So in theory...

[eHuman]

When someone says, "If you can't afford an HV mod, than LR attys which "simulate" HV vaping is your next best option." <This statement would by default presume that HV vaping is the superior option.

But am I correct in assuming that the voltage we vape at is irrelevant? We are just looking for a higher current by using a higher voltage with the same atty?

a. vaping at 6v with a 4Ω atty = 1.5a (1500mA) 9 watts
b. Vaping at 4.5v with a 3Ω atty = 1.5a (1500mA) 6.75 watts
c. Vaping at 3v with a 2Ω atty = 1.5a (1500mA) 4.5 watts

In the example above, a higher voltage source with a "standard" atty would give the same amperage as a lower voltage source with an LR atty but it would consume more power in order to do it.

Are we really just discussing two different methods of achieving the identical desired results? On the surface it looks like the higher voltage mod is just consuming more power to achieve the same results.

Are all three attys in the example expected to last the same amount of time given an identical cycle environment?

Will a single battery/LR atty give a similar VV experience to a double battery/HR atty?

I guess what I'm coming down to is that it would be less expensive to build a a lower voltage device (1/2 the batteries), so is there something I'm not considering that make higher voltage more advantageous?

I can picture how small and robust of a VVV I could make using an LR atty and a 2600mA batt.


ADDED: I should have used this as an example above but no matter:
a. Vaping at 7v with a 3.8Ω atty = 2.33a (2330mA) 16.3 watts
b. Vaping at 5v with a 3.8Ω atty = 1.31a (1310mA) 6.58 watts
c. Vaping at 3v with a 3.8Ω atty = .79a (790mA) 2.37 watts
The wattage increases expotentially as the voltage does linearly. But I think I'm concerned with amps.

 

[AttyPops]

Well, I'm no expert, but since nobody answered yet I'll give it the 1st shot:

It's the POWER (AKA Watts) that counts... your right hand column. Not the amps alone, nor the volts alone. BUUUUTTTT ... the LR atty is designed to produce heat with less resistance (thicker wire, double wire, whatever???), so the amps go up as the resistance is reduced, producing more watts of power dissipation. The higher voltage "push" more through a standard atty and that's why everyone loves em. Also, 1/2 the batteries reduces the current "drain" ... available amperage.

 

[WillyB]

When someone says, "If you can't afford an HV mod, than LR attys which "simulate" HV vaping is your next best option." <This statement would by default presume that HV vaping is the superior option.

Doesn't seem to 'presume' that to me. Seems to address a preference that some folks have. HV vaping increases the WATTS (Power = heat, throat hit). If you want more WATTS using a lower ohm atty is another option.

But am I correct in assuming that the voltage we vape at is irrelevant? We are just looking for a higher current by using a higher voltage with the same atty?

Most gauge the vaping experience by the WATTS produced. Many folks are looking for higher/more Power (WATTS). If folks like 9W vaping that can achieved with a 1.5Ω atty @ 2.5A. To get that we need 3.8V. A Joye 510 needs about 2A for 9W. To do that we need 4.4V. Seems voltage is quite relevant and an integral part of the equation. Power is the amount of current times the voltage measured in WATTS.

Are we really just discussing two different methods of achieving the identical desired results? On the surface it looks like the higher voltage mod is just consuming more power to achieve the same results.

It's best to understand and use the correct terminology. Using the same atty to increase the Power (WATTS) we need to increase the voltage, which will then increase the Current. That should theoretically shorten run times, but most 5+ second hitters find themselves taking shorter hits as the WATTS increase.

Theoretically Vaping at 9W should be the same no matter how you get there, but with the vast array of atties and construction, standard, LR, HV and those who make them it's never that simple as to what combo suits folks.

Lots and lots of posts on these forums regarding the preferences and opinions of either approach.

 

[roadrash]

to add to the conundrum of vvv. You have a ton of different juice mixes and during the day you want different hits. Every time I have the perfect set up I look for something else. I have 2 vvs and 2 boosters and some original 510 standard bats and I use most of them during a day. I even tried a cart yesterday to see if it still worked the same. So I say you can never have enough of lv, hv, cartos or whatever. Personal preference and different strokes n all. :>)

 

[eHuman]

Let me throw up a disclaimer: I don't want anyone to take me as being argumentative. I am going to counter some statements with my understanding (which is the reason for the questions in the 1st place). I think many people don't understand WHY they get better performance at higher voltage, they just understand that they do.

