Why does the resistance go up at random?

Discussion in 'General Rebuildable Discussion (RTA/RBA/RDA)' started by Soundsystem00, May 17, 2019.

  1. Soundsystem00

    Soundsystem00 New Member

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    I have noticed a lot of times my resistance shoots up and dulls the flavor a lot.

    Today it happened when I cleaned and rewicked my coil. It appears to be a perfect build. I use pre rolled cottons and pre built coils.

    I heat up the coil and run it under water to clean it. I thought that was okay, but is there a certain way to do it? It seems like my coil often hits funky when I do that. It was making a weird sizzle sound so I tired to unwick it and burn off any remaining water from the coil and the sizzling stopped, but then I noticed the resistance shot up from .50 to .65

    the coils are .4 but I never have gotten a .4 reading, usually the reading is around .5

    Think that I am cutting the coils improperly? I moved the coil lower and that got me a few points back but still not at .5

    What is going on?
     
  2. Vape Fan

    Vape Fan More like I am now, than I was before VU Donator Gold Contributor Member For 1 Year

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    Dry fire after cleaning?
    You could remove a wrap. That will lower resistance.
    What coil you using?
     
  3. MrMeowgi

    MrMeowgi The Vapin' Drummer Staff Member Senior Moderator VU Donator Diamond Contributor Member For 3 Years

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    Also definitely remove the cotton first. Have to remove it to dry burn burn so you can get all the water off. My coils usually are off in ohms just a bit. Never as much as a +/- .1,,, Does the rezis2go back down after you get it dry fired and wicked back up
     
  4. VinnySem

    VinnySem Silver Contributor Member For 3 Years

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    What kind of wire are you using? Stainless steel's resistance will increase as it rises in temperature. You shouldn't set the resistance of the coil except for at room temp.
     
  5. gopher_byrd

    gopher_byrd Cranky Old Fart VU Donator Gold Contributor Member For 4 Years ECF Refugee

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    Check for loose screws. The screws that hold the wire and the screws for the posts in your RDA/RTA. I had a RDA exhibit the same problems you described and I found the screw attaching the negative post had loosened just enough to start acting wonky.
     
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  6. BoomStick

    BoomStick Gold Contributor Member For 4 Years

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    Unstable resistance is an unstable electrical connection. Could be in the atomizer, the mod or between the two. Gotta sort it out.
     
  7. Spent

    Spent Member For 4 Years

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    Same problem on several RTAs. I admit I don't change coils very often. Dry fire a little brushing and usually goo to go. Occasionally I am finding to clean the posts and screws. Scraping with an Exacto blade works well. New coil, tight screws. All is good.
     
  8. The Cromwell

    The Cromwell The Frugal Vapist VU Donator Diamond Contributor Member For 3 Years

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    Sounds like you have a screw loose.
     
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  9. MrMeowgi

    MrMeowgi The Vapin' Drummer Staff Member Senior Moderator VU Donator Diamond Contributor Member For 3 Years

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    In life? Lol
     
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  10. The Cromwell

    The Cromwell The Frugal Vapist VU Donator Diamond Contributor Member For 3 Years

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    In life? That is me.:)
    Nope just a screw loose. Coil screws or 510 screw...

    every time I clean and rewick I check the coil screws. Unless I forget ;)
     
  11. zaroba

    zaroba Gold Contributor Member For 4 Years

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    Most common causes of a jumping resistance are a loose screw or dirty connection.
    The constant heating and cooling of the metal while taking hits can cause the screws holding the coils to loosen so it's good to make sure they are still tight when changing cotton. The connection between the mod and atty could also be loose or dirty causing random jumps in resistance, check for and clean any dirt on the pins.

    You said the coils are supposed to be 0.4 ohm, but if you have a *consistent* reading of 0.5 ohm this could be caused by the leg length between the posts and coils. Half a millimeter can make a difference. Maybe even resistance caused by the RDA itself.

    *NOTICE* The below is just speculation so don't take the following as truth, others can clarify.
    I imagine it's possible that for ease of design the coils were made and tested on a bench instead of in an RDA thus allowing shorter leg length, even if tested in an RDA, all are different and allow different leg lengths so it's possible yours doesn't allow the coils to be as close to the posts. I also can't imagine every single coil is tested, for the sake of easy mass production one coil could have been made (or calculated) and tested, then many more were quickly made using the same number of wraps and same diameter which can result in variation in outcome.
     
  12. Soundsystem00

    Soundsystem00 New Member

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    Thank all you guys for the responses! I don't get properly notified of responses which is why I have had to come back and check on it, sorry about that!

    Yes I removed the cotton and dry fired. The resistance reading, although improper, is usually consistent. I washed my RDA ( recurve ) and rebuilt it and it seemed to be doing a little bit better.

    I think there was a short, and/or the wire was too far down and needed to be moved up some!

    I am still struggling with good and consistent flavor but that is for another thread.

    Do you guys get a badass consistent flavor every time? Or is it luck of the draw like me, hoping that the cotton, build, and all stars will align this session? haha

    Ps yes I have a major screw loose.
     
  13. gsmit1

    gsmit1 Gold Contributor Member For 1 Year

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    I don't know if this has been mentioned, but my Warrior RDA was jumping all over the place until I figured out that the screw holding the positive pin in was loose.
     
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  14. CactusFanaticus

    CactusFanaticus Silver Contributor Member For 2 Years

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    I used a wasp for a long time, noticed once that a new build (same build as always so I knew what the coil should be) was reading too high. Checked the 510 and post screws and everything was tight and clean.
    Got to thinking maybe an invisible layer of oxidation had built up on certain parts, so I completely dissembled the wasp and cleaned all parts, posts and screws with steel wool/2000 grit sand paper and put back together. Worked like a brand new one.
     
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  15. Lasher467

    Lasher467 New Member

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    I haven't heard anyone ask What kind of wire you are using.if it's stainless it will fluxuate a little bit.of you can lock in your resistence (if your mod supports this)it will help.
     
  16. MrMeowgi

    MrMeowgi The Vapin' Drummer Staff Member Senior Moderator VU Donator Diamond Contributor Member For 3 Years

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    Just had the same with a Goon rda. The tiny screw on the bottom holding the negative pin was loose
     
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  17. Lasher467

    Lasher467 New Member

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    That is definitely a possibility.
     
  18. WotofoOfficial

    WotofoOfficial VU Vendor VU Vendor Bronze Contributor Member For 1 Year VU Challenge Sponsor

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    Related to the material of the wire.
    High Temperature will make your coil's ohm changed.

    Different material, the different range for the changes.
    Some got a little change, even the chip can't recognize it

    Heat it several times, it should keep the same ohm

    Or .... your atty ...broken ....
     
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  19. Brewdawg1181

    Brewdawg1181 New Member

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    No expert here, but have you tried the atty on another mod or ohmmeter to see if it reads consistently on all of them? Thinking one of the variables is it could be a mod issue.
     

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