LR atty vs HV atty: Surface area and Watts?

[Stinky Uncle Ed]

I'm trying to figure out which atty is better, a low resistance atty or a high voltage atty. It would seem to me that the high voltage atty would offer a much longer coil (with a lot more surface area) to achieve the higher resistance, and thus be a juice hog that produces much more vapor, and that the whole aiming for 7 watts does not really apply. Maybe on a high voltage mod, if you use a variable voltage device to decrease the voltage by a bit, and keep the atty wet, it will produce much more vapor than a standard or low resistance atty and not necessarily have the burnt taste people complain of? Since driving attys at currents above 2 amps or more is what seems to shorten their life, then isn't it a factor of current, not watts that determines the heat of the coil and how warm the vapor will be?

Shouldn’t the whole concept of different resistance attys be similar to how if you designed an incandescent light bulb to work at higher voltages at the same current draw, you would only increase the length of the filament, and thus the lumen output would increase proportionally to the length of the filament and increase in voltage?

Here is an MS paint picture I made. I know these aren't common battery voltages to use, but just imagine a 3 volt battery to the LR atty, and three 3 volt batteries to the high voltage mod.

I can’t seem to find an answer so I appreciate any feedback, especially if anyone has taken apart a LR and HV atty from the same manufacturer and compared the coils.

 

[Dalton63841]

To my knowledge the coil on high voltage atties is not always longer(although it probably is), but thicker, which is why HV atomizers can withstand alot more heat.

 

[Sedateme]

Your line of thinking is how it was explained to me when I asked a similar question. Take 2 setups, each putting out similar wattage. 3.7V at 1.7ohm, and 5v at 3.1 ohms. The first puts out 8.05 watts, the second puts out 8.06 watts. I asked what the difference would be, or if both would be the same. It was explained that the 1.7 ohm setup has less surface area, so it does get much hotter at a given wattage. The 3.1 ohm setup is either thicker, or has a longer coil, thereby giving it more surface area, and doesn't need to get as hot to attain the same wattage.

Is one better than the other? Some people like a hotter vape... others not so much. The extra heat from a low resistance coil might trash your favorite juice, or make it the best vaping experience you've seen so far. Totally depends on the juice, and user preference.

 

[Dalton63841]

Nice to see a thread putting to rest this myth that Equal Watts = Equal Vape that I see spouted around here so much.

 

[Stinky Uncle Ed]

To my knowledge the coil on high voltage atties is not always longer(although it probably is), but thicker, which is why HV atomizers can withstand alot more heat.

But being thicker would reduce its resistance, so not only would it have to be longer normaly to achieve a higher resistance, but now it has to be much, much longer to also make up for the loss of resistance by the thicker coil...

Your line of thinking is how it was explained to me when I asked a similar question. Take 2 setups, each putting out similar wattage. 3.7V at 1.7ohm, and 5v at 3.1 ohms. The first puts out 8.05 watts, the second puts out 8.06 watts. I asked what the difference would be, or if both would be the same. It was explained that the 1.7 ohm setup has less surface area, so it does get much hotter at a given wattage. The 3.1 ohm setup is either thicker, or has a longer coil, thereby giving it more surface area, and doesn't need to get as hot to attain the same wattage.

In your example the 1.7 Ohm atty at 3.7 Volts would be drawing a current of 2.17 Amps, and your 3.1 Ohm atty at 5.0 Volts would be drawing a current of 1.61 Amps. I'm figuring that atties are kind of like a fuse in that they get hotter as a function of increasing current until they pop, so I woulden't say the second one is not is not as hot because it has a larger coil and more surface area, but it's not as hot because it's running at a lower current.

I'm starting to think watts don't mean anything in terms of the heat of the coil and the vapor, since a higher resistance atty will always require more voltage to overcome the extra resistance of a longer coil to meet a desired current, and therefore allways consume much more wattage. I think the extra watts are distributed along a longer, larger coil so the whole thought process of OMG it's over 12 watts or what-not is irrelevant because you now have a much larger heating element that will produce much more vapor at a given current than a smaller, lower resistance coil at the same current.

Thanks for your replies, both of you! Any more feedback anybody else has is welcome.

 

[unloaded]

The length or diameter of the wire used for coil aren't the only things that could change the resistance. A different alloy could be used to get higher resistance with the same physical characteristics. Just muddying up the water a bit more 8)

 

[Sedateme]

I think Uncle Ed has some good points. Using wattage to describe a "sweet spot" is misleading, but a very common practice here. To me, it all comes down to personal preference anyway. Even if wattage was an accurate indicator of how a juice would vape, how a juice tastes is a personal matter anyways. What works for me may or may not work for anyone else.

What had originally piqued my curiosity about the whole wattage situation, was seeing people say "this is good, but its awesome at higher voltages." It's a pretty logical thing to assume you can get a higher voltage vape experience by using lower resistance atomizers/cartomizers, but that isn't 100% accurate and Uncle Ed has just stumbled on why it isn't.