Doesn't seem to 'presume' that to me. Seems to address a preference that some folks have.

To me this preference is likened to driving 60 in a porche over driving 60 in a vw. You "can" go faster in the one but if you don't intend to then that preference will merely cost you more to do the same thing as the other cheaper alternative. (It would be different if the preference was for the maximum speed potential, the porche and the higher PV both have greater potential).

HV vaping increases the WATTS (Power = heat, throat hit).

HP vaping increases CURRENT which increases watts consumed, (Higherer current is responsible for greater TH.
HP vaping at the same current increases the power consumed (not produced) in order to perform at the same level.

If you want more WATTS using a lower ohm atty is another option.

This is where I believe there is a flaw. (The terms "current" and "power" are mistakingly being interchanged). To restate that, If you want more current then the only 2 options are higher voltage OR lower resistance, either will get you there.

If you want more current (without adjusting voltage) then using a lower ohm atty is the method. Current is what produces the heat we are looking for not wattage. Wattage is the amount of energy required to produce that heat.

Most gauge the vaping experience by the WATTS produced.

That's why I'm asking. (Watts aren't produced, they are consumed). I understand that is the perspective but it is flawed. it is higher current that changes the quality/quantity of the vaping experience.

Many folks are looking for higher/more Power (WATTS).

I think it is more heat they are looking for to the atty which comes from higher current.

If folks like 9W vaping that can achieved with a 1.5Ω atty @ 2.5A. To get that we need 3.8V. A Joye 510 needs about 2A for 9W. To do that we need 4.4V. Seems voltage is quite relevant and an integral part of the equation. Power is the amount of current times the voltage measured in WATTS.

I agree that voltage is relevant. It is the easiest thing to adjust. Variable power supplies are common, variable inductance coils don't exist. We are on the same page here but because of differing understanding. Variable voltage is what I'm looking for with reason.

It's best to understand and use the correct terminology.

I agree

Using the same atty to increase the Power (WATTS) we need to increase the voltage, which will then increase the Current. That should theoretically shorten run times, but most 5+ second hitters find themselves taking shorter hits as the WATTS increase.

Flawed premise, correct conclusion. An increase in voltage will produce a higher amperage and the energy require to do so will increase as a result (watts).

This can be displayed by a phenomena that you do see and agree with. If I take two 3.7v 1200mAh batteries and:

Wire in series: (2s1p = 3.7v 2400mAh) Then discharge them at a rate of 1.2 amps (1200mA) then the batteries will last two hours. 3.083 ohm load using 4.44 watts to do it.

Wire them in parallel: (1s2p = 7.4v 1200mAh) Then discharge them at a rate of 1.2 amps (1200mA) then the batteries will last one hour. 6.16 ohm load using 8.88 watts to do it.

The higher voltage battery/same amperage configuration consumes twice the power in order to perform the same task. < That's what is behind my OP. A higher voltage/same atty = higher current confiration is responsible for the shorter run time and greater throat hit, less hit needed for satisfaction. That you cannot engineer around, you pay for what you get (power potencial for performance)

Theoretically Vaping at 9W should be the same no matter how you get there,

I don't agree at all.
1. Vaping at 24v with a 64Ω atty = .375A and 9 watts
2. Vaping at 12v with a 16Ω atty = .75A and 9 watts
3. Vaping at 8v with a 7.1Ω atty = 1.125A and 9 watts
4. Vaping at 4v with a 1.7Ω atty = 2.35A and 9 watts
5. Vaping at 2v with a .4Ω atty = 4.5A and 9 watts

All of the examples consume 9 watts (and let's say we use the same gauge nichrome wire to make all the attys, just vary the length in order to achieve our needed resistances).
#1 might not get an atty warm, #5 will burn an atty up, and the rest are scaled in between. (Component failure warnings are based on Amperage and it doesn't matter how you get there, amperage = heat. Power supplies have a maximum wattage that they can be operated at because by design they can only produce a fixed maximum amount of energy)

It is not until you find the amperage range that a given atty (fixed resistor) performs well at (by increasing voltage) can you say, "Theoretically Vaping at 1.5A should be the same no matter how you get there, the only variables that can be manipulated are resistance and voltage, but the wattage will ALWAYS be different.

it's never that simple as to what combo suits folks.

