there seems to be a little confusion and accidental mis-infomation being spread around here about how all of this works, and i'm sure most of it is simply by accident or because people have been misinformed or just misunderstand, as it really can get pretty complicated and hard to understand. i'll try to explain things in detail here but in an understandable way. if you have any questions or comments i'm happy to hear them and to answer anything you are wondering
what some people have said on this board before, and what is the absolute end-all be-all truth, is that the ONLY thing that matters, in the end, is the wattage that you are putting through your coil(s). for these examples i'm going to list the ohms that the coil in the carto/atty, the voltage, amps, and watts. single or dual coil doesn't affect the wattage or amperage calculations when you use the equivalent resistance (ohms) of the dual coils. what i mean here is, if you have a 2 ohm rated dual coil carto, what you actually have are two coils that are each rated at 4 ohms, and that are wired in parallel. this means that EACH coil is acting as a single 4 ohm coil, and whatever voltage you are using on the carto will put amps through each coil as though each is a 4 ohm coil. the (simlified) reason that the coil gets rated at 2 ohms is because, when you have two coils in parallel, the current through the entire device is the sum of that through both of the coils (doubled that of one by itself). what this (in theory) would do is produce the amount of vapor that two separate coils would produce, albeit those coils would be ones that are rated at their individual resistance. one downside of this arrangement is that you only have so much surface area for the coils to heat up juice on, and to wick juice off of, and as such, you are more likely to have one (or both) coils not getting fully wet, all of the time, and thus, not producing at full potential. you also are getting less total wattage on each coil, thus producing cooler vapor, although more of it than just one coil rated at the same ohms.
what this would mean is that a 2 ohm rated DC carto should produce a little cooler vapor than a 2 ohm rated single coil unit, though which one produces more vapor would be dependent completely upon the design of each unit and the thermodynamic properties of them. personally i don't recall all of the theory behind all of that, and as such, i can't remember if the hotter single coil should produce more vapor than the cooler dual coils, but i do know that it would also depend on the type of juice you are using (the mix ratio) and upon how wet they are etc. but since DC units are usually arranged vertically along the central axis of the carto, you can bet that both coils are not going to be constantly as wet (esp after a few puffs) as a single coil unit that is run either vertically, but at the bottom of the central axis, or horizontally at the bottom of the carto. this is because the juice is naturally going to tend towards the bottom of the unit, and thus, the top coil on a DC unit is going to get dryer quicker.
now for some calculations: a 1.7 ohm coil that gets run at 3.5 volts draws 2.06 amps and generates 7.21 watts (which is turned into heat to vaporize the juice)
now take a 2.8 ohm coil and run it at 4.5 volts, this coil will draw 1.607 amps and generates 7.23 watts
these two coils, assuming they are built exactly the same, will produce EXACTLY the same vapor in every way, shape, and form. if they are identical in every way except for the resistance of the coil inside of them, they will be identical... there would be no difference in the heat of the vapor or the amount of it, because the wattage is the same, and thus the heat produced by each coil has to be the same.
if you had a 2.2 ohm coil and put it at 4 volts, you would be at 1.81 amps and 7.27 watts; again, the same exact result as the two above.
this proves that the common misconception that you can't get the same vaping experience from an LR as you can from an SR is just that, a misconception. the only thing that could make an LR give a better experience (from a VV PV) is a better inherent design of the atty/carto. otherwise, you are really better off going for an atty/carto that will be the highest resistance that you can use while still giving you the maximum possible current IF you set your PV at it's highest voltage. this will allow for the MOST flexibility (in that, you can lower the voltage down from max and realistically utilize MUCH more of the voltage range) whereas if you were to use an atty that maxes out the current (2.5 amps for many PV's) at only 4 volts, for example, then you are getting nowhere by setting the PV higher than that, because the unit will kick in it's current limiting function and force the voltage down to the point where the current stays at or below 2.5 amps. this will give you less options, as you can only go between 3 and 4 volts, instead of being able to go between 3 and 6 volts.
