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volts/amps/ohms explained in detail on single and dual coil atty/cartos

Discussion in 'VV/VW APV Discussion' started by Krprice84, Mar 15, 2012.

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  1. MrWarspite

    MrWarspite Super Member Verified Member ECF Veteran

    Supporting member
    Mar 20, 2012
    North Carolina
    Agreed, seems like the buzz pro and the Darwin are the only two popular vv mods that work to the limit. They are darn expensive to so that factors in.

    Im okay with the varitube cutting me off. I'll take safety first.
  2. tearose50

    tearose50 Vaping Master Verified Member ECF Veteran

    Feb 2, 2011
    Left coast
    If it tastes great at 3 volts -- why go higher?

    Is there a prize for who vapes the highest volts/amps/watts with the absolutely lowest resistance atty's?
  3. Johnny2puffs

    Johnny2puffs Moved On

    Oct 9, 2011
    I agree tea. Can't see why people want more than 2.5 amps. I vape at 3 volts and if I go to 3.5v then the juice burns. Just change to an atty that works and dump those DC's. The diffs berween SC and DC is that you only need more volts on the DC for the same taste and then your bat don't last as long.
  4. MickeyRat

    MickeyRat Vaping Master Verified Member ECF Veteran

    Mar 4, 2011
    Hickory, NC
    It really is all about taste where the 2.5 amp limitation is a problem is with low resistance stuff. For instance a 1.5 ohm dual coil, won't do real well for most people on a Lavatube.
  5. Krprice84

    Krprice84 Senior Member Verified Member ECF Veteran

    i can't believe how much misinformation is in MY OWN THREAD!! for god's sake guys, please stop posting in this thread if you aren't totally sure

    johnny2puffs, your math is completely wrong... you said that if you have a 2.5ohm dc then you have 5 ohms total...that's backwards, if you have a 2.5ohm dc then you have TWO 5 ohm coils and you have them in parallel, meaning the total resistance that the output (mod/battery/whatever) sees is 2.5 ohms. DC carto's are NOT wired in series, i repeat, they are NOT wired in series

    now, as far as the post on the second page where the guy is talking about surface areas and whatnot... i can tell you that the difference between an LR and an SR atty in surface area is going to be basically negligable. or, rather, it really won't make much, if any, difference. not likely to anyways, but what they do, just for the record, to change the resistance of a coil is make it longer or shorter, longer being higher resistance. now, my hunch for the reason you are getting different tastes is that the atty's are going to have slightly different internal designs, different materials, different bridge designs, or other things. the stove analogy not only doesn't work, but it isn't right.

    the setting on the stove isn't changing the amount of energy that is being output, it is changing the temperature of the stove (which, yes, by neccesity, changes the wattage being used, but that isn't the setting on the dial, so you can't easily "set" the burners to be at the same wattage). regardless, even if you could, it doesn't really apply here, because the larger burner is LOTS larger than the smaller one, like, more than double the surface area. with this idea, yes, the larger burner with the same wattage would likely be slightly lower in overall tempurature, because the total power disappated is over a larger surface area, by a great deal. with an atty, the SR atty is not going to be different enough in area, nor is the actual area/volume of the atty/carto different at all, so the overall heat created is still confined to the same volume and won't be different at the same wattage.

    this is a MUCH more complicated problem than we are making it, by any stretch, but the whole idea of wattage being the determining factor IS correct. the other MAJOR thing affecting taste is going to be the design of the device, as such, yes, it is worth looking into other devices, even if they are different resistance, but once you find one that works great, you shoudl be able to stick with it and alter the voltage going to it depending on the juice you are using and the temp/wattage that it tastes best at. you really shouldn't need to change to different style/resistance atty's/cartos for different juices or different vapes.

    by the way, a small difference in wattage will make a noticable difference in temp and taste. i have a feeling that this is why you are noticing a difference between an LR atty at x volts and an SR atty at y volts, even though the wattage is close; because it is not the SAME wattage, the temp is diferent and thus it tastes different. i'm pretty sure that, if the atty's are the same design (from the same manufacturer, with the only difference being the resistance) and you had someone connect them to a precision power supply and gave you the same wattage on both units, exactly, and you were blindfolded, you couldn't tell the difference between the two. in fact, i would be willing to wager money on it (so long as, like i say, the ONLY difference was the resistance of the coil - if that means it has to be longer or shorter, then fine, but that's the only difference between them... in that case they wouldn't be differable). on another note, you *could* get coils that are the same length but different resistance, even likely the same diameter too, just made up of slightly different compositions, but really, manufacturers aren't going to bother with that, it's much more reasonable to just buy a bunch of coils that are all the same ohms/unit length and cut them to different lengths for different apps

    any other questions feel free to PM or post here, but please, don't post 'info' here that you aren't sure on, because i wanted this thread to contain useful thruth, not theory or unproved thoughts, or simply wrong info

    thanks and you're welcome
  6. mav929

    mav929 Full Member Verified Member

    Mar 28, 2012
    Anchorage, Alaska
    what to you would be an optimum voltage for a duel coil or tripple at 2.0 ohms? per coil?
  7. MickeyRat