This is very true, but how we get to that quantitative level once it is known for each person is an exact science.

Which brings me to clarify my post. I can build a 1000v device that will perform the same as a stock 3.7v battery as long as the components that I use are rated for the higher wattage required to do so and I will by default consume more power in the process.

The typical range that a 2 battery (7.4v 1200mAh) VV setup can achieve using a 3.9Ω atty is roughly 1.28 - 1.92 Amps. (5v cut-off)

The typical range that a 1 battery 3.7v 1200mAh) VV setup can achieve using a 1.9Ω atty is roughly 1.31-1.952 Amps. (2.5v cut-off)

Both of these devices should perform identically for the same duration. Packaging size and price is the difference.

My understanding as to why an LR atty burns out quicker is due to higher current that eventually overcomes the power rating of the wire. If a smaller gauge nichrome wire is used to achieve the lower resistance rating while keeping the atty coil the same length than the power rating of the atty would logically decrease, also contributing to early failure. But if the same guage wire is used to make a shorter but lower resistance atty then it would be able to withstand a higher amperage than the smaller wire.

What I am looking for is a flaw in my understanding of electronics with using an LR atty and a single cell batt to achieve the same thing that the HV modders are getting.

-roadrash, I understand the variables presented by different juices, that's why I don't just make a fixed mod with 1 cell and an LR atty. I agree that variable voltage is the most convenient answer to varying current in order to customize the TH/vapor/flavor experience.

One problem that I see is that you can only practically lower the resistance of an atty so far accurately, while you can vary voltage infinitely. And that only if you build one yourself, they only come stock just under 2Ω to my knowledge.

I know this may sound pointed or argumentative, but please don't take it personal, it's just how I logically sift through information. My logic tell me that there is nothing wrong with this idea, but the fact that noone else haas come up with it tells me that there's something i'm missing maybe. I just don't think it's the wattage issue.

 

[Mattco]

...Well...there's a lot there that confused me. I'm going to throw Ohm's Law out here for that somebody who gets confuddled with how those numbers were reached:
I=E/R (I=amps, E=Volts, R=Resistance)
And you can calculate the watts by
"Watts=Volts X Amps"...or "Watts=VoltsXVolts (AKA squared)/resistance".

The volts and resistance are mainly fixed values that can be exchanged with other volts or resistances to get the right amount of amps or watts (heat output). And it depends on personal preferences (vapor, throat hit, ect...) and the juice variable (if it likes to burn hotter or cooler for the right amount of flavor, vapor, ect...).

From what I understand, eHuman, I totally agree with your logic. I find the math to be a little off though...
"1. Vaping at 24v with a 64Ω atty = .375A and 9 watts
2. Vaping at 12v with a 16Ω atty = .75A and 9 watts
3. Vaping at 8v with a 7.1Ω atty = 1.125A and 9 watts
4. Vaping at 4v with a 1.7Ω atty = 2.35A and 9 watts (I got 9.4)
5. Vaping at 2v with a .4Ω atty = 4.5A and 9 watts (5A and 10 watts)
...I know, I'm splitting hairs, sorry...

My understanding as to why an LR atty burns out quicker is due to higher current that eventually overcomes the power rating of the wire. If a smaller gauge nichrome wire is used to achieve the lower resistance rating while keeping the atty coil the same length than the power rating of the atty would logically decrease, also contributing to early failure. But if the same guage wire is used to make a shorter but lower resistance atty then it would be able to withstand a higher amperage than the smaller wire.

From what I understand, this is like a fuse. I don't understand why shortening the wire would enable a higher amperage. I think it has to do with the diameter of the wire. If it's 10ft or .01 inches, it will still only be able to handle a certain amperage before it burns out. And lengthening the wire itself would create a higher resistance, so it could handle a higher voltage, but it'll still hit that magic amperage level and break. But maybe I'm just stupid...don't know.

