A basic understanding of resistance/Ohms and how it relates to building coils and vaping?

[gordian]

I'm taking my first step later today when my kanthal and iTaste MVP 2 arrive and venturing into the world of rebuildables with my lovely IGO-L. I took physics throughout high school and university but that was ages ago and there is so much info out there that it's tough to wade through to get a simple understanding of the forces at work. I'm confident in my ability to work with my hands, but I'd like some feedback on whether I've got a good basic understanding of the principles behind what I'll be doing later today and how it applies to vaping.

Since the iTaste has VV and VW the only "fixed" variable in my vaping setup after my coil gets built will be resistance. The resistance of my kanthal coil increases with length, so I can either wrap a small diameter coil many times, or a larger diameter coil a few times and end up with nearly equivalent resistance/Ohms (but the vape could be different due to surface area). Correct?

My practical understanding is that lower resistance will enable me to keep my voltage lower to obtain a warmer vape (temperature determined by Amps?) and not wreak havoc on my battery (I = V/R). Correct?

By increasing the resistance of my coil, I'd need to increase voltage in order to maintain the same vape temperature (Amps). This can drain my battery much quicker. Correct?

All I have to go on are my current vaping habits on my eGo Spinner and Vivi Novas, so it seems I'm best off calculating my Watts/Amps from my current setup and creating a lower resistance setup to replicate the Amps I currently vape at. Correct?

Again, I suspect this info is probably out there but with so many guides and resources it's a bit of information overload and I'd really appreciate any feedback or comments indicating whether my understanding is correct or completely cookoo.

Thanks!

 

[AaronY]

-----------ignore--------

 

[xpen]

(deleted, please see post from Rader here below)

 

[finagle69]

Actually heat is determined by Power in Watts. 2.5 Amps @ 6 Volts will give you the same "warmth" of vape as 3.75 Amps @ 4 Volts. Both of those are 15 Watts.

Different diameter coils with equal resistance (and same wire gauge) will have ~the same surface area, As resistance is a function of wire length.

If your goal is to get less battery drain, make higher resistance coils and apply higher voltage. Low ohms and lower voltage may give you the exact same power (warmth), but the current will be much higher.

I'm an EE. PM me if you want further help.

 

[gordian]

Thanks for the info guys!

In typical USPS fashion my mail came the latest it possibly could and I'm going to wait until I'm better rested tomorrow to tackle my first build with fresh eyes.

Will definitely post results and hopefully some coil porn!

 

[shoggot]

As a side note, it sounds like you're going to be running on an APV - most (perhaps all?) have a lower bound for ohmage, below which they will not fire. Typically around 1.5 ohms or so, so you'll want to aim for that or somewhat higher.

 

[Rader2146]

...
Battery drain is due to Ampere load, the higher it is the shorter the battery run time will be.. You can achieve the same Watts by means of either (relatively) low res/low voltage or high res/high voltage: in the first case, the A drain will be higher - easily twice as much - and hence the battery runtime will be shorter.

...

Actually heat is determined by Power in Watts. 2.5 Amps @ 6 Volts will give you the same "warmth" of vape as 3.75 Amps @ 4 Volts. Both of those are 15 Watts.

Different diameter coils with equal resistance (and same wire gauge) will have ~the same surface area, As resistance is a function of wire length.

If your goal is to get less battery drain, make higher resistance coils and apply higher voltage. Low ohms and lower voltage may give you the exact same power (warmth), but the current will be much higher.

I'm an EE. PM me if you want further help.

With a VV or VW device, resistance will have no effect on battery drain current. Conservation of energy...
Battery Life - Low Resistance, High Resistance, and Efficiency.

 

[xpen]

With a VV or VW device, resistance will have no effect on battery drain current. Conservation of energy...
Battery Life - Low Resistance, High Resistance, and Efficiency.

Oops, I always forget that with regulated mods there are TWO sides to keep in mind.. Can't really argue with any of that, great explanation thank you.

So I infer provaris must give their best efficiency with higher loads/voltages.. While for instance the DNA20 always saps the battery (more or less) regardless of atom resistance. (considerations out of practical experience)

No clues about the mod of the original poster, though..

 

[WattWick]

Actually heat is determined by Power in Watts. 2.5 Amps @ 6 Volts will give you the same "warmth" of vape as 3.75 Amps @ 4 Volts. Both of those are 15 Watts.

Different diameter coils with equal resistance (and same wire gauge) will have ~the same surface area, As resistance is a function of wire length.

If your goal is to get less battery drain, make higher resistance coils and apply higher voltage. Low ohms and lower voltage may give you the exact same power (warmth), but the current will be much higher.

I'm an EE. PM me if you want further help.

Problem with that is that different surface area equals different wire gauge. Thus equalling different resistance over the same surface area. Besides stacking batteries, or "wasting" capacity on boosting voltage from a single-cell battery, you really have no way of adjusting wattage. This is the reason some people use mechanical mods, coil their coils for a certain wattage, and swap batteries once they drop below a certain level of vapor production.

There is only so much one can do with either a buck boost circuit or a selection of resistance wires at varying gauges. The make-up of those resistance wires remain the same. There are only a handful different alloys used for our purposes. So, what sets one coil apart from another is mainly gauge and length... and heat sinking effect from different wick materials.

 

[finagle69]

Problem with that is that different surface area equals different wire gauge. Thus equalling different resistance over the same surface area. Besides stacking batteries, or "wasting" capacity on boosting voltage from a single-cell battery, you really have no way of adjusting wattage. This is the reason some people use mechanical mods, coil their coils for a certain wattage, and swap batteries once they drop below a certain level of vapor production.

There is only so much one can do with either a buck boost circuit or a selection of resistance wires at varying gauges. The make-up of those resistance wires remain the same. There are only a handful different alloys used for our purposes. So, what sets one coil apart from another is mainly gauge and length... and heat sinking effect from different wick materials.

Which is why I put the caveat of same wire gauge.

Sent from my HTC One using Tapatalk