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21700 build Help

Discussion in 'Batteries and Chargers' started by Lewbuh, Oct 7, 2019.

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  1. Lewbuh

    Lewbuh Full Member

    Sep 30, 2019
    hey all :)

    Recently got a Kennedy vindicator 21700 with a Kennedy 25. Using a Samsung 30t, build I’m currently using is a simple round wire kanthal build coming in at 0.19 ohms.

    Main question I had today was how low can you actually build on these batteries? reason I ask is because I really want to use some aliens or claptons. I see a lot of you tubers build quite low on this setup, pulling much more amps than the cdr and I was wandering is this actually safe to do?
     
  2. B2L

    B2L Vaping Master Verified Member ECF Veteran

    Supporting member
    Jan 14, 2012
    Jacksonville, FL
    Mooch rates the 30T at 35 amps, figuring 4V you could build at.12 ohms and be at 33.3 amps so technically be in the “safe zone”.

    Using 4V allows a little safety margin as there would likely never be an actual 4V applied considering voltage drop. I prefer a little more margin of safety however. Your .19 build comes in at 21 amps, well within the safety zone.

    Welcome to the forum!
     
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  3. Lewbuh

    Lewbuh Full Member

    Sep 30, 2019
    Thanks! I have been calculating the amps drawn with 4.2v, I guess I must have been doing it wrong. Thanks for clearing it up for me :)
     
  4. sonicbomb

    sonicbomb Vaping Master Verified Member ECF Veteran

    Feb 17, 2015
    1187 Hundertwasser
    There is no good reason to exceed a battery's CDR. If there is not enough oomph, add another battery to your setup.
     
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  5. Punk In Drublic

    Punk In Drublic Vaping Master ECF Veteran

    Aug 28, 2018
    Toronto, ON
    You know what also caught on from a YouTube video? Eating Tide Pods.

    What is much more amps and how low are their builds? Operating at or below the recommended CDR is reducing risk. The further you go beyond the CDR limit, the more risk you assume. I would take what you see on YT not just with a grain of salt, but the whole damn shaker!

    We are dealing with unknowns - voltage drop, voltage sag, variables with how people vape as an example. In order account for those unknowns we needed to operate at a proven safe(r) level, hence recommending to not exceed the CDR with maximum battery voltage.

    Alien or Claptons do not have to come in super low resistances. One of my preferred Fused Claptons I wind reads out to approx. 0.45 to 0.5 per coil. Ni80 – 4x 30awg cores with a 40awg wrap. Makes for a large surface area coil that has relatively low(ish) mass.
     
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  6. Zaryk

    Zaryk Ultra Member Verified Member ECF Veteran

    Jan 25, 2018
    Ohio
    I've been making the same coil, 4x30/40 NI80, and it indeed does work quite well. Tons of flavor, fast ramp up, and easy on the battery.
     
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  7. B2L

    B2L Vaping Master Verified Member ECF Veteran

    Supporting member
    Jan 14, 2012
    Jacksonville, FL
    That would allow even more of a safety factor which is a good thing :thumb:
     
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  8. Lewbuh

    Lewbuh Full Member

    Sep 30, 2019
    When I was watching reviews on the vindicator before I got it a lot of the reviewers were building low. Jai haze was using 0.11 on a 30t.

    I’m just not too sure if I should be calculating the amp drain at 4.0v or 4.2v to be honest.
     
  9. B2L

    B2L Vaping Master Verified Member ECF Veteran

    Supporting member
    Jan 14, 2012
    Jacksonville, FL
    If you’re trying to take it to the absolute lowest safe limit, stick with 4.2.
     
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  10. Punk In Drublic

    Punk In Drublic Vaping Master ECF Veteran

    Aug 28, 2018
    Toronto, ON
    Did Jai display the resistance on a meter? What was the voltage of his battery?

    When mitigating risk, all factors need to be accounted for. Maximum voltage from these batteries is 4.2 volts, therefore 4.2 volts needs to be factored in. That is not saying you are getting 4.2 volts at the coil, but you have no idea what the voltage is unless you measure, and measure again. So instead of dealing with an unknown, you are accounting for that unknown by using the max voltage. This is mitigating risk

    By building to 4.2 volts you are also accounting for other discrepancies, such as the accuracy of the equipment used to measure resistance, which could easily account for a +/- 0.05 ohms, perhaps even more.
     
