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Don't be fooled by the DNA 20.

Discussion in 'VV/VW APV Discussion' started by Pazazu, Jun 16, 2013.

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  1. professeur

    professeur Full Member Verified Member

    Jun 20, 2013
    Athens, Greece
    Search "el3v8tor" @ Google. The first link is a video and the three first links has some photos also.

    The list at vaporwall was fullfilled and this week they send the first mods to the owners. Its a Greek mod (in a few weeks there will be a site but not at the moment). It is telescopic with fast length change and has a new idea at the button. The button is a "joystick". At the center it "fires" and left right change the watts. I must check it with my hands to be sure that this i practical. It is made from SS. When you say "titanium" you mean the mark bugs evolved or there is another one with dna and titanium?

    The price was 185 euros (about 245 $) + 20 euros freight charge.
     
  2. rayboy55

    rayboy55 Senior Member Verified Member ECF Veteran

    Feb 11, 2012
    Quebec Canada
    Wow Thanks professeur...still they are expensive and yes the one in titanium is Mark Bugs evolved !!!Hopefully we will see a tube mod in the price range of a provari or less ...i hope loll !!!!
     
  3. wobblybootie

    wobblybootie Full Member

    Jun 19, 2013
    Dorset UK
    Argggg!! Okay folks, I have read the complete thread and I have suffered the cranial equivalent of Microsoft's Blue Screen Of Death!!! I am not an electrical engineer I got the general gist but getting into sub Ohm coils ... I don't want to have to use heat sinks or supercooling. It's all I can do to remember Ohm's Law from school 40+ years ago.!!

    I do know I want to build a 'box' mod, (just for the hell of it) and not just a mechanical one (I have done that with a couple of e-pipes) I want to build a board into the mod and was leaning toward the DNA but I guess I could look at the Vamo, Evic or SVD for less of the hard earned cash and ease of acquisition!!

    I don't have expensive Greek or German kit, just a Vamo,a Sig19b with Protank's Evod's and Nova's with a Taifun (Cotton tank) on order.

    I just want to be able to adjust the output to suit my tank/juice/mood. I am not that interested in Kudos either.

    I was struggling to make a decision before ...but now .... :confused:
     
  4. tomzgreat

    tomzgreat Ultra Member Verified Member ECF Veteran

    Jun 5, 2009
    Chino California
  5. dr g

    dr g Moved On ECF Veteran

    Mar 12, 2012
    Paradise
    If there's one thing you need to understand about subohm is that subohm doesn't necessarily mean a higher temperature. In fact it can't mean a higher temperature, or you would burn the hell out of your juice. Subohm coils take more power to achieve a similar temperature as thinner-wired coils. If you fired a subohm coil at, say, 10 watts, you'd get little if any vapor production.
     
  6. Kytrix

    Kytrix Senior Member ECF Veteran

    Dec 11, 2012
    Charlotte, NC
    My biggest plus with the DNA20 was the fact that I could fire my sub-ohm coils, something I could only acheive otherwise on a mech, but keep a constant voltage all day long instead of charging half-dead batteries 3 times a day for optimal vaping and ridiculous dragon clouds.
     
  7. rayboy55

    rayboy55 Senior Member Verified Member ECF Veteran

    Feb 11, 2012
    Quebec Canada
    This is totally awesome, great discussion and as long as we are off analogs ...we can vape the hell out of anything that we can afford and this is the great thing i like compare to analogs...we can upgrade as we go along and learn something in the process, this is great stuff guys !!!!!:rickroll::rickroll::rickroll:
     
  8. professeur

    professeur Full Member Verified Member

    Jun 20, 2013
    Athens, Greece
    This is not the right thread but i must ask...

    I always have in mind that lower resistance means higher temperature. This is not correct? These days i try higher coils (2.4-2.6) than my usual (1.5-1.8Ohmc) at the dripper and as i am not a very advanced user cannot see much difference. Just play a little with the watts.