But this totally explains why people normally talk about watts. I didn't understand that before. And I think I just learned that amperage is important too because that can give you some indication of the life of your atty or carto. So in theory, a low amp rating with the correct amount of watts for your personal preference of vaping experience and flavor would be ideal. Or am I missing something? The lower the voltage, the higher the amperage and the quicker your atty or carto is going to burn up...because the metal in the wire itself can only handle so much heat with that much current. You could take short puffs on a .4ohm atty and not have any issue. Heat it up for as long as you would with a 24volt system and it'd die...I think there's something else in my head about electrolysis and the degradation of wire. If the wire isn't insulated, electrons escaping from the wire by other conductors (air, moisture, whatever) will eventually erode the wire (making a smaller diameter wire smaller and having less amperage capability)...does this sound correct? I know I'm missing something too, and I wish somebody would say what it is...

 

[Mattco]

To clarify...I think watts is more of a measurement of energy released. So yes, 9 watts is 9 watts and heat your juice the same no matter what voltage and resistance you use to get there. Higher amperage will get it hotter faster. The amperage rating is what's going to burn things up which makes a HV system more ideal and in theory will last longer. And HV will have a more immediate of a reaction when you hit the button. The 2V .4ohm used as the example would take a much longer time to heat up.

 

[eHuman]

OK we agree on some but not all. Good catch on the math, may have been a copy paste function because I didn't like my 1st example.

From what I understand, this is like a fuse. I don't understand why shortening the wire would enable a higher amperage.

(ADDING THIS AFTER THE FACT) I thought I read shorting, thus the original response, but you said shortening, lol sorry. Shortening a wire will have no practical advantage or disadvantage (unless you meant the atty wire or coil)

Look at the first formula you pasted of ohms law I=E/R. When you short a wire you decrease it's resistance to a theoretical zero ohms (depending on the purity of the shorting material). If "E" stays the same but "R" decreases then I will increase.

The only place that wire diameter comes into play is in how much current can flow safely before it burns up the material (a short will cause an open). Wire is rated by voltage and Amperage maximums. A 10' thick wire and a 1/64th" thick wire should both have a resistance of zero ohms.

One thing to consider about wattage:
When you see a wattage rating on a power supply, it is referring to the maximum watts that the device can produce safely. A power supply or battery doesn't consume watts, it produces them.

When you see a wattage rating on an electrical device, it is referring to to the maximum watts that the device will require in order to operate safely. A radio or and e-cig does not produce watts, it consumes them. Often a wattage rating is not found on an electrical device, an amperage rating is because that is what is importance to the safe operation of device itself

If your power supply is rated at 12vdc 500watts, and your load is rated at 12vdc 200 watts, then you can safely run 2 of these loads on the same power supply. A third one will attempt to draw 600 watts from the source, overheating it and causing a power source failure.

On that same power supply If you place a load that is rated to be operated by 3v 50 watts then the voltage being 4x that of the engineered value will likely cause too much current and fry the load. (I=E/R, R remained constant, E increased, I must increase, which increases P or watts, but not enough to overload the power supply, just current increase enough to fry the electrical load).

So in theory, a low amp rating with the correct amount of watts for your personal preference of vaping experience and flavor would be ideal. Or am I missing something?

If I'm correct then I think what you are missing is that the wattage is irrelevant. At a given amp rating no matter how many watts are required to achieve it, the vape experience should be identical. Example:
4v battery 2Ω atty (2amp) (8 watts)
8v battery 4Ω atty (2Amp) (16 watts)
It only takes twice as much power in the 8v (2 battery) example because you are simultaneously performing the same thing with both batteries. You are using 8 watts per battery in either case in order to achieve a 2Amp rating which is what heats our atty (the amperage not the wattage)

The lower the voltage, the higher the amperage and the quicker your atty or carto is going to burn up...

Just the opposite. Lets keep the same load (atty) but vary the voltage:
8v battery 4Ω atty (2Amp) (16 watts)
4v battery 4Ω atty (1amp) (4 watts)
If R is constant then E and I are directly proportional, (voltage goes up/current goes up. voltage drops/current drops).
If E is constant then R and I and INdirectly proportional, (R goes down/I goes up, R goes up I goes down). This is why when on the same battery if your atty starts to get gummed up the resistance (R) increases which decreases current (I) and performance begins to suffer. The performance drop is not because the power/watts (P) also happened to drop. the watts required to operate the circuit decreased because we ran less energy (I).

the metal in the wire itself can only handle so much heat with that much current.