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  11. Lewbuh

    Lewbuh Full Member

    Sep 30, 2019
    5A495DC7-4301-40A9-A92A-6E6355CC50BA.jpeg These are coming in at 0.15 so i think I’ll run these. Do love a good staged build :)
     
  12. Punk In Drublic

    Punk In Drublic Vaping Master ECF Veteran

    Aug 28, 2018
    Toronto, ON
    Try them. But also understand that there is much more to a coil than resistance. Coil mass plays a huge roll – the higher the mass, the longer the coil takes to heat up under the same power. It also takes longer to cool down.

    Some simple numbers to give an example. 0.5 ohms on mech sans voltage drop equals ~8.5 amp draw or 35 watts. A 0.5 ohm coil made from 24 awg Kanthal is twice the mass as a 0.5 ohm coil made of 26 awg Kanthal (not exactly but pretty damn close). Therefore, under the same 35 watts, 8.5 current draw (cause both resistances are the same), the 24 awg would take twice as long to heat to the same temperature. This example is using simple straight gauge wire for simplicity - but exotic coils, Claptons, Aliens, Staggered Dragon Monkey Tails, etc, can be extremely high in mass regardless of their resistance. There is a point of diminishing returns.
     
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  13. Don29palms

    Don29palms Moved On ECF Veteran

    Sep 12, 2014
    joshua tree, ca
    Those should work well.
     
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  14. Don29palms

    Don29palms Moved On ECF Veteran

    Sep 12, 2014
    joshua tree, ca
    It's hard to take some reviewers seriously when they talk about mech safety and battery safety. When you see reviewers do stuff like put in a fresh build and then fire it on a mech and then say that the build comes out to .08ohms after checking it.
     
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  15. mimöschen

    mimöschen Ultra Member ECF Veteran

    Jul 15, 2016
    You never ever get the full 4.2V from a cell. Not even from a 30T.
    When you hit the button, the voltage under load immediately sags to about 3.8V on a 35A ampdraw.

    3.8V/35A=0.11ohm

    That means a 0.11ohm coil is still inside a fresh 30T's CDR.
    On top of that the voltage drops even more because of the mod's own inherent voltage drop.
    You may count that as your safety margin.

    But:
    As the cell ages due to the heavy strain that occurs at that high ampdraw, the CDR decreases, so that safety margin goes south quite fast.

    Safety issues due to aging aside, it's still not necessary to build your coils that low, because if you do, you may rock'n roll in the beginning, but the cell gets depleted extremely fast, and on top of that you stress your cell quite heavily. That means you have to change it a lot sooner to keep on vaping and overall cycle life will be terrible, so prepare to buy replacements sooner as well.

    If you build slightly higher, you will get a lower ampdraw, but also a higher voltage/less battery sag, so the actual poweroutput will be roughly the same.
    And the lower ampdraw not only translates into a higher safety margin, but into extended vaping time and much better cycle life as well.
     
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  16. Dr. Seuss

    Dr. Seuss Super Member

    Jul 15, 2019
    I’ve been focusing on getting higher ohm builds to work well on mechs and real high gauge clapton builds with dual cores work great. The reason for this has a lot to do with my lack of trust with mechs due to inexperience and reading stories of where things went wrong. I’m glad I initially didn’t trust them otherwise I might have never considered as much the actual style of coil build vs just really thinking I had to go as low as possible with the ohms.

    On this box mech with a fresh Samsung 30T, a Dovpo Safe Link measures my volts at 4.1x. It doesn’t read any further than x.x and I don’t know how accurate it is but I tend to play on the safer side so I do my measurements using 4.2 just to have that additional cushion.

    Moral of the story is you don’t actually have to push the red line of making your coil a coil that shorts out your battery to get a good vape.

    As a side note, I know a lot of people dislike Jai Haze but I really like him. I have some legit respect for the way he does things, even though it gets a little complicated. That said, he’ll tell you himself he’s not really a “mech guy” so I wouldn’t base my choices regarding mechs solely on his decisions and I don’t think he would want you to either.
     
  17. Dr. Seuss

    Dr. Seuss Super Member

    Jul 15, 2019
    What are the gauges on all those wires?
     
  18. Ben85

    Ben85 Ultra Member ECF Veteran

    Mar 16, 2014
    Kent, UK
    To keep things simple, if you are building that low you are needing a huge cloud to get the nic you need. Just up your nic and have a smaller cloud with a higher ohm build. That’s exactly what I did and you get all these benefits;
    • Your batteries last longer.
    • Your coils last longer.
    • Your wick lasts longer.
    • You have to rebuild less.
    • Your juice lasts longer.
    • Your equipment lasts longer.
    • It is safer.
    • It is cheaper.
    • You don’t annoy the missus as much!
    It’s a no brainier for me.
     
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