High voltage high res Vs. low volt low res

[J.R. Bob Dobbs]

what is the difference between High resistance attys with high volts Vs. Low resistance and low voltage ? theoretically you could get the exact same wattage either way. My only variable voltage is a twist, and anything over 4.0 seems too much on my 2.4 and lower stuff. But if i pop on a 1.8 stardust at 3.2 it tastes just as awesome as 4.2 with a 2.4 stardust.

ive seen the safe vape chart , i just do not fully understand why one is better than the other. I know high volt + low resistance = hotter vape and low volt with high resistance would be cooler vape. i get how that could help with some juices. like drink flavors or menthol that you want to taste cool etc...

 

[kiwivap]

what is the difference between High resistance attys with high volts Vs. Low resistance and low voltage ? theoretically you could get the exact same wattage either way. My only variable voltage is a twist, and anything over 4.0 seems too much on my 2.4 and lower stuff. But if i pop on a 1.8 stardust at 3.2 it tastes just as awesome as 4.2 with a 2.4 stardust.

ive seen the safe vape chart , i just do not fully understand why one is better than the other. I know high volt + low resistance = hotter vape and low volt with high resistance would be cooler vape. i get how that could help with some juices. like drink flavors or menthol that you want to taste cool etc...

4.2 volts and 2.4 ohms - 7.35 watts and 1.75 amps
3.2 volts and 1.8 ohms - 5.68 watts and 1.77 amps

One is a cooler vape than the other. The cooler vape at 5.68 watts actually has a slightly higher amp draw, but not by much.

Those were going on the figures you posted. A lot of people go higher than 3.2 volts with 1.8 ohms though, because they are using low resistance to get a hotter vape.

3.7 volts and 1.8 ohms - 7.6 watts and 2.05 amps.
4.0 volts and 1.8 ohms - 8.8 watts and 2.2 amps.

The more common way of using low resistances results in greater watts, but also a higher amp draw. The battery will drain faster because of that.

 

[junkman]

Lower res generally implies lower thermal mass, all else equal. Therefore a lower res set up should be more responsive, i.e. heat quicker then a higher res set up. However, while that sounds reasonable, I am not sure it is true, because to obtain the same heat, you would use less volts on low res, so using higher volts may offset the lower thermal mass.

So, I am sure I have cleared everything up for you.

In the end the watts control the heat, and over a reasonable amount of time the heat should be the same for same watt setups regardless of the res/voltage.

 

[ChrisGaynor]

I like using my lavatube at 5.0 volts and a 2.5ohm cartomizer. As the battery drains, I bump the voltage up a couple notches to 5.2 or 5.3 volts. Warm vape is best for me.

 

[kiwivap]

Lower res generally implies lower thermal mass, all else equal. Therefore a lower res set up should be more responsive, i.e. heat quicker then a higher res set up. However, while that sounds reasonable, I am not sure it is true, because to obtain the same heat, you would use less volts on low res, so using higher volts may offset the lower thermal mass.

Yes, I think so too. The sacrifice using low res will be in the higher amps.

 

[LucentShadow]

Provided that you are shooting for the same wattage with the high and low resistance setup, there should be no real difference.

There could be some physical differences that may affect performance, such as diameter and length of resistance wire, but those are fairly variable in any situation.

Electrically, if you run a 3.7v battery through a booster to get a higher voltage, you'll still be pulling higher amperage than you might expect from doing a simple output voltage / resistance calculation, so there really isn't any benefit to the battery, either (IMO.)

 

[sawlight]

4.2 volts and 2.4 ohms - 7.35 watts and 1.75 amps
3.2 volts and 1.8 ohms - 6.68 watts and 1.77 amps

One is a cooler vape than the other - not by a huge amount but 0.5 watts can make a real difference when it comes to juice taste too. The cooler vape at 6.68 watts actually has a slightly higher amp draw, but not by much.

Those were going on the figures you posted. A lot of people go higher than 3.2 volts with 1.8 ohms though, because they are using low resistance to get a hotter vape.

3.7 volts and 1.8 ohms - 7.6 watts and 2.05 amps.
4.0 volts and 1.8 ohms - 8.8 watts and 2.2 amps.

The more common way of using low resistances results in greater watts, but also a higher amp draw. The battery will drain faster because of that.

Ummmm....... No! 3.2v at 1.8 ohms is 5.69 watts at 1.78 amps. Sorry, had to correct that one. Not picking on you Kiwi, just caught that one off hand!
Many people, myself included, believe you get better battery life. Some claim that the 15% (or so) loss of power from the regulation circuitry, I can't say. But I can say I get higher run times on higher ohm carto's at higher voltage. Take that as you will?