    MickeyRat Vaping Master Verified Member ECF Veteran

    Mar 4, 2011
    Hickory, NC
    I don't want to get into a fight about this but, you are technically inaccurate. You are correct, when you say that adding length to the coil is a small change in area in sq in. However, what percentage increase is it? I don't make a habit of pulling apart atomizers but, from what I've seen, you're looking at maybe 5 or 6 windings. The difference between 5 and 6 is a 20% increase in surface area. You can't credibly call that insignificant. The analogy to stove burners is good one.

    Remember that with taste and smell we detect things in the parts per million range. It doesn't take much to make a change you can taste.
  8. Johnny2puffs

    Johnny2puffs Moved On

    Oct 9, 2011
    READ MY POST PROPERLY. I am not stoopid. Been in electronics for over 30 years so I know what I'm talking about. A 2.5 ohm DC has 2 * 5 ohm coils in PARALLEL. Simple as that. I never said anything different.
    Now please apologize.
    Total ohms for a 2.5 ohm DC IN PARALLEL is:
    5*5/ 5+5 = 2.5ohms
    Do you have a problem with that now????
    You are the only one giving wrong info here. So please go away.
    "Quote' i can't believe how much misinformation is in MY OWN THREAD!! for god's sake guys, please stop posting in this thread if you aren't totally sure".End Quote. SHOOO away now.
  9. Johnny2puffs

    Johnny2puffs Moved On

    Oct 9, 2011
    No apology? OP went away?
  10. John D in CT

    John D in CT Ultra Member Verified Member ECF Veteran

    Feb 27, 2012
    This thread had a lot of potential; maybe it can be saved. I thought it was so good that I printed it out; just read the whole thing while I was taking a crap. (Good one, thanks for asking).

    I'll have to think about it a little more, but I thought the stove analogy sounded solid. And I want to fully understand whether or not a watt is a watt is a watt, no matter how it's arrived at. I'm thinking no, it isn't. I think it does have a great deal to do with the total surface area of the coil(s) and temperature of the coil(s). Again, the stove analogy.

    Anyway, I think I'm over my fascination with dual coils, and will be a single coil carto guy from now on. The juice has to be more concentrated at the bottom of a non-tank-surrounded carto, and even in one inside a tank since the slot or holes are going to be on the bottom for the most part. Interesting idea about allocating slot/hole area to both the upper and lower parts of the carto, but it's still problematic when the tank empties. I think it's better just to keep a single coil at the bottom all happy. Plus, the upper coil in a DC is bound to start scorching the polyfill, no matter how well you try to keep it moistened as you vape. Talking mainly about a non-tank carto there, but it still applies somewhat to a carto in a tank. Is the polyfill going to be uniformly saturated top to bottom? Probably not.

    OP, please come back.

    The Beatles - We Can Work It Out [Official Video] [HD] - YouTube
  11. MickeyRat

    MickeyRat Vaping Master Verified Member ECF Veteran

    Mar 4, 2011
    Hickory, NC
    Well a watt is a watt. It is the same amount of energy no matter how you get at it. Inside an atomizer, that energy is dissipated as heat on the surface of the coil. Same energy, more surface area means lower temperature. Same energy lower surface area means higher temperature. How much difference it makes can vary between juices but, it does make a difference.
  12. DaveP

    DaveP PV Master & Musician ECF Veteran

    Supporting member
    May 22, 2010
    Central GA
    Upon a quick read, KrPrice was right in his technical info, but maybe biased in his opinions of single and dual coil cartos. Contact area is important. Yes, you get half the current through each parallel coil in a DC carto simply because each coil is a higher (3.2 ohm) resistance. In parallel, they present a 1.6 ohm load to the battery, drawing the same current as a single 1.6 ohm coil would. The total wattage is the same.