YES! but wire is not rated by wattage, it is rated by a maximum amperage at a maximum voltage.

I think there's something else in my head about electrolysis and the degradation of wire. If the wire isn't insulated, electrons escaping from the wire by other conductors (air, moisture, whatever) will eventually erode the wire

YES! but we are presumably using Nickel/Chromium wire that does not readily oxidize or corrode, and has a calculated resistance per linear measurement (ohms per foot rating) making it an awesome material for atomizer manufacturing.

ADDED: We operate our attys close to the failure point because we desire the instant heat that it produces at in the small package we need. A toaster coil is an "atty" that can withstand heat fora much longer period of time before burning up because the guage (thickness) is greater and is rated to handle more current before burning. Make no mistake, the 1 to 2 amps that we typically vape at is found in few other small electrical cicuits outsdie of heaters. Your Ipod lasts a long time on a smaller battery because the current draw is minimal and it uses up power at a much slower rate.

 

[Mattco]

I'm really enjoying this conversation. I'm in the same boat with trying to figure out what to build and trying to get all to work out right in my head.

Let's go with what we experience:
5v with 3.2ohm=1.56amp (7.8 watts) 3.7v with 3.2ohm=1.16amp (4.3 watts)
5v with 1.7ohm=2.94amp (14.7 watts) 3.7v with 1.7ohm=2.17amp (8.1 watts)

5v with 3.2ohm has a similar experience as 3.7v with 1.7ohm because of the wattage...that's what is generally reported (although I haven't tested this myself).

I can see why you're saying watts are irrelevant, but I do think that it's a certain wattage you're aiming for, no matter how you get there. I see wattage as energy used or heat produced, consumed, etc. If you kept your amperage constant throughout variable voltages and resistances, you're going to have different experiences. Similar wattage will produce similar experiences.

I think it's a give and take. If you want a small mod, the higher amperage is going to cause issues with a LR atty sooner. A bigger mod with a lower amperage is going to have a longer lifespan.

I'm beginning to think of this in the terms that the wattage is how hot the atty gets. And the amperage is how fast it gets hot. Both are equally important in the vaping experience.

I'm not seeing any flaws with this. And please point them out if anyone finds them wrong.

 

[zerotao]

Just to be pedantic; A Watt is the unit by which "energy conversion" is measured. Technically it is not the amount consumed nor the amount produced, but a measure of the amount converted.

W = V^2/ohm = A^2*ohm = V*A = "true power" of a circuit.

Everyone saying that Watts = heat (approximately) are correct in that it is the energy conversion to heat that is being targeted. This can be achieved (as noted above) by varying the amps, voltage or resistance.

The easiest to do (in a small space with fixed components) is to vary the voltage.

Varying the amps in a battery powered device is generally difficult (outside of a very narrow range) and can result in ... some of the mishaps seen on unprotected (or faulty protected) batteries. Even varying the amps within that range is stressful on most batteries if it is done too rapidly/frequently.

Varying the resistance, and still achieving the desired result (ie a hot piece of wire) is simple in a circuit (seen in some types of variable light bulbs) but requires more space.

 

[zerotao]

Another note:
The nichrome wire fails primarily due to the rapid heating and cooling of the wire which creates areas of stress which will eventually fail (ie break the wire). I imagine that there is a loss of atoms as well but I am unsure of the chemistry in nichrome wire under stress. Any flaws or impurities in the wire will also cause it fail sooner.

This is also seen in light bulbs where (in addition to the loss of tungsten atoms) the rapid heating and cooling eventually cause the filament to break. This can be witnessed by a flickering bulb burning out faster then a bulb that is always on.

 

[eHuman]

Just to be pedantic; A Watt is the unit by which "energy conversion" is measured. Technically it is not the amount consumed nor the amount produced, but a measure of the amount converted.

100% agreed. I use the terms that I do because it is easier to make my point about what wattage isn't doing for us.

The easiest to do (in a small space with fixed components) is to vary the voltage.
Varying the amps in a battery powered device is generally difficult

But varying the voltage does vary the amperage.