 

[kiwivap]

Ummmm....... No! 3.2v at 1.8 ohms is 5.69 watts at 1.78 amps. Sorry, had to correct that one. Not picking on you Kiwi, just caught that one off hand!
Many people, myself included, believe you get better battery life. Some claim that the 15% (or so) loss of power from the regulation circuitry, I can't say. But I can say I get higher run times on higher ohm carto's at higher voltage. Take that as you will?

Hi Sawlight - I did a typo putting 6 instead of 5 so I accidentally put 6.8 instead of 5.8 for the watts. Will do an edit.
I didn't round them up - so I have 5.68, you have 5.69. I put 1.77, you put 1.78.
Its actually 5.6888 recurring and 1.7777 recurring.
Thanks for spotting the 6 instead of the 5 there.

 

[J.R. Bob Dobbs]

thanks for the great replies so far people!

I know some flavors you def want a cooler vape, like with soda flavors, fruit flavors etc.. When i vape my HHV i normally have a 2.4ohm kanger t3 and my twist is on 4.0 or maybe a bump higher. Like i said i have a copy of the save vaping chart and sometimes push the limits on both ends with new flavors. I just don't understand the debate of low volt+ low Resistance vs high volt and high resistance. Seems like they come out about the same flavor wise. but if low res+ low volt = high amp draw then ill avoid it in the goal of longer battery life. I've noticed i get 5-6 hours out of my twist(650mah) under normal useage at 4.0v with a kanger t3 on it. But i dont vape to the cutoff, i normally take 5-6 sec vapes. I would love to see more input on this subject.

 

[kiwivap]

I just don't understand the debate of low volt+ low Resistance vs high volt and high resistance. Seems like they come out about the same flavor wise. but if low res+ low volt = high amp draw then ill avoid it in the goal of longer battery life.

Low res + low volts shouldn't give you a high amp draw:
4.2 volts and 2.4 ohms - 7.35 watts and 1.75 amps
3.2 volts and 1.8 ohms - 5.69 watts and 1.78 amps

So for the lower res +lower volts there isn't much different in amps. By .03 amps.
I don't know why that would be debated really.

Most people don't use low res and low volts - they want more heat, so need to generate more power. Looking at the numbers above you can see there isn't much difference in the amps, but look at the difference in watts. The low res +low volts is giving a cooler vape.
Increasing the volts with 1.8 ohms is going to increase the amp draw. Example:
3.2 volts and 1.8 ohms - 1.79 amps.
3.8 volts and 1.8 ohms - 2.11 amps

 

[sawlight]

The real difference comes when you get to 3 ohm and higher cartos.
5 volts and 3 ohm is 1.66 amps 8.33 watts.
I've found I get an hour, or more, run time when using the 3 ohm carto's. YMMV, as there are many that disagree that this works.

 

[junkman]

The real difference comes when you get to 3 ohm and higher cartos.
5 volts and 3 ohm is 1.66 amps 8.33 watts.
I've found I get an hour, or more, run time when using the 3 ohm carto's. YMMV, as there are many that disagree that this works.

Yeah, it is kind of strange there is no consensus on battery impact of differing resistances. Some will heatedly argue that low res uses less battery, others that high res uses less, still others that it makes no difference at the same wattage.

I am sure that it depends on the device to some extent and watt level but I sure wish there was a consensus - although I am not patient enough to do the tests myself to provide the answer.

 

[sawlight]

Right, and the effacy of the regulation circuit plays into this a lot as well. Most claim to be 85% efficient, I'd like to think there are boards with a higher effacy, but again, I can't prove it!
Then with the inconstancy I've been getting with carto's of late, that makes it even harder to prove one way or the other.

 

[Whiplash]

I too have been pondering this problem for some time. The math does not always match reality in that some batteries are not capable of the demand. They cannot discharge fast enough, so a 3.7 Volt battery across 1.8 Ohms does not necessarily produce 7.6 Watts because the battery voltage drops as soon as a connection is made.
With quality batteries, science prevails; otherwise, we get confusion.
How do you keep from burning your 2.5-ohm cartos at 5 Volts? (10Watts) I’ve never been able to run over 7.

 

[sawlight]

I too have been pondering this problem for some time. The math does not always match reality in that some batteries are not capable of the demand. They cannot discharge fast enough, so a 3.7 Volt battery across 1.8 Ohms does not necessarily produce 7.6 Watts because the battery voltage drops as soon as a connection is made.
With quality batteries, science prevails; otherwise, we get confusion.
How do you keep from burning your 2.5-ohm cartos at 5 Volts? (10Watts) I’ve never been able to run over 7.

Yes, you also have battery "sag" to figure in, when loaded hard it will drop more but I can't give an honest answer of how much, but I'm certain .2-.3v is pretty realistic.
I don't run 2.5 ohm carto's at 5v, I use the easy rule of resistance plus 2 and it keeps me right in the 8 watt range. A 2.5 ohm would be run at 4.5v which is 1.8 amps at 8.1 watts.