So I've got a nice variable voltage device in my hot little hands, but my batteries haven't arrived. No lcd display, just a knob that I can turn and dial in to where my juice tastes good. This will work for me

 

[Stinky Uncle Ed]

The length or diameter of the wire used for coil aren't the only things that could change the resistance. A different alloy could be used to get higher resistance with the same physical characteristics. Just muddying up the water a bit more 8)

I don't like that idea. So that just ends up being a coil that doesn't land you with any extra surface area or length, and just ends up burning hotter; and burning juice

I think I like the idea of high resistance achieved by a long coil with large surface area that doesn't burn exceptionally hot and can vape lots of juice quickly due to it's high surface area. I wonder if anyone has any ideas of a HV 510 with a very large coil?

 

[markfm]

Keeping it simple is a good thing

LR at standard/lower voltages "simulates" the experience of higher voltages/resistance, but isn't precisely the same, which is one reason to try a cheap intro to HV -- a true dumb passthrough plus 2A USB power supply, about $25 total. Try it with a 3 ohm atty/carto

 

[Stinky Uncle Ed]

I think Uncle Ed has some good points. Using wattage to describe a "sweet spot" is misleading, but a very common practice here. To me, it all comes down to personal preference anyway. Even if wattage was an accurate indicator of how a juice would vape, how a juice tastes is a personal matter anyways. What works for me may or may not work for anyone else.

What had originally piqued my curiosity about the whole wattage situation, was seeing people say "this is good, but its awesome at higher voltages." It's a pretty logical thing to assume you can get a higher voltage vape experience by using lower resistance atomizers/cartomizers, but that isn't 100% accurate and Uncle Ed has just stumbled on why it isn't.

So I've got a nice variable voltage device in my hot little hands, but my batteries haven't arrived. No lcd display, just a knob that I can turn and dial in to where my juice tastes good. This will work for me

Thanks man. Well put.

I can't wait to get my first variable voltage device. I'm guessing the best vaping experience would be using a HV atty with a lot of surface area, which you can still flow an obscene amount of voltage (and therefore current) too, and get the coil burning very hot for a good throat hit, or dial back the voltage to retain the flavor, while still having a lot of vapor production due to the (Hopefully) high length/surface area of the coil?

 

[unloaded]

I wasn't suggesting going that route just pointing out another variable that gives some wiggle room to this statement:

"But being thicker would reduce its resistance, so not only would it have to be longer normaly to achieve a higher resistance, but now it has to be much, much longer to also make up for the loss of resistance by the thicker coil..."

If there were an ideal length and wire diameter, the wanted resistance could be had by using a different alloy. It's just another piece of the puzzle.

 

[mwa102464]

But being thicker would reduce its resistance, so not only would it have to be longer normaly to achieve a higher resistance, but now it has to be much, much longer to also make up for the loss of resistance by the thicker coil...



In your example the 1.7 Ohm atty at 3.7 Volts would be drawing a current of 2.17 Amps, and your 3.1 Ohm atty at 5.0 Volts would be drawing a current of 1.61 Amps. I'm figuring that atties are kind of like a fuse in that they get hotter as a function of increasing current until they pop, so I woulden't say the second one is not is not as hot because it has a larger coil and more surface area, but it's not as hot because it's running at a lower current.

I'm starting to think watts don't mean anything in terms of the heat of the coil and the vapor, since a higher resistance atty will always require more voltage to overcome the extra resistance of a longer coil to meet a desired current, and therefore allways consume much more wattage. I think the extra watts are distributed along a longer, larger coil so the whole thought process of OMG it's over 12 watts or what-not is irrelevant because you now have a much larger heating element that will produce much more vapor at a given current than a smaller, lower resistance coil at the same current.

Thanks for your replies, both of you! Any more feedback anybody else has is welcome.

Using the same Atty,, Run a standard pv at 3.7v then run a Darwin and up the Watts and I can assure you that you will change your mind on your statement above ! increasing the Watts absolutely increases Heat to the coil and produces more vapor. Just my experience with the Darwin

 

[Stinky Uncle Ed]

Pushing more watts to an atty will increase it's heat, thats for sure!

What I was trying to say though, is that making a blanket statement like "the higher the wattage, the higher the heat" is not necessarily true. Like take post 3 for example, even though they both use ~8 watts, the LR atty gets hotter than the standard atty. What I'm thinking is the HV atties will require the most wattage to be comparable in heat with standard and low resistance atties, but have the added benefit of more surface area for more vapor production, or higher resistance coil matterial which allows the atty to achieve higher temperatures than what is possible with lower resistance ones.