 

[eHuman]

Another note:
The nichrome wire fails primarily due to the rapid heating and cooling of the wire which creates areas of stress which will eventually fail (ie break the wire).

True but that is only because of how we use them. We pulse our attys for relatively short periods of time while wet and we let them cool down. Turn on the amps on a dry atty and don't pulse it and we see a different story. An LR atty properly wetted will blow in a couple of seconds with too much amperage. So will a normal atty for that matter.


My dilemma ultimately for the mod I want to build comes down to finding or making an LR atty that doesn't use a smaller guage wire to achieve it. The length of the coil would have to be shorter and at a certain point would not be a sufficient enough surface area heated to vaporize our juice effectively.

 

[eHuman]

Let's go with what we experience:
5.1v with 3.2ohm=1.59amp (8.1 watts)
3.7v with 1.7ohm=2.17amp (8.1 watts)

I modified your examples to help answer the question that I have. (Unfortunately I don't have the gear rigged up to test, but this would answer it).

Since using variable voltage, bumping that 5v to 5.1 will give us the same wattage but a .58A difference between the two. If the two were compared but indistinguishable in performance then wattage plays a bigger role than I understood it to be able to. By my theory the 3.7v device should perform better as the amperage is higher. And that is really mypoint or goal to determine that.

To be fair comparing the 2 circuits below using the same current but different wattages would complete the testing. and should confirm what ever is found in the first test.

I have 1.9Ω, 3Ω, and 3.9Ω attys to play with so I will use those values. Both will be concidered variable voltage, 1 and 2 cell models with regulators.
6.3v with 3.9Ω=1.61amp (10.18 watts)
3.07v with 1.9Ω=1.61amp (4.96 watts)

If this vaping experience is the same then it is the current responsible for the heat, TH etc. If the HV is better than it is because of the higher wattage.

Both of the tests results should support each other either way.

I am still coming down to this, I'm going to have to try both to find out.

 

[bigblue30]

In the same light as you said "I don't want anyone to take me as being argumentative."
I am going to try to answer this in the same way.

I have been looking at this for a few days and knew there was no way to give a short answer. So be warrned....this is a long answer

This is a great thread. This subject is one of the first topics that got me hooked on this board.

Let’s see if I can throw some basics out there to help with this discussion. I know for some this is old hat.

First thing should be Ohm’s law… A good on-line ohms law calculator is this one:

Ohm's Law Calculators


If you are “old school” like me you can just use your calculator or slide rule.

Before we begin we have to understand a few terms.

“E” Electromotive force, Is a difference in charge that is stored as electrical potential energy known as emf. It is emf that causes current to flow in a circuit. Some people call this voltage. It is measured in Volts.


“E” is a potential energy, it does not do any work and in our case it does not make heat, cause the e-liquid to vaporize, or give throat hit. An easy way to think of EMF is to think of it as water pressure in a hose. Water pressure does not get you wet, water your flowers, or fill up your pool.


“R” Is the electrical resistance of an object. It is a measure of its opposition to the passage (or flow) of a electric current. Think of this as a water valve. As you open or shut the valve more or less water flows. Again “R” alone does no works for us or heats up the atty. “R” is measured in Ohms.

“I” Electric current Is a flow of electrons or the rate of flow of electrons through a conductor ( wire, resistor, switch, atty….). In a Mod this flowing electric charge is carried by moving electrons. It is measured in Amps. One amp equals about 6.242 × 10 to the 1018 electrons flow past a given point per second. The electrons flowing through the atty wire is what heats up the atty, causing vapor and throat hit.

I know that what I just said is Electronics 101 for a lot of you, but we need to understand that electrons flowing through the atty are what we care about.

Now that we know that electrons flowing through the atty causes heat, what can we use to compare all the different voltages and different atty resistances that mods have, to see how much heat these different variables can make at the atty?

I suggest we use The WATT. The WATT is the measurement of the rate of energy conversion, or in the case of a mod, how much energy does the atty consume or turn into heat. In an atty that consumed energy is converted to heat. In an atty, heat is all we care about. I do not care what the voltage is, what the atty resistance is, or what the current through the atty is as long as it does not not burn out. I care about how many watts the atty is using or how HOT the atty gets, because HOT equals throat hit and vapor.