    So lets say a coil at 1.2 ohms at 12 watts (3.8 volts) does not produce higher temperature than a coil at 2.4 ohms at 12 watts (5.36 volts) ? :confused:
     
  9. Mad Scientist

    Mad Scientist Ultra Member Verified Member ECF Veteran

    May 11, 2013
    Smokestack, PA, USA
    Lower resistance generally results in "faster" heat and higher energy (more) heat at a given voltage -- not higher temperature. In theory (yeah, not in reality) if the wick will stay wet by enough wicking, it's not possible to burn the juice -- just more and more of it will boil off as you add more energy, the temperature won't exceed the boiling point of the juice. As soon as there is any dry spot anywhere on the coil, It will get hotter and hotter until it burns the juice. So more watts (lower resistance) into a coil is really a test of wicking and wick "reservoir" performance as much as anything else.
     
  10. dr g

    dr g Moved On ECF Veteran

    Mar 12, 2012
    Paradise
    The answer is -- it depends! Resistance is simply a descriptive property of a given coil, but a given resistance can be achieved in different ways, which will behave differently. In general, resistance wire takes more current to reach a given temperature the larger it gets: Resistance Wire.Com | Nickel Chrome, Nickel Copper, and Iron Chrome Aluminum Alloys from Stock

    So, if you achieve a lower resistance by shortening the coil, you will raise current but keep the wire size the same, therefore you will get higher temperature. If you achieve lower resistance by increasing the wire size, you will raise current and raise the amount of current it takes the wire to heat.

    Looking at the chart, let's say you have a 32ga coil at 3 ohms, set at 3.7v. That gets you 1.2a, 4.6w, theoretically capable of 1600 degrees in open air (our juices are coolants so in the atomizer this is a far lower number, unless you run out of juice, which is where the burnt tastes comes from). Shortening that coil to 2 ohms, 3.7v is 1.85a, 6.84w, over 2000 degrees in open air.

    However if you raise the wire size to get the reduction in resistance ... let's say you go to a 28ga coil at 2 ohm. The 1.85a is only good for ~1300 deg. in open air. So you have actually have to go to 1 ohm to achieve the same 2000 degrees capability with 28ga.

    Now, the other half of the equation is that larger wire size means larger surface area, which means more area of contact with the wick. In order to do subohm builds, you generally need to raise the wire size significantly. So you are vaporizing more liquid at once with a larger wire coil, hence the larger clouds.

    This is also why a dual coil tends to take more power and produce more vapor than a single coil of the same resistance.

    I actually have this exact setup going on right now with two separate EVOD clone heads. One is a stock head at 2.4 ohms (32-34 ga) and one is a rebuilt head at 1.2 ohms, 30 ga. If I run both at the same wattage, the 2.4 ohm coil gets hotter in all cases. I get full vapor performance from the 2.4 head at about 11w, whereas at that wattage the 1.2 ohm head makes a weak vape. I can crank the 1.2 ohm head to 18-20w at which time it makes much bigger, thicker clouds than the 2.4 head at 11w. If I run the 2.4 head at 18w+, it burns the juice.
     
  11. tearose50

    tearose50 Vaping Master Verified Member ECF Veteran

    Feb 2, 2011
    Left coast
    Not interested in those big clouds. I'd like to be able to actually see the computer screen when I'm vaping. Plus, I don't want to have to clean my glasses every hour. [​IMG]

    On to another subject:

    Can someone tell me where these hz numbers come from?

    I keep seeing posts about the 33 on several of the Chinese VV/VW devices, 80 or 800 on the Provari and 800 or some other khz number on the DNA20?
     
  12. dr g

    dr g Moved On ECF Veteran

    Mar 12, 2012
    Paradise


    about 16:45, 33 hz is the pwm frequency of the common chinese vw chip
     
  13. tearose50

    tearose50 Vaping Master Verified Member ECF Veteran

    Feb 2, 2011
    Left coast
    Thanks -- that's one mystery solved.

    Maybe I'll go look up his Prothingy and OpusD reviews for the others.

    Edit: Still looking. The OpusD/DNA20 shows a beautiful straight consisten line -- and f ?
     
  14. rayboy55

    rayboy55 Senior Member Verified Member ECF Veteran

    Feb 11, 2012
    Quebec Canada
    I was told that the dna20 runs at 245khz !!!
     