 

[Whiplash]

In a perfect world (Quality batteries and cartos), I have to say it is better to use higher voltage and higher resistance.
Two ways to get 7.7 watts:
1.5 Ohms and 3.4 Volts = 2.3Amps
3.0 Ohms and 4.8 Volts = 1.6Amps
Tells me we get better battery life at high Volts/High resistance.
Are there other factors to consider? Will the temperature be the same?

 

[junkman]

In a perfect world (Quality batteries and cartos), I have to say it is better to use higher voltage and higher resistance.
Two ways to get 7.7 watts:
1.5 Ohms and 3.4 Volts = 2.3Amps
3.0 Ohms and 4.8 Volts = 1.6Amps
Tells me we get better battery life at high Volts/High resistance.
Are there other factors to consider? Will the temperature be the same?

Problem with that is Watts is the measure of energy use. Amps is not the measure of how much energy is consumed.

I have seen it equated with water in a pipe. The pipe size is the ohms. To get a set amount of water out of the pipe (watts) you can either use a small pipe with high pressure (high amps) or a large pipe at lower pressure (low amps).

In the end the same amount of water (stored energy) is moved.

of course this assumes perfect efficiency, etc. as sawlight was pointing out, isn't really the case. Still, amps is not the correct measure of how much energy is used.

 

[sawlight]

In a perfect world (Quality batteries and cartos), I have to say it is better to use higher voltage and higher resistance.
Two ways to get 7.7 watts:
1.5 Ohms and 3.4 Volts = 2.3Amps
3.0 Ohms and 4.8 Volts = 1.6Amps
Tells me we get better battery life at high Volts/High resistance.
Are there other factors to consider? Will the temperature be the same?

The other "factors" are that it's still a 3.7v battery so theoreticly it's still seeing the 2.3 amp load either way. Which I have to agree, makes sense. The reason people say you don't get the better battery life is no matter what the voltage, it's still a factor of watts and input voltage that creates the amperage. And Ohm's law verifies this. Then you have to factor in the 15% effacy loss of the regulation circuit.
This is where the detractors of my longer battery life theory make solid points! Now on the other hand, we take a Buzz Pro, which uses two 3.7v batteries, which gives us a 7.4v start, then we are lowering the voltage down to meet our desired effect. So with Ohm's law we are now saving battery life and only loosing the 15% effacy of the regulation circuit.
See how this gets confusing?

 

[unloaded]

This all goes back to when there were only unregulated devices and attys were all about 3.5 ohms. The only way to get a better vape was to stack batteries to get either 6v or 7.4v All the bragging about how much better the vape was got those who were unable or unwilling to stack batts jealous. The low res attys started appearing so they could simulate hi res/voltage vaping. Next came regulators that would step down the voltage of stacked batts but they dumped the excess voltage as heat. The lower you set the voltage the less efficient they were. Next came the more efficient ever-cool regulators which ran without dumping heat and gave much better battery life, still required stacked batts though. Now we are using the boosters which boost the voltage from a single battery. They are pretty efficient throughout their voltage range. If you run a LR atty at 3.7v amps will be higher between the booster and the atty but lower between the battery and the booster. If you put a HR atty on it and run 5.5v the amps between the booster and atty will be lower but it will be higher between the battery and the booster. If both attys are running the same wattage the battery life should be about the same.

 

[sawlight]

This all goes back to when there were on unregulated devices and attys were all about 3.5 ohms. The only way to get a better vape was to stack batteries to get either 6v or 7.4v All the bragging about how much better the vape was got those who were unable or unwilling to stack batts jealous. The low res attys started appearing so they could simulate hi res/voltage vaping. Next came regulators that would step down the voltage of stacked batts but they dumped the excess voltage as heat. The lower you set the voltage the less efficient they were. Next came the more efficient ever-cool regulators which ran without dumping heat and gave much better battery life, still required stacked batts though. Now we are using the boosters which boost the voltage from a single battery. They are pretty efficient throughout their voltage range. If you run a LR atty at 3.7v amps will be higher between the booster and the atty but lower between the battery and the booster. If you put a HR atty on it and run 5.5v the amps between the booster and atty will be lower but it will be higher between the battery and the booster. If both attys are running the same wattage the battery life should be about the same.

And there lies the problem! A lot of "should's" and "might's" and "could's" with neither side being able to prove anything either was as of yet! I "think" I get better life with the lower res attys, but how do you prove that as a normal vaper? Maybe I didn't hit it as much, maybe I took shorter drags that day? I have no hard data for either side so take it for what it's worth, nothing!

On a side note, I was in a similar conversation a while back and I showed the watts of 3 ohms at 3.7v for someone when a newer poster came in saying there was no way anyone would vape like that! I had a chuckle then told him we ALL used to vape like that because that's all we had back then!
Ah, the good old days! Man I don't miss them!