    Think of it this way. Two 50 watt bulbs side by side produce the same heat and light as a 100 watt bulb. Two hoses on a Y connector output the same amount of water that flows (current) through the single hose that feeds the Y connector, but you get lower pressure (wattage) from each.

    The important point about the entire conversation is that there are many atomizer and carto designs. Try them all and make a decision using your taste and satisfaction as a guide. If you like dual coils, then use dual coils. If not, search around and find the one that makes you go "AAAH, this is it"!
  13. John D in CT

    John D in CT Ultra Member Verified Member ECF Veteran

    Feb 27, 2012
    Mickey, I can't tell if you're taking issue with what I said, or agreeing with it.

    Yes, a watt is defined as "one joule per second", and also "the rate at which work is done when an object's velocity is held constant at one meter per second against constant opposing force of one newton", but that's not what I meant by asking "is a watt a watt (oh what?)" when it comes to the business end of a cartomizer, and how that relates to the qualities of the vape.

    I maintain that there's a strong possibility that one carto operating at 10 watts can give a much different vape from another operating at the same power, even with the juices being identical.

    That's what I'm trying to get to the bottom of. I agree with you that it does seem to make a difference, but I want to understand it as completely as possible.
  14. MickeyRat

    MickeyRat Vaping Master Verified Member ECF Veteran

    Mar 4, 2011
    Hickory, NC
    I was agreeiing with you :)
  15. John D in CT

    John D in CT Ultra Member Verified Member ECF Veteran

    Feb 27, 2012
    OMFG and hot damn! Well I for one know how to take "yes" for an answer! Very cool. :)

    OK, now try this one on for size: I just posted this a while ago in another thread:

    "Open question, and one that I'm going to post in that thread [this thread], but will ask here before I forget it:

    A) It seems to me that as long as you can keep them surrounded by wet polyfill, or with proper wicking in a carto-less tank, would you not get more total vapor from two separate coils in a single carto than you would from a single coil, assuming each coil gets warm enough to reach the temperature at which a coil best vaporizes juice.

    B) If A) is true, and it's also true that each coil in a DC gets about 1/2 as warm as the coil in a SC at the same resistance and at the same voltage, would it not make sense to power the DC at twice the total watts of the SC, making each coil in the DC as warm as the single coil in the SC.


    A) DC 2.0 ohm carto at 4V = 8 watts, each coil drawing 4 watts

    B) SC 2.0 ohm carto at 4V = 8 watts, single coil drawing 8 watts. (Coil twice as warm as (A)?)

    So, would this (C) give a better vape than (A)?:

    C) DC 2.0 ohm carto at 5.6V = 15.68 watts/call it 16, each coil drawing 8 watts. Coils at same (higher) temperature as in (B) = better vape than (A)?

    (Yes, this is about 2.85 amps. The ProVari can handle 3.5, so let's leave switch capacity out of it).

    Brain ... hurts ... must ... stop ..... now ... "

    So there it is. It seems to me that it's unsatisfactory, vapor-wise/flavor-wise, if a DC is operating at the same total watts of an SC if the coils themselves aren't at the optimal temperature for producing vapor and flavor.


    Background: In that thread, the OP asked, among other things:

    "What are the differences between single coil and dual coil and why would one be better on a VV device and one on the fixed voltage device?"

    I answered:

    "Start here; volts/amps/ohms explained in detail on single and dual coil atty/cartos

    Excellent thread; answers a lot of questions, then raises a few more.

    The basics of what I took away from that thread:

    1) A dual coil (DC) atty/carto of a given resistance will contain two coils wired in parallel, each of which are twice the resistance (ohms) of the rated ohms of the atty/carto, and each of which will get half as hot as the coil in a single coil (SC) atty/carto of the same resistance (ohms).

    Example: a 2.0 ohm DC will be wired with 2 x 4 ohm coils, which in parallel will draw 2.0 ohms, but each of which will heat up about half as much as would a single 2.0 ohm coil. More resistance, less heat. Although that suddenly seems backwards. But I don't think it is.

    2) Single coil makes more sense to me than a dual coil for the simple reason that even in a tank, the lower coil will be a little more saturated than the upper coil. Without a tank, the upper coil is almost certain to run too dry much of the time.


    And that's when I fell and hit my head on the toilet and got the idea for the flux capacitor. (Well OK, not the flux capacitor, but running DC's at twice the wattage of SC's).