hope this helps everyone
p.s. i am an electronic engineering technologist and, as such, have a fair bit of experience and background in this topic...
what some people have said on this board before, and what is the absolute end-all be-all truth, is that the ONLY thing that matters, in the end, is the wattage that you are putting through your coil(s). for these examples i'm going to list the ohms that the coil in the carto/atty, the voltage, amps, and watts. single or dual coil doesn't affect the wattage or amperage calculations when you use the equivalent resistance (ohms) of the dual coils. what i mean here is, if you have a 2 ohm rated dual coil carto, what you actually have are two coils that are each rated at 4 ohms, and that are wired in parallel. this means that EACH coil is acting as a single 4 ohm coil, and whatever voltage you are using on the carto will put amps through each coil as though each is a 4 ohm coil. the (simlified) reason that the coil gets rated at 2 ohms is because, when you have two coils in parallel, the current through the entire device is the sum of that through both of the coils (doubled that of one by itself). what this (in theory) would do is produce the amount of vapor that two separate coils would produce, albeit those coils would be ones that are rated at their individual resistance. one downside of this arrangement is that you only have so much surface area for the coils to heat up juice on, and to wick juice off of, and as such, you are more likely to have one (or both) coils not getting fully wet, all of the time, and thus, not producing at full potential. you also are getting less total wattage on each coil, thus producing cooler vapor, although more of it than just one coil rated at the same ohms.
what this would mean is that a 2 ohm rated DC carto should produce a little cooler vapor than a 2 ohm rated single coil unit, though which one produces more vapor would be dependent completely upon the design of each unit and the thermodynamic properties of them. personally i don't recall all of the theory behind all of that, and as such, i can't remember if the hotter single coil should produce more vapor than the cooler dual coils, but i do know that it would also depend on the type of juice you are using (the mix ratio) and upon how wet they are etc. but since DC units are usually arranged vertically along the central axis of the carto, you can bet that both coils are not going to be constantly as wet (esp after a few puffs) as a single coil unit that is run either vertically, but at the bottom of the central axis, or horizontally at the bottom of the carto. this is because the juice is naturally going to tend towards the bottom of the unit, and thus, the top coil on a DC unit is going to get dryer quicker.
now for some calculations: a 1.7 ohm coil that gets run at 3.5 volts draws 2.06 amps and generates 7.21 watts (which is turned into heat to vaporize the juice)
now take a 2.8 ohm coil and run it at 4.5 volts, this coil will draw 1.607 amps and generates 7.23 watts
these two coils, assuming they are built exactly the same, will produce EXACTLY the same vapor in every way, shape, and form. if they are identical in every way except for the resistance of the coil inside of them, they will be identical... there would be no difference in the heat of the vapor or the amount of it, because the wattage is the same, and thus the heat produced by each coil has to be the same.
if you had a 2.2 ohm coil and put it at 4 volts, you would be at 1.81 amps and 7.27 watts; again, the same exact result as the two above.
this proves that the common misconception that you can't get the same vaping experience from an LR as you can from an SR is just that, a misconception. the only thing that could make an LR give a better experience (from a VV PV) is a better inherent design of the atty/carto. otherwise, you are really better off going for an atty/carto that will be the highest resistance that you can use while still giving you the maximum possible current IF you set your PV at it's highest voltage. this will allow for the MOST flexibility (in that, you can lower the voltage down from max and realistically utilize MUCH more of the voltage range) whereas if you were to use an atty that maxes out the current (2.5 amps for many PV's) at only 4 volts, for example, then you are getting nowhere by setting the PV higher than that, because the unit will kick in it's current limiting function and force the voltage down to the point where the current stays at or below 2.5 amps. this will give you less options, as you can only go between 3 and 4 volts, instead of being able to go between 3 and 6 volts.
hope this helps everyone
p.s. i am an electronic engineering technologist and, as such, have a fair bit of experience and background in this topic...
