 0.1mm to be exact.

Diameter: 1.3mm
Leg Length: 5mm
AWG: 22 kanthal a1

Series outputs 59mW/mm^2 at 3ohms (1ohm per coil)
Parallel outputs 60mW/mm^2 at 0.333ohms (1ohm per coil)

For all intense and purposes I can see how the two would vape nearly the same.

Maurice

Instead of adjusting anything just add a hand full of three's to your parallel setup and see if that doesn't get you there.

 

[Maurice Pudlo]

More importantly, the question isn't whether it is the same or not, but why it is the same or not. Is it the amperage/resistance numbers, or the physical characteristics of the build? It's entirely the latter.

Right it is the build, so long as there is no modulation to the power delivery.

In the first example the setup of .25 ohms @ 4 volts results in 64 watts and 16 amps

In the second example the setup of 3 ohms @ 13.85 volts results in 64 watts and 4.6618 amps
(13.85641 to be exact, just in case anyone's feeling particularly .... lol)

How many builds can be postulated that would output a similar vape experience between the sets of numbers provided above by the OP vs how many would result in different vape experiences?

Maurice

 

[Maurice Pudlo]

Instead of adjusting anything just add a hand full of three's to your parallel setup and see if that doesn't get you there.

Or ignore the fact that a 0.99 ohm coil isn't exactly a 1.0 ohm coil, right.
http://www.steam-engine.org/coil.asp?s=tp&r=0.33&hfnw=27&awg=22&ll=0
http://www.steam-engine.org/coil.asp?s=tp&r=0.333&hfnw=27&awg=22&ll=0

MP

 

[dr g]

How many builds can be postulated that would output a similar vape experience between the sets of numbers provided above by the OP vs how many would result in different vape experiences?

Maurice

This is irrelevant to the question of whether amps per se cause a difference in vape. Even if there were no possible build that would be equal, the difference in vape would be caused by the build and not the amperage/resistance.

 

[AzPlumber]

Or ignore the fact that a 0.99 ohm coil isn't exactly a 1.0 ohm coil, right.
Coil wrapping | Steam Engine | free vaping calculators
Coil wrapping | Steam Engine | free vaping calculators

MP

Not sure where a .99 ohm coil was discussed.

What I did point out is your results are not accurate due to the limitation of three decimal places representing the resistance value of three 1 ohm coils in parallel.

 

[rurwin]

Not sure where a .99 ohm coil was discussed.

What I did point out is your results are not accurate due to the limitation of three decimal places representing the resistance value of three 1 ohm coils in parallel.

I don't think that will explain the error. Resistance is linearly related to power. He's got a 2% error in power and a 0.03% error in resistance.

I'm certain enough of the maths to say that I think there is a software bug involved, or at least different assumptions between the serial and parallel cases.

 

[rurwin]

How many builds can be postulated that would output a similar vape experience between the sets of numbers provided above by the OP vs how many would result in different vape experiences?
Maurice

I can turn that argument on its head. See this series build that takes 3 amps? How many parallel builds are there that result in a different vape vs the single unique case that does. See? -- Voltage control is pointless.

Of course the build makes a huge difference. It always does, for every coil we make. And with currently available atttys, building series coils is not easy. There are ways and means, but to build a series and parallel pair that were comparable would be challenging. However that is not the point.

Current is important, at least as important as voltage. I could make a good argument that VA was more useful than VV. The fact that we can make two mirror-image builds is merely an exercise that proves the two have the same capabilities. The question was posed in the OP for that reason.

The real point of VA is that once you build one coil with a given type of wire then, given that the wicking is mostly comparable, every coil you build with that wire, no matter what the size and shape of the coil, no matter how much wire it uses, will behave similarly if fed the same current. Of course it won't be perfect, the build matters, but it will be at least as close as VW ever is, and better in most cases.

In comparison, VV has no such claims except that it can drive multiple coils in parallel as if they were one, and then the build makes so much difference that there is not much point.

 

[dr g]

Current is important, at least as important as voltage. I could make a good argument that VA was more useful than VV. The fact that we can make two mirror-image builds is merely an exercise that proves the two have the same capabilities. The question was posed in the OP for that reason.

The real point of VA is that once you build one coil with a given type of wire then, given that the wicking is mostly comparable, every coil you build with that wire, no matter what the size and shape of the coil, no matter how much wire it uses, will behave similarly if fed the same current. Of course it won't be perfect, the build matters, but it will be at least as close as VW ever is, and better in most cases.

In comparison, VV has no such claims except that it can drive multiple coils in parallel as if they were one, and then the build makes so much difference that there is not much point.

