Coils and Power: Theory and Practice

[blueGrassTubb]

I'm wondering how the mechanics of using wattage on multiple coils works. Bear with the scenario a minute. It's not all based in fact, but that's because I'm interested in both the theoretical framework (the math) and how the theory translates in real world use.

I know that I can vape XΩ at Y watts comfortably. It's a nice vape, that one. I've been using it for a few months on a regulated MOD, but I'm interested in using an atty where I can wrap 2 coils instead of the one that I have in my Igo-L. I know that with my XΩ coil in the Igo-L and my APV set at Y watts the MOD is pushing Z volts.

Theoretically if I were to now wrap a dual coil setup AT THE SAME RESISTANCE (XΩ), exactly half the voltage from the battery will go to one coil with the other half going to the second coil (assuming that each coil is exactly the same). So now instead of Z volts going to one coil, there is Z/2 volts going to each coil by virtue of both coils sharing the positive.

Should I now theoretically be able to pump up the wattage to Y * 2 watts, bringing the voltage to each coil up to the same level as the single coil was receiving from the battery and get more or less double the amount of vapor in the same amount of time? Or am I just going to burn the hell out of my juice?

In short, how much higher can I pump up a regulated MOD when I use a dual coil of the same resistance as a single coil I've been using.

Thanks.

 

[gandalas]

I can tell you my own anecdotal experience just from the past week (and my first foray into dual coils on my Kayfun Lite).

I was used to running single coils in the .7 to 1.4 range, and it seemed that no matter what, I could not push it much above 8 Watts on my 7-22 mod, or I would start getting that burnt taste from my cotton.

Well, I built my dual micro-coil a couple of days ago, measuring in at .8 ohms of resistance from the dual coils, and I am not getting much of an enjoyable experience under the 14-15 Watt range with that build.

So theoretically from my own limited experience, it does indeed seem that you double the wattage going out for double the coils and the same quality of vape.

As far as liquid consumption goes, I have not noticed TOO much of a difference...now battery life on the other hand? Significantly reduced.

 

[blueGrassTubb]

I can tell you my own anecdotal experience just from the past week (and my first foray into dual coils on my Kayfun Lite).

I was used to running single coils in the .7 to 1.4 range, and it seemed that no matter what, I could not push it much above 8 Watts on my 7-22 mod, or I would start getting that burnt taste from my cotton.

Well, I built my dual micro-coil a couple of days ago, measuring in at .8 ohms of resistance from the dual coils, and I am not getting much of an enjoyable experience under the 14-15 Watt range with that build.

So theoretically from my own limited experience, it does indeed seem that you double the wattage going out for double the coils and the same quality of vape.

As far as liquid consumption goes, I have not noticed TOO much of a difference...now battery life on the other hand? Significantly reduced.

It's weird that you can't run above 8W with a .7Ω-1.4Ω. I run 1.4Ω at 15W and 1.5Ω at 14W. I run a 1.7Ω at 12.5W.

Thanks for the anecdote.

 

[gandalas]

It's weird that you can't run above 8W with a .7Ω-1.4Ω. I run 1.4Ω at 15W and 1.5Ω at 14W. I run a 1.7Ω at 12.5W.

Thanks for the anecdote.

Blame my horrific coil building, I suppose?

 

[EDO]

My experience is you double the watts but the vape from a dual coil is actually smoother. You get more vapor and flavor and creamier vape with the dual coil. The vapor is significantly more but it is not double.