Now that the Electronics 101 is covered, let's look at 201.

Let's look at a basic e-cig. A fixed voltage battery and a fixed resistance atty.

Let's use the values from this post…3.7 volts for the battery and 1.7 ohms for the atty.

Using WATTs this would be 8.1 (8.052) watts. (3.7 volts, 1.7 ohms, and 2.17 amps of current). So lets say that 8.0529 watts is your sweet spot with the atty and e-liquid you are using at this moment.

You then get a 5 volt mod but want that same sweet spot. You would have to find an atty with a resistance of 3.104 ohms (good luck with that). 5 volts, 3.104 ohms, and 1.610 amps = 8.052 watts. Watts lets us look at the heat when all the other values change.

If the above two atty’s have the same construction, then they will heat and hit the same because they are both heating to 8.052 watts. No difference at all.

But let's be realistic here, real world. No two attys in the world are the same, even from the same box. So if your current atty, current battery voltage , and the current juice you are using is able to deliver that sweet spot at this moment, I can guarentee that the next atty, battery, or juice will be different.

This is why variable voltage is so important to help you find that perfect sweet spot every time.

Each atty has a fixed resistance, so the only way to tweak the watts is to increase or decrease the voltage (pressure), which in turn increases and decreases the current (electrons flowing), which in turn increases or decreases the watts or heat the atty is making.

So even if you say “ 3.7 or 5 fixed volts is all I need” You are missing out on the ability to “tweak” even .5 volts up or down to be able to adjust for different attys and liquid.

With all of that having been said:

But am I correct in assuming that the voltage we vape at is irrelevant? We are just looking for a higher current by using a higher voltage with the same atty?

Yes, Voltage, Current, and resistance on their own are irrelevant. Not until you talk Watts do any of them on their own make any sense. WATTs take into account all three of the above values. Just like your analogy of the porsche and VW. Going 60 mph does not take into account that you have to do it carrying 5 people.

Vaping at 6v with a 4Ω atty = 1.5a (1500mA) 9 watts
Vaping at 4.5v with a 3Ω atty = 1.5a (1500mA) 6.75 watts
Vaping at 3v with a 2Ω atty = 1.5a (1500mA) 4.5 watts

In the example above, a higher voltage source with a "standard" atty would give the same amperage as a lower voltage source with an LR atty, but it would consume more power in order to do it.

Yes, the 6 volt one above will consume more power, but at the same time it will be producing 2X the heat (watts)….better vapor and better TH. If all the above batteires have the same Mah rating then the 6 volt one will last as long as all the other and give better performance…That is if you think more vapor and TH is better.

Are we really just discussing two different methods of achieving the identical desired results? On the surface it looks like the higher voltage mod is just consuming more power to achieve the same results.

Looking at only current will not work to compare these two. Again that is why WATTs are important.

If you want more current (without adjusting voltage) then using a lower ohm atty is the method. Current is what produces the heat we are looking for not wattage.

Correct, but wattage tells us how much heat we are getting from the atty. If I said that I have 2 amps going to my atty…..that would tell you nothing….but if I said that my atty was running at 8 watts, you would have a good idea of the performance of my e-cig.

If you want more heat…. You have two choices. Increase the voltage or decrease the resistance. The current will then be a by-product of the two. There is no way to say that I am just going to increase the current without changing either voltage or resistance.

I know that the above is a simple statement, but in the e-cig world all we have to adjust is the voltage or the atty, and the current and wattage will follow.

I agree that voltage is relevant. It is the easiest thing to adjust. Variable power supplies are common, variable inductance coils don't exist.

I agree but only in a DC circuit. In AC, that is not true. So we should just look at an atty as a fixed resistor.

Wire in series: (2s1p = 3.7v 2400mAh) Then discharge them at a rate of 1.2 amps (1200mA) then the batteries will last two hours. 3.083 ohm load using 4.44 watts to do it.

Wire them in parallel: (1s2p = 7.4v 1200mAh) Then discharge them at a rate of 1.2 amps (1200mA) then the batteries will last one hour. 6.16 ohm load using 8.88 watts to do it.

I think you switched your series and parallel above series = 7.4.