I'm not one to pooh-pooh new ideas or applications of technology, but I'd have to say that VA would be nearly pointless due to the requirement of wicking and airflow to scale with the coil. There's no quick, easy and objective way to do that so expecting to scale up a coil, use VA, and get the same result but more of it is ... perhaps a bit of an oversimplification. In the end it seems no better than VV to me.

 

[rurwin]

In the end it seems no better than VV to me.

It seems no better than VW to me. While VW is doubtless useful to be able to switch between a 1.8ohm Kanger head and a 2.2 ohm Kanger head, nobody would claim that a 5-turn 1 ohm coil would vape the same as a 10-turn 2 ohm coil at the same power. In that case the power used for one might be a useful starting point for the other, but no more.

Similarly, one might replace a 5-turn microcoil by winding 6 turns on a slightly different former, and expect the same current to work. If the differences between the builds were more extensive, then the originally used current would be only an indication of where to start looking.

It has the potential to be better than VW where the differences between builds are down to the length of wire used. VW fails in this case, whereas VA handles it. When coils are different sizes, wicking also changes and this may counteract any advantages VA has. But it may be practicable to make two coils of different sizes with similarly efficient wicking. If one can build a long coil and a short coil, where the wicking produced the same liquid feed per length of coil, then VA would have a clear advantage over VW. There is no evidence, either way, whether this is practicable. It may be that experienced coil builders do this as a matter of course. A well-built wick may always produce the right liquid density per length. It is at least worth some experimentation.

 

[TheRac25]

In the first example the setup of .25 ohms @ 4 volts results in 64 watts and 16 amps
In the second example the setup of 3 ohms @ 13.85 volts results in 64 watts and 4.6618 amps
(13.85641 to be exact, just in case anyone's feeling particularly .... lol)

The difference comes down to the amp draw on the battery

maybe its been covered already but the amp draw on the battery by the boost converter in the second setup will exceed 16 amps

 

[dr g]

maybe its been covered already but the amp draw on the battery by the boost converter in the second setup will exceed 16 amps

covered in post #6

It seems no better than VW to me.

 

[Dampmaskin]

I don't think that will explain the error. Resistance is linearly related to power. He's got a 2% error in power and a 0.03% error in resistance.

I'm certain enough of the maths to say that I think there is a software bug involved, or at least different assumptions between the serial and parallel cases.

It's a rounding (GIGO) error. Change 0.33 to 0.333, and watch 0.99 turn to 1. I just tried it.

 

[tj99959]

So the only person who doubts that amps matter is the OP, and everyone who answered said they did. What is the problem?

Amps, volts and resistance make an inter-related triad. Change one and the others have to change to compensate. Any two define the third and any two define the power. The power together with the mechanical details -- coil configuration, wicking, airflow -- and the electrical details -- series, parallel or a combination -- define the vape qualities.

Current is important, but altering the current does not necessarily change the vape quality. It usually will, but it can be arranged not to. It requires two variables to define power, and current by itself does not do so. Just as vaping cannot happen without current, it cannot happen without resistance and voltage. If you have current without resistance, then nothing will get hot enough to make vapour. Changing the current changes the voltage and power unless the resistance also changes, just as changing the voltage changes the current and power unless the resistance changes. If the resistance changes, then the vape quality will also change because the mechanical details -- the coil size -- change. So on its face, changing either voltage or current will change the vape quality, either because the power changes, or because the coil dimensions change.

This is the situation that we all know -- changing any one factor changes the vape. Current and voltage are both exactly as important as each other. If we want to change the vape, it doesn't matter which one we control, either one will change the other. They are exactly symmetric. But they are the inverse of each other. We can put coils in parallel and keep the voltage constant, or we can put coils in series and keep the current constant. One coil will always vape differently than two coils, but we can build two coils in either parallel or series and keep the power the same. Other factors being equal, two coils producing the same power will behave the same, and it doesn't matter if we do it by keeping the voltage constant and increasing the current or by keeping the current constant and increasing the voltage.

Glad to see that we FINALLY convinced you.

 

[rurwin]

Glad to see that we FINALLY convinced you.

I haven't changed my opinion. I've just found a form of words that expresses our agreement in terms that you accept.

 

[rurwin]

You said "In the end it seems no better than VV to me."
VV really has no advantages in normal vaping. It is used because it was first.

On the other hand, VA does have advantages, similar in scope to those of VW. I therefore re-worded your quote: "It seems no better than VW to me."

In fact, I believe that in certain circumstances, and with a following wind, it may be better than VW ... for some definition of the word "better".