I don't get your experience that you vape at lower watts with higher ohms unless your using different gauge wire to achieve the higher resistance. I am going to give an extreme example but....if you make a coil using 28g wire and achieve a 1 ohm coil and then you make another coil with the 28g wire but with double the wraps at 2ohms....are you saying you would actually vape the 2 ohm coil at lower watts? My experience is that the more mass in the coil the more wattage you need to push the coil. I would vape the 2 ohm coil about double the wattage of the 1 ohm coil.....this is assuming that wicking and airflow were not a problem. It is the same way with dual coils....you have the doubled the mass of coil by doing a dual coil setup so you need to vape it at about the double the wattage of the single coil. Another way of thinking about it is you have two coils that are 1.5ohms one is made with 32g wire and the other with 28g wire....I would vape the 32g coil at about 11 watts while I would vape the 28g wire at about 25 watts....they are the same ohms but the 28g coil is way more massive and needs a lot of wattage to push it. Again the only way that what your saying makes sense if you are using different gauge wires to achieve the higher resistance.....but then you really can't compare coils using ohms when they are made of different gauge wires.

 

[drmarble]

The voltage (push) in a dual coil isn't split evenly between each coil. It is the same as for a single coil (assuming a perfect battery or constant voltage). The negative side of the coil is at ground and the positive is at V+ (4 volts, say). The aperage (currrent flow) is divided evenly between each coil. If you run constant volts (or use an ideal mech) the total current through two identical parallel coils would be twice the current through one coil as each was seeing the same voltage. Thus, the power in each coil would equal the power in you single coil dripper (V=I*R). So, if you are running constant watts you would want to set it to twice the wattage of a single coil.
I could explain this better. Maybe I will try again later.

 

[daviedog]

Learn Joule law. P=V•I.
Formulas for multiple resistance points are not additive.
Simple divided voltage I=V divided by RI+R2. Lots more of this in your studies!
2 coils will create 2 magnetic fields with resulting flux interactions. Stand off to posts will introduce variances in resistance. More difficult to predict voltage drops with any reliance.
Oh yeah, do you think you can produce 2 identical coils? By hand? If so why do manufacturers invest 5 figures for machines to do it.
Don't get me wrong, I try too. I just don't expect miracles & when one does, I don't question it. I vape it..

 

[drmarble]

For some reason, I cannot edit the above post.
Think of an ideal battery, or a mod set to constant voltage V and a bunch of coils with resistance R. If you hook up one coil it will have a current of I=V/R and a power of P=V*V/R. If you put a coil next to it it will have the same current I+V/R and the same power P=V*V/R. It acts as though the other coil wasn't there; it just sees the voltage V. The total power in this situation would be 2P, 1P from each coil. So, when you go from your IGO-L to a dual coil setup with identical coils, you should double the power on your mod. You could also just use constant voltage settings and keep them the same.
For example. If you like a 2 ohm coil at 8 watts you are running at 4 volts whether you know it or not P=8watts=4V*4V/2ohms. If you stick another 2 ohm coil in next to it and want it to act the same just run it at the same 4 volts. Each coil will have the same current as the single coil. The power will double. So, you could just set the mod to 16 watts when you run a double coil.
Other factors like air flow, wicking and heat transfer make this less exact in real life but the theory is a good starting point.
I just wish I could edit that error filled post I made above.

 

[drmarble]

Duplicate post.

 

[blueGrassTubb]

Thank you gentleman (ladies?).

I tend to conflate current (amperage) and voltage.

In an ideal world I would have better explained my example. I do know that current and voltage are different, but in explanation I tend to meld thm in to one, hence my errors in the original post.

Voltage stays the same, current is what gets cut in half when you add a second coil necessitating the doubling of power so that each coil will receive the same current.

Got it.

Thank you very much.

 

[slappy3139]

Thank you gentleman (ladies?).

I tend to conflate current (amperage) and voltage.

In an ideal world I would have better explained my example. I do know that current and voltage are different, but in explanation I tend to meld thm in to one, hence my errors in the original post.

Voltage stays the same, current is what gets cut in half when you add a second coil necessitating the doubling of power so that each coil will receive the same current.

Got it.

Thank you very much.

Assuming both coils are the same resistance, the current is doubled and the total resistance of the circuit is halved, and the wattage doubles. The only way your scenario happens is if you are adding a coil in a series circuit, which is not the case, these coils are in a parallel circuit.

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