 

[Rocketman]

If they both use 8 watts of electricity that is dissipated as 8 watts of heat, the heater with the smallest surface area MAY get hotter, but total heat will be the SAME.
Coil to coil thermal coupling may contribute to temperature of a heater coil, but 8 watts is 8 watts.
Fluid coupling to the heater hopefully modifies the thermal properties enough to keep the heater from getting "too hot".

How well a carto transfers that heat to generate vapor (which carries some of the heat watts away) is what we are actually experiencing. The watts of heat left behind heats up the carto.

 

[mwa102464]

If they both use 8 watts of electricity that is dissipated as 8 watts of heat, the heater with the smallest surface area MAY get hotter, but total heat will be the SAME.
Coil to coil thermal coupling may contribute to temperature of a heater coil, but 8 watts is 8 watts.
Fluid coupling to the heater hopefully modifies the thermal properties enough to keep the heater from getting "too hot".

I'm not so sure I agree with this statement, pushing say 5.9W @ 1.7A I would think a 1.5ohm Atty will get hotter faster then a 4.5ohm Atty at the same 5.9W @ 1.7A. When I try this on my Darwin the LR will glow orange much quicker then the HV Atty does and looks like it is getting much hotter,, so ?

 

[Rocketman]

How fast it heats (hopefully it doesn't glow when you vape) is a function a thermal mass of the heater and coupling (at the same power level).

What we want is to transfer the watts to the liquid, make vapor and suck the watts out.

 

[Stinky Uncle Ed]

If they both use 8 watts of electricity that is dissipated as 8 watts of heat, the heater with the smallest surface area MAY get hotter, but total heat will be the SAME.

I'm not sure I follow. Not all 8 watts are converted directly into heat are they? I would think that the more overdriven an atomizer is, the more efficient it becomes, where if you drive it at too low a wattage, it stops even heating up and starts to behave just like a conductor wire.

I have a little background in building flashlights for instance, and know that some incandescent bulbs will put out ~20 lumens per watt when a bulb is driven to spec, but as you overdrive them with much higher voltage (and thus higher current and wattage) their efficiency increases to ~50 lumens per watt. I'm not sure if lumens and heat scale up at a 1:1 ratio though in this case.

But this example would lead you to believe that higher watts must equal higher total heat production, which I don't know is truly the case. I think 5 watts put through a LR atty would produce more total heat than 5 watts through a HV atty if both were measured in a closed system for heat production but perhaps I'm wrong.

 

[Rocketman]

The overdriven lamp output shifts spectrum (less heat per watt input). The watts of electricity input will equal the watts of something output. It has to go somewhere. Except for the glowing carto heater, the output is in the infrared end of the spectrum. The heater heats up the carto some, the carto heats the connector, the connector heats the mod, but the rest goes to heating the fluid and vaporizing it (except for some strange endothermic reaction taking place we don't want to know about ). Hot vapor carries some of the watts with it. The rest of the watts stay behind.

You are correct about ultimate temperature and the rapid change in temperature. But isn't all of this just to get some watts down our throats?

Vapers have chased the "sweet spot" by increasing voltage applied to a given atty/carto. Then we started seeing lower resistance products to keep the market from dying for the 3.7 volt stuff.

Different atty designs, different resistances, different voltages, different wattages, which is the best combination?

Using dual coil (and now triple coil) cartos makes it even more confusing. Twice the heaters, twice the watts, half the resistance. What is the difference in vapor produced by a 1.6 ohm dual coil as compared to a 1.6 ohm single coil carto? Which one consumes more watts (at the same voltage)?
At a low voltage the two 3.2 ohm coils may not individually get hot enough to vaporize enough liquid to produce enough vapor where as a single coil does. Still the same amount of total heat generated, but the two coil are cooler in this case.

Confusing? Yup, and it gets worse the more you think about it (especially late at night).

Watts in, watts out, watts left behind.
That's my story, and I'm sticking to it


Uncle Ed:
Please don't think that I'm trying to argue.
That is not my intent.

 

[Stinky Uncle Ed]

Thanks for the insightful replies Rocketman. This is quite a bit to digest, but exactly the type of information I am looking for!

Funny you should mention dual and tripple coil cartos, I actually just bought a 1.5 Ohm dual coil 510 atomizer from clouds of vapor, and am running through the math as we speak, I just know for certain that it will provide the type of surface area that a regular HV 510 atty won't be able to.

 

[Dalton63841]

Thanks for the insightful replies Rocketman. This is quite a bit to digest, but exactly the type of information I am looking for!

Funny you should mention dual and tripple coil cartos, I actually just bought a 1.5 Ohm dual coil 510 atomizer from clouds of vapor, and am running through the math as we speak, I just know for certain that it will provide the type of surface area that a regular HV 510 atty won't be able to.

Dual coils are a whole different monster, and confuse many. For instance, a 1.5ohm dual coil, is technically 2x 3ohm coils, which is why even though they are labelled as LR, they can go up to 6v easily.