Coil wire coefficients

[Walt]

I realize this is information that is not necessary for vaping, but it's just bugging me.

I have one tank that has an element which offers .5 ohms of resistance and it vaporizes my favorite juice @ 32 watts dissipated. Another tank is at 1.5 ohms and does a similar job at 9 watts. Watts = I2R. Current through a coil produces heat. The current in the first tank should produce much greater heat than the second.

What am I missing? Different coil metals used with different coefficients of heat per current conducted?

I'm confused. It seems as if a sub ohm coil should require much less wattage to produce the same heat as a coil greater than an ohm.

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[FXRich]

14 hours ago, Walt said:

 

I realize this is information that is not necessary for vaping, but it's just bugging me.

I have one tank that has an element which offers .5 ohms of resistance and it vaporizes my favorite juice @ 32 watts dissipated. Another tank is at 1.5 ohms and does a similar job at 9 watts. Watts = I2R. Current through a coil produces heat. The current in the first tank should produce much greater heat than the second.

What am I missing? Different coil metals used with different coefficients of heat per current conducted?

I'm confused. It seems as if a sub ohm coil should require much less wattage to produce the same heat as a coil greater than an ohm.

Sent from my iPad using The Vapor Talk mobile app

 

Your .5 coil is made of wire that is a heavier gauge than the 1.5 coil, so there is more metal to heat than the lighter gauge wire, An example would be when welding with a heavier wire you need more amps then with a lighter wire.

I use temperature control most of the time, and it takes more watts to keep the temp at what I want when using a heavier gauge metal than with a lighter gauge wire.

I'm not very good at explaining things so I might have confused you even more.

[FXRich]

Another way to look at is a 1.5 ohm coil at 9W runs 3.7V, a .5 coil at 32W runs 4V, so a .5 coil will run 2.1V at 9W which probably isn't enough to get it hot very fast.

Not much difference between 3.7V and 4V.

[Squid]

Like Rich says above a lower ohm coil will produce more heat at a set voltage than a higher ohm coil. Watts are not constant across a range of resistances as they are a product, I think, of the relationship between resistance (Ohms) and voltage. It has to do with Ohm's Law. I get the basics of, but don't understand Ohm's Law well enough to explain it. All I can recommend to get it explained is to look up Ohm's Law on the net or wait for someone here that can actually explain it.

My guess as to why we set watts on our mods is that it is actually a finer adjustment than volts.

[Adversarious1]

On 12/24/2016 at 6:56 PM, Walt said:

 

I realize this is information that is not necessary for vaping, but it's just bugging me.

I have one tank that has an element which offers .5 ohms of resistance and it vaporizes my favorite juice @ 32 watts dissipated. Another tank is at 1.5 ohms and does a similar job at 9 watts. Watts = I2R. Current through a coil produces heat. The current in the first tank should produce much greater heat than the second.

What am I missing? Different coil metals used with different coefficients of heat per current conducted?

I'm confused. It seems as if a sub ohm coil should require much less wattage to produce the same heat as a coil greater than an ohm.

Sent from my iPad using The Vapor Talk mobile app

 

Late to chime in on this, but one of the least confusing ways to think about it that I have come across is the water pipe analogy.  In this analogy you need think of the following:

Say you have two pipes, one of them a .5 inch pipe and the other is a 1.5 inch pipe.  Now say you have 100 gallons of water and you want to push 50 gallons of water through each pipe in exactly the same amount of time.  For sake of argument, we'll say that amount of time is 10 seconds.  With the smaller diameter of the .5 inch pipe it is going to take a lot more pressure to get the water through that pipe than it would through the 1.5 inch pipe.  The same principle applies to coils.  The .5 ohm coil requires a higher wattage to reach the same temperature than the 1.5 ohm coil.

That is a very basic analogy and there is much more to it, but the main point of the analogy is to explain why a coil of a lower rating requires more power to function in a similar manner as a coil of a higher rating.

[Walt]

@Adversarious1 Thank you for chiming in on this.  I think I better admit I'm an EE by education, although that was back in the stone age of mostly tubes.  I get the electrical physics but I was having difficulty wrapping my head around the heat production capabilities of different wire compounds.  After reading a sit load of technical articles on this, I was able to grasp the difference in surface areas and heat dissipation of the different wire structures.  I was not considering that it was the resistance itself that was causing the friction to develop the heat.  Daaaaa.   In the day, heat was the problem and avoiding it was key to something that would last over a day. This is the first application that I have worked with that purposely uses low resistance wire to produce heat.  Now I get it.  It isn't only heat intensity that is important, it is overall BTU at controlled temperatures.  Love the technology!!!