More ohms+less W, less ohms, more W - difference?

[skywinder]

Hello, guys, still can't understand.. According Ohms Law (U=IR, P=IU, => P = I^2*R)

I can build coil with 4 times less resistance and add 2 times more Aps (by increasing wattage on my mod).
So, the Power still the same.

What the difference between these 2 configurations?

 

[Canadian_Vaper]

Surface area.

 

[skywinder]

Surface area.

More ohms, more lenght, more surface area - more flavor, right?

Why Vapers going to reduce ohms then?

 

[Canadian_Vaper]

Look at it this way you can have twice the surface area in half the size but it takes higher amps/lower ohms

 

[IMFire3605]

Most time with lower ohm builds, you use thicker gauge wire, thicker the wire used, takes more time to heat up, thus a 0.5ohm coil using 26awg wire will take longer to heat up compare to a 1.5ohm 32awg coil will due to the mass of the 26awg wire is so much. You can over come this slow ramp up to about equal the heat up of the 32awg by pushing more watts and amps through the 26awg wire, that is why lower ohm and sub-ohm coils take so much power, 8watts on a 32awg 1.8ohm coil is almost instantanious, 8watts on a 26awg 0.5ohm coil would take almost half a minute to have a chance to heat up to proper temp to even boil your e-liquid, but push 30watts at that 0.5ohm 26awg coil, ramp up is about equal to the 32awg 1.8ohm coil, but at that wattage you have to take into account airflow to cool that mass of wire properly. One variable affects the next, and you have to juggle those factors all at once.

 

[Bunnykiller]

less ohms and less voltage = more voltage and more ohms
imagine a seesaw and you put 10 lbs on each end and it balances it out, now put 100 lbs on each end and it still balances out...
the initial reason for low ohm builds was to get higher watts out of battteries when running at nominal voltage, but now that we have VV units we can up the voltage to get more watts instead of dropping the ohms on the coil, but hey!! why not drop the ohms and now we can lower the voltage on the VV unit and have longer battery life...

 

[skywinder]

Most time with lower ohm builds, you use thicker gauge wire, thicker the wire used, takes more time to heat up, thus a 0.5ohm coil using 26awg wire will take longer to heat up compare to a 1.5ohm 32awg coil will due to the mass of the 26awg wire is so much. You can over come this slow ramp up to about equal the heat up of the 32awg by pushing more watts and amps through the 26awg wire, that is why lower ohm and sub-ohm coils take so much power, 8watts on a 32awg 1.8ohm coil is almost instantanious, 8watts on a 26awg 0.5ohm coil would take almost half a minute to have a chance to heat up to proper temp to even boil your e-liquid, but push 30watts at that 0.5ohm 26awg coil, ramp up is about equal to the 32awg 1.8ohm coil, but at that wattage you have to take into account airflow to cool that mass of wire properly. One variable affects the next, and you have to juggle those factors all at once.

Awesome explanation! Thanks!

less ohms and less voltage = more voltage and more ohms
imagine a seesaw and you put 10 lbs on each end and it balances it out, now put 100 lbs on each end and it still balances out...
the initial reason for low ohm builds was to get higher watts out of battteries when running at nominal voltage, but now that we have VV units we can up the voltage to get more watts instead of dropping the ohms on the coil, but hey!! why not drop the ohms and now we can lower the voltage on the VV unit and have longer battery life...

Make sense! So, according this logic - it's better to make as lower ohm as you can, isn't it? (Of course if there enough power to heat up such coil fast and airflow to cool down)

 

[Tol]

Make sense! So, according this logic - it's better to make as lower ohm as you can, isn't it? (Of course if there enough power to heat up such coil fast and airflow to cool down)

It really depends what you are after, it's a balancing act. The best way might be to use the Steam Engine Calculator, you can check out a nice post about using and understanding it HERE
That will help you understand what effects wire size, resists, etc... have on things along with what kind of power you will need to run it all. It also has a nice Ohm's law calc to make sure you keep with in your amperage limits as well.

 

[Grimwald]

Other considerations are.

If your battery is less capable. It is better to use thinner wire. higher ohms so you need lower watts.

If you need longer battery life (ex. long work day) then you would build to use lower watts.

 

[suprtrkr]

There are a lot of tradeoffs. Surface area is one, but the big one, in my experience, is ramp-up time. The wire has to get hot before it makes vapor. Thus, the greater the mass of wire being heated, the longer it takes to get to temp and make vapor if you hold power (watts) the same.

 

[Train2]

great explanations in this thread.
And it's totally a balancing act between surface area, resistance, mass to heat up, airflow, coil temp, and the capability of your mod to provide power.
Then there's preference!
For instance, some folks don't mind a bit of a heat up delay, but it drives me nuts, and I'll sacrifice a little vapor in favor of insta-heat.

 

[suprtrkr]

great explanations in this thread.
And it's totally a balancing act between surface area, resistance, mass to heat up, airflow, coil temp, and the capability of your mod to provide power.
Then there's preference!
For instance, some folks don't mind a bit of a heat up delay, but it drives me nuts, and I'll sacrifice a little vapor in favor of insta-heat.

There it is. Much more art than science. And personal preference plays a big role. One of the things I personally happen to like is twisted wire coils. I don't like them because of the greater surface area-- or maybe I do-- but because they are stiffer than slick wire coils and can be easily re-wicked several times without deforming the coil so you have to recoil the atty. I like Dan Jenkin's famous line about bartending: "measuring whiskey in a hurry ain't nothing but a feeling you acquire..."