Dual coil confusion

[neohaven]

You haven't read my post, have you? I'm trying to explain to you why and how, when you combine 2 resistances, you halve their resistance. It's because you need to supply twice the current, so from the point of view of the battery the resistance has halved.

I'm showing you how to derive the information on that page. Also, that page is not a counter-argument to what I have written. It is in perfect agreement with the last paragraph. It just goes the other way around. It divides the amps of the circuit into n different resistors. I combine the amps of the resistors instead.

Solving a circuit like this works both ways.

For your convenience, let me re-explain the last paragraph of my post :

Each resistor does not care that it is in parallel. Being in a complex circuit or alone does not change the nature of a resistor, as long as we are pushing DC current in it. Ohm's law applies to it. The "parallel" and the "series" rules are derived from exactly this. At the "HERE" in the circuit, if we put an ammeter in series and a voltmeter in parallel, we'll see 4.2V and 4.2A. From Ohm's Law, we have R=V/A, Thus an equivalent resistance of 1Ohm. This is exactly how the parallel circuit law works.

Seriously, 2*2Ohm coils *will* be a 1Ohm draw on your batt, and *will* pull 4.2A on a fresh mech battery for example.

 

[neohaven]

You are, of course, absolutely correct, but the OP was asking about a 2 ohm single coil vs. a 2 ohm dual coil, not putting two 2-ohm coils in parallel.

Yep, but here :

Running a single 2 ohm coil at say 4 V, you are making 8 watts. Typically a pretty good vape.

Run two 2 ohm coils at 4 V you are also making 8 watts, but the power is split between the coils, so each coil is seeing only 4 watts. A very cool vape from each coil!

This is plain wrong. 2x2 Ohm coils in parallel will be equivalent to a 1 Ohm coil. At 4V, it will pull 4A, which is 16W. Each coil will see 8 watts, as if it wasn't in a parallel circuit. There will be twice the drain. If he had 2x4Ohm coils, equivalent resistance 2 Ohm, *then* he would be right. It would be 4 Watts per coil.

 

[Ryedan]

You haven't read my post, have you? I'm trying to explain to you why and how, when you combine 2 resistances, you halve their resistance. It's because you need to supply twice the current, so from the point of view of the battery the resistance has halved.

I'm showing you how to derive the information on that page. Also, that page is not a counter-argument to what I have written. It is in perfect agreement with the last paragraph. It just goes the other way around. It divides the amps of the circuit into n different resistors. I combine the amps of the resistors instead.

Solving a circuit like this works both ways.

For your convenience, let me re-explain the last paragraph of my post :

Each resistor does not care that it is in parallel. Being in a complex circuit or alone does not change the nature of a resistor, as long as we are pushing DC current in it. Ohm's law applies to it. The "parallel" and the "series" rules are derived from exactly this. At the "HERE" in the circuit, if we put an ammeter in series and a voltmeter in parallel, we'll see 4.2V and 4.2A. From Ohm's Law, we have R=V/A, Thus an equivalent resistance of 1Ohm. This is exactly how the parallel circuit law works.

Seriously, 2*2Ohm coils *will* be a 1Ohm draw on your batt, and *will* pull 4.2A on a fresh mech battery for example.

I did read your post neohaven, I just didn't get it. You are correct. I got it wrong starting in my first post when I compared the 2 ohm dual coil in the OP's post to two 2 ohm coils. The DiscountVapers data convinced me I had it right

Thanks for the correction!

 

[wv2win]

I'm going to go against the flow here.

Running a single 2 ohm coil at say 4 V, you are making 8 watts. Typically a pretty good vape.

Run two 2 ohm coils at 4 V you are also making 8 watts, but the power is split between the coils, so each coil is seeing only 4 watts. A very cool vape from each coil!

To get the full potential from the dual coils you would need to increase the voltage to about 5.7 V to have 16 watts split between the coils. Or you would need to reduce each coils resistance back to 2 ohms making the dual coil resistance 1 ohm, which would also increase total power to 16 watts. This gives each coil 8 watts and the vape becomes the best it can be.

Check out the Discountvapers website here. Scroll down almost to the bottom to where they discuss dual coil cartos.

I agree completely. Using a 3.0 ohm single coil carto I will set the watts at around 8 - 8.5 watts. With a 1.5 ohm dual coil I increase the watts to around 11 - 12 watts.

 

[Ryedan]

I agree completely. Using a 3.0 ohm single coil carto I will set the watts at around 8 - 8.5 watts. With a 1.5 ohm dual coil I increase the watts to around 11 - 12 watts.

Yup, watts need to go up, but in a VV device you don't have to increase the voltage. The amp draw will take care of it if the device can supply it. That's what I got wrong in my post.

 

[K_Tech]

Random, but my coil just went down .1 ohms out of nowhere. What?

Something shorted... time to take a close look at what's going on with your coil.

 

[UncleChuck]

Though the voltage and resistance stays the same the amperage is Higher which will drain batteries faster

This is totally false.

Amperage is determined BY voltage and resistance. If resistance and voltage are the same, it's impossible by the known laws of physics for the amperage to change. The only way to increase amperage is to increase voltage and/or decrease resistance.

To the OP,

The setting you want depends on your own personal preference. But in nearly every case, commercially produced dualcoils of the same resistance will be able to handle a lot more voltage compared to a single coil of the same resistance. The reason for this is clear when you look at how a dualcoil setup works.

If you have a dualcoil setup with an overall resistance of 2ohm (which means your multimeter or PV's ohm checker will show 2ohm) that means there are two coils, each one being 4ohm.

With a single coil 2 ohm setup, you obviously have one coil at 2 ohms.

Say you are running at 4volts. The dualcoil will be like running two separate PVs at 4 watts each, because each coil is putting out 4 watts, and there are two coils.

The singlecoil will be putting out 8 watts (double the power) on the same coil. Because the power is concentrated on a single coil, instead of spread over two, it will heat up faster, and get hotter. The dualcoil will be much cooler and heat up slower, because each coil isn't getting nearly as hot.

So if you run a dualcoil of the same resistance, you can (and generally need to) increase your voltage by a bit to account for this. The plus side is that you have far more headroom, and can increase your voltage higher before burning, because the power is spread out over two coils instead of one.