  15. Mad Scientist

    Mad Scientist Ultra Member Verified Member ECF Veteran

    May 11, 2013
    Smokestack, PA, USA
    I think the chart and analysis ignore the thermal mass of the wet wick and heat transfer to it. The thermal mass of thicker wire is higher, that's true, but is it materially higher than any reasonable wire with the wet wick heat sink? I think the difference in performance you observe results from the surface area of the wire achieving better heat transfer to the wick. Thinner wire will indeed get hotter, but not because it has less thermal mass and less heat transfer in free air; it's because it does not contact as much wick surface area and thus has less efficient heat transfer to the juice in the wick. Are we both saying basically the same thing lol?
     
  16. dr g

    dr g Moved On ECF Veteran

    Mar 12, 2012
    Paradise
    I'm not exactly sure what you are disputing. The chart isn't disputable, that's how resistance wire works per se. Heat transfer is part of the equation, the measurements are in air, but air undoubtedly doesn't transfer heat as well as coolant liquids. The same thing would happen in a vacuum, it's basic physics. Thinner wire gets hotter with less current.
     
  17. tomzgreat

    tomzgreat Ultra Member Verified Member ECF Veteran

    Jun 5, 2009
    Chino California
    When you get into the world of RBA throw all the charts [I've Seen] out the Window

    My favorite setup is a Bottom Feeding DNA20D set at 16-20 watts on a .60 Ohm Build
    In the morning or depending on the juice I'll lower the wattage but often by mid day I'll raise it.

    Reomizer 2 RBA Atomizer
    FC-2000 Porous Ceramic Wick or a Braided Ceramic Wick [XC-116 I think]
    Kanthal 27 Gauge Wire 4-3 Wrap
    100% VG Juice using Organic Flavorings [DIY]

    What many don't realize is that it's all about the temperature of the Coils.
    My RBA Setup the FC-2000 and the XC-116 absorb a lot of the Heat. Add to that the longer surface of the wick, the airhole in the side providing aeration, the thickness of the wire and greater surface space and your coils are being kept cooler by larger space and aeration. You need more Wattage to get the coils hot enough to provide a satisfying vape.
     
  18. dr g

    dr g Moved On ECF Veteran

    Mar 12, 2012
    Paradise
    Actually the chart I posted at least is directly applicable to RBA. It's what we're all doing with RBA.
     
  19. Mad Scientist

    Mad Scientist Ultra Member Verified Member ECF Veteran

    May 11, 2013
    Smokestack, PA, USA
    I'm not really disputing so much as asking. After looking at it, I admit some confusion.

    First off, my issue was with using a free air model as applied to a wet wick. We both agree that heat transfer is higher for a wet wick so no dispute there. The concept is the same, I just knee jerked because free air has such lower heat transfer than wet wick. If a wire could transfer all of its heat uniformly to a wet wick, neither would get hotter than the boiling point of the juice. So ... On that point it would appear not to be about which wire gets hotter in free air or vacuum, but which wire can more efficiently and uniformly transfer it's heat to a wet wick.

    Thinner wire does get hotter than thicker at a given current. I'm having trouble framing the question but its along the lines of how does the foregoing interrelate with the difference in surface area between thick wire and thin, with surface area translating to heat transfer. So, a thinner wire gets hotter and transfers its heat less efficiently. Conversely, a thicker wire is less hot but transfers its heat energy more efficiently. I propose (as a strawman) that it's not so much the temperature of the wire so much as the heat transfer to the wick that allows thicker wire wrapped wicks able to handle higher current without burning. In other words, a thinner wire gets hotter and also can't transfer that heat into enough mass of the wet wick, so it gets hot spots and burns. If it could transfer its higher heat, thinner wire would "work better," but we know it doesn't. What do you think?
     
  20. tomzgreat

    tomzgreat Ultra Member Verified Member ECF Veteran

    Jun 5, 2009
    Chino California
    Hi Dr G
    I haven't been paying close attention to the thread, could you put the link to the chart that you are referring to up again. I agree that I may have been too definitive in my statement so
    I've edited my post to read, " all the charts [I've seen] "
     
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