Am I understanding what you said above? The first example does ½ the work (4.44 Watts) and last 2 times longer than the one doing 2X the work (8.88) watts?

The higher voltage battery/same amperage configuration consumes twice the power in order to perform the same task.

You have to compare WATTS to WATTS to get the same task. 4.44 watts X 2 hours =8.88 watthours. 8.88 X 1 hour = 8.88 watthours. Power = Power here with your numbers.

The typical range that a 2 battery (7.4v 1200mAh) VV setup can achieve using a 3.9Ω atty is roughly 1.28 - 1.92 Amps. (5v cut-off)

The typical range that a 1 battery 3.7v 1200mAh) VV setup can achieve using a 1.9Ω atty is roughly 1.31-1.952 Amps. (2.5v cut-off)

Both of these devices should perform identically for the same duration. Packaging size and price is the difference.

The 7.4 volt will be putting 14 watts, the 3.7 one will be putting out 7 watts. Again this is why you need to look at watts and not current and resistance.

 

[zerotao]

bigblue30,

thank you for clearly stating what I was attempting to get across (this is why I don't teach...)

 

[eHuman]

Awesome post bigblue,

Yes (good catch) I reversed those two in that example, lot of thinking going on. It's been a long time (25yrs) since my electronics education and lack of use for the last 1/2 of that haven't helped much.

I want to add but will have to do it later.

 

[Bubo]

Too many words.. Need more pictures...

Just kidding - this helps me alot!

 

[bigblue30]

Awesome post bigblue,

Yes (good catch) I reversed those two in that example, lot of thinking going on. It's been a long time (25yrs) since my electronics education and lack of use for the last 1/2 of that haven't helped much.

I want to add but will have to do it later.

eHuman,
Thanks for understanding that this information was posted not to argue or lecture, but simply as an ongoing effort to continue and expand on a great discussion.

My EE is more than 36 years old. Luckily, I was able to keep it "fresh" working for IBM for 32 years. After retiring I found this board and am happy to share my "old school" approach

 

[eHuman]

No blue, you present very similar to how I think and present. I try to layout why I understand something to be a certain way, so anyone with understanding can recognize for themselves what I am missing from the equation.

I am still partly hung up on wattages effect on the adjustable sweet spot, due probably more to the practical application than anything else.

Here is why:
Refer to Wire Specs and Current vs.Temperature chart at bottom of PnJ Resources, LLC : Nichrome 80

I can make any atomizer I want with any resistance rating in any gauge or length that I desire only restrained by the properties of the materials that I use. I am more limited if I have a pre-existing enclosure that I must place the atty in, But I am not limiting myself to that.

My real unknown value is the full physical temperature range at which vaporization of our liquid can take place. That will dictate which gauges of wire I can use in order to achieve the desired results.

Since it it possible to make the same resistance coil out of various gauges of wire, then length of coil is my primary obstacle in designing a coil that can withstand more heat before burning the wire and causing an open.

The heavier gauge I use the shorter the coil must become, and the lighter the longer for a given resistance. At a certain point the coil can be physically too long for the enclosure size that I am comfortable choosing. Or too short to have enough surface area to vaporize the liquid at the volume and rate that I need.

TH may indeed be a product of wattage and amperage (which are slaves to Voltage and resistance) but vaper volume is a byproduct of the surface area of the coil which determines the rate of vapor production at that sweet spot TH.

My understanding is that current determines the temperature that nichrome wire reaches, How many watts are need to do so will be a result of how much energy needs to be converted to reach it. But too much heat for a given atty will fry it.

This is why the power factor (Not technically the correct term for DC voltage) is irrelevant (but probably in my mind only) because there should technically be more than one configuration wattage wise to obtain the heat I need in a more robust configuration than we currently have. But even if it turns out that it ends up being the same wattage in all cases, that is not the important part - just the price that has to be paid in order to get there.

It is technically possible (in my mind) to engineer the correct atty with the temperature characteristics that will both operate in the heat range needed for proper vaporization and be alot tougher to physically burn up. Then design my packaging for the optimized atty rather than fitting the best one I can in a predetermined size package..

And with all of this thought going into this, no I'm not looking into marketing, I'm just a tinkerer at heart.

My 1st obstacle is determining temperature ranges.