    Thoughts anyone?
  16. MickeyRat

    MickeyRat Vaping Master Verified Member ECF Veteran

    Mar 4, 2011
    Hickory, NC
    Electrically you are correct. If you assume that resistance of the coils is equal, a 2 ohm dual coil would be composed of 2 4 ohm coils. It takes 4V to deliver 8W to a 2 ohm resistance and each coil will see 4W.

    However, you're asking about the effect of the distribution of juice within the carto. I can't know that. Given the fact that there's variance in the juice, I don't think the manufacturer can either. I can throw some thoughts out there though. There is a point of saturation where all of the energy that the coil sees is spent vaporizing the juice. Having more juice present doesn't effect the vape once you get to that point. I think the assumption is that both coils are at that saturation point all the time.
  17. John D in CT

    John D in CT Ultra Member Verified Member ECF Veteran

    Feb 27, 2012
    It's not so much the distribution of the juice inside the carto that I'm focusing on, but rather the temperature of the coils when drawing x amount of watts.

    Consider a hypothetical case in which the coils are "perfectly" saturated, and remove juice variations from the equation.

    What I'm trying to get at is whether or not a dual coil carto would need twice as many total watts delivered to it as a single coil of the same (total) resistance in order to get each coil to the temperature at which coils best atomize juice.

    Let's say that temperature is 400F., and that feeding 10 watts to a single coil brings it to that temperature. Would not feeding 10 watts to a dual coil end up deliver 5 watts to each coil, meaning that neither one would reach that optimum temperature? That is why I'm wondering if the goal would then really be to deliver a total of 20 watts to the dual coils, with each coil getting the 10 watts that produces that hypothetically ideal temperature of 400F. (accomplished by say, 5.8 volts with a 1.5 carto, drawing about 3.4 amps).
  18. MickeyRat

    MickeyRat Vaping Master Verified Member ECF Veteran

    Mar 4, 2011
    Hickory, NC
    You're right. In effect, with a dual coil, you are powering two single coils simultaneously. So, if it takes 10W to get to the minimum vaporizing temperature on a single 4 ohm coil, it will take 20W to get to the same temperature on a 2 ohm dual coil. That said, the minimum probably won't generate enough vapor for a satisfactory vape in either case. With two coils generating the vapor, it would seem to me you wouldn't have to have the coils get as hot to get a good vape.
  19. Krprice84

    Krprice84 Senior Member Verified Member ECF Veteran

    i'm not gone, i just don't live on the forum... i have a 3.5 year old girl who i just recently received full custody of, and her mother just died of a ...... overdose (don't ask... have no clue how she came to deciding to try THAT out... but w/e)... kind of busy lately

    anyways, to j2p, the way your post was worded was mos def not clear, and from what i recall about it, was worded as though you were suggesting that the coils would be wired in series, if not, then my apologies, but you don't have to be a penis about it, simply clarifying your post would completely suffice as opposed to 'shooing' me from the thread i started

    and mickymouse... while you are correct about the surface area of the coil, the volume of the carto's is going to be the same, and the actual volume of the coil itself is likely not going to change very much, as the coils will be wound a little tighter if there is more of them, because they have to fit into the same space, and as such, the difference will not be nearly as significant as your 20% figure. yes, the actual surface area of the coil itself will be 20% greater, but the surface area is NOT the sole factor in this, the volume of the coil, volume of the carto, the volume of air going through and across the coil, and type of juice, are all factors which matter, and i am quite certain that the surface area argument is not correct... but i may be wrong

    to be honest, what we should be doing it finding someone who uses an oddyseous or other rebuildable atty, and ask them if they can make two versions of their atty and run them at different voltages to acheive the same power consumption from the two coils, with the only difference being that one coil has an extra winding, and this will answer wether it matters or not once and for all, because all other cartos are not going to create a 'controlled' experiment where only one variable is changed at a time

    anyone know someone with a rebuildable atty that would be willing to attempt this?
  20. John D in CT

    John D in CT Ultra Member Verified Member ECF Veteran

    Feb 27, 2012
    But reconsider what I proposed substituting "minimum" for my original "optimal". I don't see two coils operating below that optimal temperature as providing as good a vape as if they were each at that optimal temperature. Seems to me also that even one coil at that optimal temperature would produce a better vape; at the very least, better flavor, with the little flavor molecules being excited properly, and maybe even total vapor production as well.

    And please bear in mind, we're assuming that many variables are constant; eg. ideal coil saturation, same juice.


    Maybe think of it this way; a candle needs X amount of wind to be put out. Blowing on it with .5X of wind twice won't put it out.
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