Comment from ECF (Electronic Cigarette Forum): SmokTech Dual Coil Cartomizer

I've tried them all: every cartomizer and atomizer made. Every manufacturer, and even the "cisco" versions and 20 or so other websites trying to get attys and cartos made to a special design.

Nothing compares to these dual coils from smoktech. End of story.

510 thread: win

Size: About the size of everyones "Mega" cartomizers. Like the Iken megas and also the other smoktech megas. Hold around 2 mil of juice if you take your time filling. I condom fill them from the top and then the bottom to get rockin fast.

1.5 ohm: They WILL NOT BURN. How you can slam 6 volts into a 1.5 ohm and it not insta nuke or at least burn the juice, I have no idea. I melted a delrin drip tip trying to see if I could burn juice. It gets hot, sure, but the juice just turns to magma with no "burnt plastic" taste coming from the polyfill. Darwin says I'm hammering 4.5 volts into this thing and pulling almost 3 amps !!! No burn taste. 

Vapor Production: UNREAL. You dont need pure VG and long drags anymore for that fancy vape cloud for you video anymore. I can fog a room with an ego bat now, lol. My GGTS is actually used now because I don't even need my VVs. Sure it rocks on the Darwin and Provari, but I'm not forced into using them. I actually cut back my normal 60/40 pg/vg to 80/20 because I was developing a smoker's cough again from so much vapor.

Useability: Gravy, easy as it gets. You can drip fill them, condom fill them, syringe fill them: whatever you want. I just drip them after an initial condom fill. 10 drops tops me off. I have to work for a living, and don't have time to constantly refill. I don't want to carry syringes like a ...... addict, I like to just top them off. They hold the juice well, and don't flood. Darwin is absolute fail in respect to no catch cup, so we can't use leaky attys or cartos or flood prone ones. Don't have to worry about leaking with these, and they do quite well.

Lifespan: Same as most the other quality cartos out there. I vape over 6ml a day, and I'm getting about 4 days out of one. I could go farther I'm sure, but vapor slowly drops off and the draw gets tighter. Cleaning might be an option, but at these prices, I just chunk them. After a month of using these, I've retired about 8 of them. Wifey has gone through 3 but she vapes a whole lot less then I do. Brother has gone through 5. NONE of them were DOA, and none shorted. No matter how much voltage we hit them with. Supplier will love these because they wont have to warranty any more cartos cause someone redlined them with some stack bat mod.

Availability: TONS of people are stocking these now. Why? Because they are godly. I ordered 5 to test from madvapes, they rocked. Then I got in a freebie 5 from Nhaler with my darwin order because they sold something they did not have at the time. Then I placed my order from China for 200 of them because I wanted Chrome. Ordered 40 more from hoosier to tide me over till china got here. All of them perform fantastic, no matter where I got them from.

Here is some nice math and explenations from Madvapes new newsletter. Really excellent! None of this is my work, just copied and pasted from their newsletter. Feel free to email them and thank them!

Dual Coil cartomizer is the latest craze to the vaping world. There are a number of factors as to why they work so well and we will break them down. The first thing about them is that as the name implies, there are two coils or heating elements in them which is why they produce so much vapor. Below is a dual coil cartomizer and each of its components. It really is a simple circuit. Coil 1 connects directly to the positive terminal of the connector in the middle. There is a wire (the long one) that connects the positive terminal of the connector to Coil 2 so both coils are getting identical voltages from the circuit as opposed to splitting the voltage as would be the case with a circuit in series. The two coils then meet in the middle and are connected to the negative terminal of the connector via the smaller wire completing the circuit.

As a rule the lower the resistance the more power there is going to the coil making it hotter and producing more vapor. While the overall resistance of a dual coil cartomizer is about 1.6 ohms, it is a circuit with the coils in parallel so each coil individually has 3.2 ohms of resistance. Lets see how this relates using Ohm’s Law. Below is a diagram of a basic Parallel circuit. R 1 and R 2 would represent the coils in the cartomizer.

Ohm’s Law –

I = V/R Amperage = Voltage / Resistance

Full voltage is applied to both resistances within the circuit. Resistance is determined by:

R = V/I

In a parallel circuit the formula is:

R 0 represents total resistance. R 1 and R 2 are the 2 different coils in the cartomizer. So the resistance for a dual cartomizer would be

R 0 = 3.2 x 3.2 / 3.2 + 3.2

= 10.24 / 6.4

= 1.6 ohms

So the circuit of a dual coil cartomizer with two 3.2 ohm resistance coils has a total resistance of 1.6 ohms. What does this mean. It means you get a low resistance cartomizer that still works with higher voltages because the individual coils are working at 3.2 ohms.

Now lets compare the amperage of a cartomizer versus a dual coil cartomizer. (I = V / R)

Single Coil

I = V / R

= 3.7 / 3.2

= 1.16 amps

Amperage of a Dual Coil Cartomizer can be done 2 ways.

I 0 = I 1 + I 2

This would be the equivalent of calculating the amperage of each coil separately and then adding them together. So in the above formula 2 coils with like resistance would be:

I 0 = I 1 + I 2

=1.16 + 1.16

= 2.32 amps

The other way is with the formula:

I 0 = V / R 0

I 0 is the total amperage of the circuit and R 0 is the total resistance of the circuit.

I 0 = V / R 0

= 3.7 / 1.6

= 2.31 amps (Rounding accounts for the small difference)

The other comparison we can have is with power which is measured in watts.

W = V * I

W = V * (V / R) is another way of stating it.

So a single coil would be:

W = V * (V / R)

= 3.7 * (3.7 / 3.2)

= 3.7 * (1.16)

= 4.28 watts

A dual coil could be calculated by adding the wattage of each coil together like was done with amperage. Or you could just use the resistance of the total circuit like below.

W = V * (V / R 0 )

= 3.7 * (3.7 / 1.6)

= 3.7 * (2.3)

= 8.56 watts (as you can see it is exactly double the single coil figure)

So a dual coil cartomizer gives you twice the watts (power) and twice the vapor. If you use a cartomizer with too low of a resistance quite often it will damage the cartomizer because there is too much power for it to be able to handle it. But because each coil is actually running at 3.2 ohms of resistance a 3.7 or 5 volt source works just fine. If you go to higher voltages such as 7.4 volts the biggest problem is the protected circuit of the batteries. They often detect a short with such low resistances and the protected circuit is tripped. But if you had a battery with a protected circuit that could handle that low of a resistance, the cartomizers appear to work just fine without hurting the cartomizer or burning the e-liquid.  

If you want to read more please visit here  http://www.e-cigarette-forum.com/forum/cartomizers/177866-smoktech-dual-coil-cartomizers.html